2013 Subject Index: Design

• Evaluation of Impacts of Share the Road Sign on Driver Behavior Near Bicyclists
  Abstract: The interaction of motorists and bicyclists, particularly during passing maneuvers, is an area of concern to the bicycle safety community as there is a general perception that motor vehicle drivers often do not share the road effectively with bicyclists. One potential countermeasure to address this concern is the use of a bicycle warning sign with a “Share the Road” plaque. This paper presents the results of a controlled field evaluation of this treatment, which involved an examination of driver behavior while passing bicyclists. A series of field studies were conducted concurrently on two segments of a high-speed, rural two-lane highway. These segments were similar in terms of roadway geometry, traffic volumes, and other relevant factors, except that one segment included centerline rumble strips while the other did not. A before-and-after study design was utilized to examine changes in motor vehicle lateral placement as they relate to the presence of the sign treatment. The signs were found to reduce the proportion of motor vehicles that passed bicyclists in the central lane position, providing evidence that the sign is effective in shifting motor vehicles away from the right edge of the travel lane. However, the sign treatment did not significantly affect the physical buffer distance between the bicyclists and passing motorists or the proportion of motor vehicles that crowded bicyclists as they passed. Vehicle type, bicyclist position, and the presence of centerline rumble strips or opposing traffic were also found to affect lateral placement during passing maneuvers.
  Authors: Kay, Jonathan; Savolainen, Peter Tarmo; Gates, Timothy J.
  Authors: Kay, Jonathan; Savolainen, Peter Tarmo; Gates, Timothy J.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-0164
• Delay Analysis of Simulated Single-Lane Roundabout with Dedicated Bus/Truck Slip Lane
  Abstract: Simulated delay performance of single-lane roundabouts with an adjacent slip lane (bypass) for right turns is evaluated under varying bus and truck traffic percentages and two slip lane exit types (free-flow and yield). A microsimulation assessment considers experimental balanced flow scenarios with different right-turning bus and truck traffic percentages (low, moderate, and high) and with a proposed dedicated lane, compared to no slip lane. Simulated slip lane right-turning traffic volumes range from 50 to 500 vehicles per hour. Results indicate that average delay of a roundabout with slip lane and under varying bus or truck traffic has confirmed a non-linear relationship with slip lane volumes and is sensitive to changing bus or truck traffic percentages, before oversaturation occurs. As expected, results indicate that a free-flow slip lane exit type significantly reduces total roundabout average delay, compared to having no slip lane with bus or truck traffic. Yield slip lane exit types also reduce roundabout total average delay with bus or truck traffic but to a lesser degree. With a free-flow slip lane exit type designated as a dedicated bus lane, overall average roundabout delay was reduced 12% (the estimated 95% confidence interval of reduction estimated between -19% and -5%). With a dedicated truck slip lane, overall average roundabout delay was reduced 9% (the estimated 95% confidence interval of reduction estimated between -16% and -2%). A dedicated bus slip lane shows a more significant improvement of delay than a dedicated truck slip lane, for a single-lane roundabout.Key words: Roundabout, slip lane, average delay, dedicated bus or truck lane, VISSIM.
  Authors: Al-Ghandour, Majed N.
  Authors: Al-Ghandour, Majed N.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-0151
• Three-dimensional Finite Element Analysis of Hot-Mix Asphalt Overlay Mix Design to Control Reflective Cracking
  Abstract: This study examines the effectiveness of HMA overlay design strategies for the purpose of controlling the development of reflective cracking. A parametric study was conducted using a 3D Finite Element (FE) model of a rigid pavement section including Linear Viscoelastic (LVE) material properties for the Hot Mix Asphalt (HMA) overlay and non-uniform tire-pavement contact stresses. Several asphalt mixtures were tested in the surface, intermediate, and leveling course of the HMA overlay. Results obtained show that no benefits can be anticipated by using either Polymer-Modified (PM) or Dense-Graded (DG) mixtures instead of Standard Binder (SB) mixtures in the surface or intermediate course. For the leveling course, the use of a PM asphalt binder was found beneficial in terms of mitigating reflective cracking. As compared to the SB mix, the use of PM asphalt mixture in the leveling course reduced the level of longitudinal tensile stress at the bottom of the HMA overlay above the PCC joint by approximately 30%.
  Authors: Ghauch, Ziad
  Authors: Ghauch, Ziad
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 555
  Paper Number: 13-0223
• Correlation Between Crash Severity and Embankment Geometry
  Abstract: The severity of a roadside feature is often based on survey responses and tends to emphasize extreme crash events, thereby overestimating the average severity of a particular feature. In order to maintain accuracy, severity must be dependent on the characteristics of the feature, such as the embankment geometry of a foreslope. In this study, crash severity was related to embankment geometry by examining real-world accident data over a seven-year period in the State of Ohio. This was done by correlating the number of severe and fatal accidents to the exposure of particular slope geometries. Slope geometry was described by slope steepness and fill height, and its exposure was described by traffic volume and total unshielded mileage. Severity was adjusted for posted speed limits as well. The Roadside Safety Analysis Program (RSAP) was calibrated such that the distribution of severe injury and fatal accidents accurately reflected real-world data. Using this calibrated version of RSAP, the new severity indexes were studied and equations were created to correlate severity index to functional class, fill height, slope steepness, and posted speed limit. After controlling for variation in traffic volume and speed limit, the local highway classification provided the highest severity index, in part due to relaxed safety treatment practices on the lower-volume roads. The severity index for a local highway class was increased relative to the default values used in RSAP to accommodate this finding. Freeways, rural arterials, and urban arterials experienced reduced severity indexes relative to default values used in RSAP.
  Authors: Schrum, Kevin; Sicking, Dean L.; Albuquerque, Francisco Daniel B.; Reid, John D.
  Authors: Schrum, Kevin; Sicking, Dean L.; Albuquerque, Francisco Daniel B.; Reid, John D.
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 631
  Paper Number: 13-0238
• Assessment of Shear Capacity of Existing Reinforced-Concrete Solid Slab Bridges
  Abstract: Several existing reinforced concrete solid slab bridges in the Netherlands do not meet the criteria for shear when calculated according to the recently implemented Eurocodes. The shear capacity is assessed by comparing the design beam shear resistance to the design value of the applied shear force due to the dead load, permanent load and live load. Transverse load redistribution which occurs in slabs is not taken into account.To evaluate a large number of slab bridges, a first round of assessments is necessary to determine which bridges need a more detailed shear analysis. Also, a method to take into account transverse load redistribution in slabs is sought.To study the behavior of slabs in shear, a series of 26 slabs and 12 slab strips are tested until failure. The results of these experiments are compared to the beam shear capacity and the state-of-the-art in beam shear research to compare the shear behavior of beams and slabs. Recommendations for the shear assessment of slabs are formulated, and used to verify the shear capacity of 10 cases. This “Quick Scan” approach is compared to the AASHTO provisions, indicating that the “Quick Scan” approach is more conservative than the AASHTO provisions. However, the underlying target reliability index is significantly different for both approaches.For the existing bridges in the Netherlands, the proposed method can analyze a large number of cross-sections and thus help prioritize the efforts of the owners such that cases which need a more detailed shear analysis are identified.
  Authors: Lantsoght, Eva Olivia Leontien; van der Veen, Cor; Walraven, Joost; de Boer, Ane
  Authors: Lantsoght, Eva Olivia Leontien; van der Veen, Cor; Walraven, Joost; de Boer, Ane
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 628
  Paper Number: 13-0319
• Modeling the Relationship Between the Radius and Superelevation in Horizontal Curve Design
  Abstract: The paper presents a methodology for correlating the radius of horizontal curve (R) and the superelevation rate (e) when the radius is above the minimum. The method proposed, implements the radial utilization friction factor (fR) concept. The relationship between e and R was established by assuming linear or parabolic relationship between the superelevation rate and the radial friction coefficient and generating e-fR distribution factors (ãL, ãP) correspondingly. The proposed models are sensitive to the superelevation policy by applying the desired maximum superelevation rate that is appropriate with the design speed. The results were compared to the e-R relationships recommended by the United States policy on geometric design of highways (AASHTO): method 5 (for high speed facilities) and method 1. Both models generated intermediate radii results between AASHTO method 5 and method 1. The highest difference between AASHTO method 5 and the proposed models and between AASHTO method 1 and the linear model occurs when the radius reaches its maximum value for a minimum superelevation (emin=2%). The linear model resulted in lower radii design values than the parabolic model and is therefore superior in terms of topography harmonization and right of way.
  Authors: Bassan, Shy
  Authors: Bassan, Shy
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 727
  Paper Number: 13-0367
• Emission Estimation at Multilane Roundabouts: Effect of Movement and Approach Lane
  Abstract: This research explores the effect of multilane roundabouts located on urban corridors on traffic performance and pollutant emissions generated from vehicles. It further compares the emission of vehicles moving through the roundabout as they use either the entry left or right lane. The paper uses the speed trajectories from a field data collection at four multi-lane roundabouts in Aveiro, Portugal. To estimate the second-by-second emission generated from the vehicle during different acceleration-deceleration cycles, the "Vehicle Specific Power" (VSP) emission methodology is applied. This paper also develops predictive models using congestion-specific vehicle speed profiles for two-lane roundabout approaches. The paper further implements the predictive models and second-by-second speed trajectories to compare the emission generated from a vehicle entering the roundabout using right lane with a vehicle entering the roundabout using left lane. The hypothesis is that right lane and left lane may have different flow rate and may face different conflicting circulating flow; therefore, their emission rates might be different.This paper tests the hypotheses that difference in; a) lane flow (left v.s. right lane); b) conflicting flow for left and right lane; and c) overall congestion level effects the emission amounts generated from vehicles in each lane. Under low congestion levels vehicles in right lane emit more pollutant because they have on average higher speeds and sharper acceleration and deceleration rates. For high congestion levels if flow rates for left and right are equal, vehicles in left lane produce more emission because vehicles in left lane experience longer stop-and-go cycles and have different speed trajectory than vehicles in right lane.
  Authors: Salamati, Katy; Coelho, Margarida Cabrita; Fernandes, Paulo Jorge; Rouphail, Nagui M.; Frey, H. Christopher; Bandeira, Jorge
  Authors: Salamati, Katy; Coelho, Margarida Cabrita; Fernandes, Paulo Jorge; Rouphail, Nagui M.; Frey, H. Christopher; Bandeira, Jorge
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 626
  Paper Number: 13-0420
• Modeling Impacts of Access Design and Spatial Pattern on Crash Risks of Pedestrians and Bicyclists on Urban Multilane Highways in Florida
  Abstract: This paper presents a study on the impacts of access design and spatial pattern on the risk of pedestrian and/or cycling crashes at access points on urban multilane highways. Two prediction models, using negative regression and logistic regression, were developed to evaluate the impacts in terms of crash frequency and injury severity respectively. For developing the models, crash records were collected at 153 access points with different access designs for a period of 4 years (2007-2010) on the state roads in Florida.Results of this study show that, four-leg access point with directional median opening is most likely to increase the frequency of pedestrian/bicycle crashes at access points than other access designs at all spatial locations. Inner lanes experience the most pedestrian/bicycle crashes, followed by side roads (SR) and outside lanes (TO) for all access types. Three-leg access point with closed median opening and three-leg access point with full median opening experience a higher injury risk if a pedestrian/bicyclist crash occurs at an access point. Medians and inner lanes experience the highest injury risk if a pedestrian/bicyclist crash occurs at an access point. Middle lanes, outside lanes, left turn bays, crossing walks are more likely to increase injury severity of pedestrian/bicycle crashes than road side, side roads, and auxiliary lanes. In terms of crash occurrence, the top “dangerous” points are inner lanes, side roads, and outside through lanes with the access design of four-leg access point with directional median opening. In terms of injury severity, the top “dangerous” points are medians with any access design and inner lanes with the access designs of three-leg access point with closed or full median opening. Based on the results, suggested countermeasures for improving pedestrian/bicyclist safety at access points were provided.
  Authors: Wang, Zhenyu; Lin, Pei-Sung; Chen, Hongyun; Lu, Jian John; Deng, Weiping
  Authors: Wang, Zhenyu; Lin, Pei-Sung; Chen, Hongyun; Lu, Jian John; Deng, Weiping
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-0386
• Cracking Analysis of Precast Concrete Segmental Box Girder Bridge
  Abstract: The Hathaway Bridge, an eastbound and westbound bridge pair, is located in Panama City, Florida, USA. Each of the pair consists of a single box precast concrete segmental girder with a deck width of 24.4 m (80 ft). The lengths of the eastbound and westbound bridges are 1031.43 m (3384 ft) and 1162.93 m (3815 ft) respectively. To date, these are the largest single-cell precast segments without internal struts fabricated in the USA. During construction many web cracks developed in the external anchorage areas. The purpose of this investigation is to identify the main causes of the cracks and to provide some design recommendations for large precast concrete segmental box girders. First, a brief description of the bridge is given. Then, analytical models for the bridge, post-tensioning forces, and construction forces are presented. The analytical results show that the external longitudinal post-tensioning forces can cause significant high tensile stresses in the interior face of the web around the anchorages. The information presented in this paper can assist bridge engineers in the design of concrete segmental box girder bridges.
  Authors: Huang, Dongzhou
  Authors: Huang, Dongzhou
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 498
  Paper Number: 13-0452
• Modeling Operating Speed using Traffic, Posted Speed Limit, and Geometric Characteristics
  Abstract: Designers recognize operating speed as a measure of roadway consistency and driver expectancy. By assessing operating speed, designers have an opportunity to assess the expected speed of individual vehicles traversing successive roadway elements. While most previous studies focused on how horizontal curvature affects free-flow speed, several other factors can influence vehicle operating speed. This paper, using speed data collected on tangent section of rural freeways and rural highways in Texas (two-lane and four-lane), determines the relationship between operating speed, posted speed limit, and other selected independent variables. To account for the effect of geometrics and traffic characteristics, researchers developed speed prediction equations. The significant variables for four-lane, limited access freeways are posted speed limit, number of ramps within 3 miles, percent trucks, lane (inside or outside), median width, left shoulder width, and vehicle type (car or truck). The significant variables for four-lane, non-limited access highway are posted speed limit, downstream horizontal curve angle, lane (inside or outside), median width, left shoulder width, right shoulder width, vehicle type (car or truck), and light level (day or night). The significant variables for two-lane, non-limited access highway are posted speed limit, number of access points within 1,000 ft, number of horizontal curves within 1 mile downstream of site, number of horizontal curves within 1 mile upstream of site, lane width, vehicle type (car or truck), and light level (day or night). These findings provide insight into how select variables affect operating speeds.
  Authors: Fitzpatrick, Kay; Robertson, James; Park, Eun Sug; Iragavarapu, Vichika; McDaniel, Darren
  Authors: Fitzpatrick, Kay; Robertson, James; Park, Eun Sug; Iragavarapu, Vichika; McDaniel, Darren
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 727
  Paper Number: 13-0391
• Resilient and Permanent Deformation Characteristics of Unbound Pavement Layers Modified by Geogrids
  Abstract: The benefits of geogrids in reducing permanent deformation of flexible pavements are generally recognized and have been shown in numerous laboratory and field studies. On the other hand, although the resilient moduli of unbound pavement materials are important property inputs in the mechanistic-empirical (ME) pavement design process, the impact of geogrids on unbound layers’ resilient behavior remains unclear according to previous studies. The focus of this paper is on resilient behavior of unbound layers and permanent deformation of soft soil subgrade modified by geogrids placed at the base-subgrade interface. Two sets of reduced-scale accelerated pavement tests were conducted on scaled pavement structures built over two types of soft soil subgrade. Each set of accelerated tests consists of four sections, among which three sections were modified with different geogrids and one section left unmodified as a control. Instruments were embedded in the subgrade to measure resilient and permanent deformations of the subgrade. Nondestructive tests using a lightweight deflectometer (LWD) were conducted on pavement layers along with the progression of construction. Surface deflections and subgrade resilient deformation under the impulsive LWD loads were recorded. The test sections were then subjected to repetitive moving wheel loading by means of a one-third-scale model mobile load simulator (MMLS3). Subgrade resilient and permanent deformations were measured at intervals of the wheel load applications. The surface deflection measurements and instrumentation measurements of subgrade resilient deformation under the LWD load indicate that the geogrids did not have an appreciable impact on the resilient behavior of the base layer and subgrade. Subgrade resilient deformations measured along with the repetitive wheel loads also suggest that the effects of the geogrids on the resilient responses of the subgrade were not evident. However, through the two sets of accelerated tests, two of the geogrids consistently exhibited benefits in reducing the permanent deformation in the subgrade.
  Authors: Tang, Xiaochao; Stoffels, Shelley M.; Palomino, Angelica M.
  Authors: Tang, Xiaochao; Stoffels, Shelley M.; Palomino, Angelica M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 480
  Paper Number: 13-0479
• Bicycle-Specific Traffic Signals: Results from State-of-the-Practice Review
  Abstract: This paper presents the results of a survey of North American jurisdictions with known installations of bicycle-specific traffic signals and a review of available related engineering guidance. Surveys were sent out to agencies in twenty-three jurisdictions (twenty-one in the United States and two in Canada) that requested detailed engineering aspects of the signal such as placement, mounting height, lens diameter, backplate color, type of actuation, interval times, use of louvers, and performance. A total of 63 intersections and 149 separate signal heads are included in this paper. The results of the survey highlighted variety in several design elements utilized by agencies when implementing bicycle signals. This variety might impact cyclist and motorist comprehension as well as the ability to utilize the bicycle signal head in a variety of intersection configurations. A subsequent review of the guidance documents available to engineers and planners revealed generally consistent guidance with regard to the design of bicycle-specific traffic signals. The generation of guidance on bicycle signals as grown substantially in recent years and, given the accelerated deployments of bicycle-specific signals themselves, it is likely that there will be less variety in future designs.
  Authors: Thompson, Sara; Monsere, Christopher M.; Figliozzi, Miguel
  Authors: Thompson, Sara; Monsere, Christopher M.; Figliozzi, Miguel
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-0536
• Integrating Rolling-Wheel Deflectometer Measurements into Pavement Management Systems Using Multivariate Statistical Methods and Fuzzy Logic
  Abstract: The Louisiana Department of Transportation and Development (LADOTD), conducted a research project on approximately 1400 miles of asphaltic concrete roadways with the Rolling Wheel Deflectometer (RWD). The major outcomes of the study were to assess the effectiveness of the RWD as a structural assessment tool on Louisiana Highways and to introduce the RWD index (RI).The purpose of this paper was to define RI ranges for the treatment selections or pavement structural conditions linked to current LADOTD PMS methods using multivariate (Factor Analysis), descriptive (Analysis of Variance (ANOVA)) statistical methods, and fuzzy logic-functions.The Factor Analysis revealed that RI could be generally used as a single index to assess the pavement structural conditions.The ANOVA analysis revealed that RI could not be used to establish the four treatment methods typically used by LADOTD. However, the ANOVA analysis did reveal that the RI could be used to infer whether a pavement was structurally-sound or deficient. If discovered to be structurally- deficient, additional structural evaluation would be required such as with an FWD.Fuzzy logic/set theory was utilized to establish fuzzy functions for the structurally-sound and structurally-deficient pavement conditions along with RI threshold ranges per thickness group. Equations were derived to produce RI threshold values for pavement thicknesses less than 12 in. The equations may be used for pavements thicker than 12 in., but with caution. For large segments of roadways, algorithms were provided to assess whether pavements were structurally- sound or structurally-deficient based on RI.
  Authors: Gaspard, Kevin; Zhang, Zhongjie; Elseifi, Mostafa A.
  Authors: Gaspard, Kevin; Zhang, Zhongjie; Elseifi, Mostafa A.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 809
  Paper Number: 13-0544
• Extension of the AASHTO Model for Horizontal Sightline Offset to Apply to Beginnings and Ends of Simple Horizontal Curves.
  Abstract: Sight distance is an important element of design of curved sections of highways. To ensure that design sight distance is provided on curved sections, the AASHTO guideline requires that insides of horizontal curves be cleared of obstructions to sight. However, the guideline’s analytical method for determining the extent of clearance is suitable only for middle sections of horizontal curves that are longer than sight distance. The guideline suggests use of graphical or computational methods for determining offsets for cases its model is inapplicable. The graphical method is tedious and difficult to integrate into design computer models. The computational method suggested is useful only for circular curves that are longer than sight distance but the mathematical background used to develop it is lacking hence its analytical aspects are unknown. This study developed a new analytical model for clearance offsets for sections that are not covered by the AASHTO model. Model development started with deriving equations for a roadside spiral curve which acts as a boundary for the area that accommodates sightlines on insides of curves. Main factors in the equations are driver location, sight distance, and curve radius. Equations for offsets were then derived as ordinates from horizontal alignment to the spiral curve. Design charts were then developed for short curves and for long curves to work with the existing AASHTO model for maximum offset. The results of this study will be of interest to engineers undertaking new designs, improvement designs for sites with limited sight distance, and maintenance.
  Authors: Mauga, Timur
  Authors: Mauga, Timur
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 727
  Paper Number: 13-0558
• Pavement Management: Capturing Surface Treatment Effectiveness
  Abstract: Acquiring detailed knowledge of surface treatments effectiveness is required to improve performance-based decisions for allocating resources to preserve and maintain pavements on any road network. Measurement of treatment effectiveness is a complex task that requires historical records of treatments with observations of before and after performance trends. Lack of data is often an obstacle that impedes development and incorporation of surface maintenance treatments into pavement management. This paper analyzes the effect of surface treatments on asphalt paved arterial roads for several control sections. The method uses a Transition Probability Matrix to capture main effects mapping mean trends of surface improvement and pavement structure decay. It was found that surface treatments have an immediate effect reducing the rate of loss of structural capacity. Pavements with IRI smaller than 1.4 m/km did not seem to benefit from surface treatments. Those with IRI higher than 1.66 m/km gained from 6 to 8 years of additional life. Reset value for surface treatments fall between 1.18 and 1.29 m/km. This paper aims to serve to practitioners seeking to capture and incorporate effectiveness of surface treatments (i.e., crack-sealing) into Pavement Management.
  Authors: Amador-Jimenez, Luis; Amin, MD Shohel Reza
  Authors: Amador-Jimenez, Luis; Amin, MD Shohel Reza
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 662
  Paper Number: 13-0568
• Critical Analysis of Value Added by Independent Cost Estimate Consultant to Construction Manger-General Contractor Project Delivery Method
  Abstract: The Construction Manager/General Contractor (CMGC) project delivery method is an emerging project delivery method in the transportation industry. As part of its Every Day Counts (EDC) program, the Federal Highway Administration (FHWA) is promoting the use of CMGC through Peer Exchanges. One recurring theme of the Peer Exchange was the fact that value was added to a construction project during the preconstruction phase by the early involvement of the contractor and the Independent Cost Estimate (ICE) consultant. A content analysis of the presentations given at the most recent Peer Exchange in Boston, Massachusetts, along with four case studies from ICE consultants were reviewed along with literature on the topic to determine the extent of the value added to the CMGC process by involving the ICE consultant.
  Authors: Schierholz, Jeanna; Gransberg, Douglas D.
  Authors: Schierholz, Jeanna; Gransberg, Douglas D.
  Year: 2013
  Document Type: Paper
  Subject: Construction; Design
  Session: 244
  Paper Number: 13-0613
• Statistical Determination of Agricultural Vehicle-Induced Bridge Distribution Factor Threshold
  Abstract: Most studies to date on live-load distribution factor (DF) determination have focused on the examination of bridges under normal highway-type vehicles. Many bridges are in use on rural roadways where agricultural vehicle travel is common and therefore the impacts of their atypical load types should be explicitly considered. Developing systematic methodologies accounting for their effects are also critical for more reasonable safety assessment of rural bridges. The primary objective of this study is to develop a statistical framework to determine DFs for rural bridges subjected to agricultural vehicles. A sample bridge in a rural area of Iowa was selected for demonstration of the proposed statistical framework. The proposed procedure consists of multiple parts including live load field testing, finite element simulations, and statistical analyses. A network of multiple strain sensors were installed at the critical locations on the bridge to monitor strain time histories resulting from passes of farm vehicles with known characteristics. Strains were utilized to compute field measured DFs and also used to calibrate analytical models. As part of the model simulation, farm vehicles commonly found in the United States were chosen and applied to the model to calculate their DFs. Statistical thresholds for the exterior and interior girders were calculated by performing a statistical analysis of the computed data. The thresholds were compared to the AASHTO code-specified DFs (for both the Standard Specification and the LRFD Specification), indicating the interior girder limit was below yet the exterior limit was above the AASHTO values.
  Authors: Seo, Junwon; Phares, Brent Matthew; Dahlberg, Justin; Wipf, Terry J.; Abu-Hawash, Ahmad
  Authors: Seo, Junwon; Phares, Brent Matthew; Dahlberg, Justin; Wipf, Terry J.; Abu-Hawash, Ahmad
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 500
  Paper Number: 13-0633
• Methodology to Identify Factors Associated with Pedestrian High-Crash Clusters Using GIS-Based Local Spatial Autocorrelation
  Abstract: In order to identify high crash locations, the Tennessee Department of Transportation (TDOT) has an extensive road safety audit program which uses criteria based on the ratio of crashes to average daily traffic but does not target locations with a high number of pedestrian crashes since there are no pedestrian counts. Apart from ratio approach, a robust methodology is not currently available to identify pedestrian high-crash locations in Tennessee. The objective of this study is to develop a different methodology based on Anselin’s Local Moran I index in Geographic Information System (GIS) to detect high crash clusters and investigate the factors that influence the concentration of pedestrian crashes. Using pedestrian crash data from Shelby County in Tennessee, the study found that spatial dependence plays a strong role during the analyses of pedestrian crashes. These spatial dependencies, accounted through spatial autocorrelation, helped to detect statistically significant clusters of crashes in a GIS framework. These clusters were then overlaid with selected socio-economic and population demographic data in order to identify their association with high crash clusters. The study found the following factors to be associated with high crash clusters: when more than 25% percentage of the population is 18 years of age and younger, when the population of seniors is greater than 13%, when there’s a high population density of low income people, and when the percentage of families below poverty level is greater than 10%. The cluster maps may help transportation agencies to understand issues of pedestrian crashes for safety enhancements.
  Authors: Emaasit, Daniel; Chimba, Deo; Cherry, Christopher R.; Wilson, Jessica; Kutela, Boniphace
  Authors: Emaasit, Daniel; Chimba, Deo; Cherry, Christopher R.; Wilson, Jessica; Kutela, Boniphace
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-0634
• Introducing Otta Seals for Low-Volume Roads in Tonga
  Abstract: The Kingdom of Tonga’s road network, comprising approximately 640km of public roads, has had minimal road maintenance over the past decade. As a result, the road network is rapidly deteriorating. The World Bank funded Transport Sector Consolidation Project is supporting the Government of Tonga in implementing a road maintenance program to prolong the serviceability of the road network. However, due to the limited capacity of the local contracting industry, and a severe lack of quality road surfacing aggregate, traditional surfacing methods for periodic maintenance and road upgrading are not suitable. Innovative surfacing technologies, such as Otta Seals, were adopted to overcome the local limitations. The main objective of this paper is to document the introduction of Otta Seals to Tonga and the experience to date. It will also briefly capture the applications, benefits and limitations of Otta Seals, and the reasons why they have been considered for Tonga. The paper provides a brief review of the local contracting industry and the availability of locally sourced aggregate in Tonga, and the effects that these have on the choice of pavement surfacing alternatives. The first trial sections were awarded to a local contractor in January 2012, and the works are planned to start after the rainy season in July 2012. The process of introducing the new technology has to date been successful and progress of this project is being monitored by a number of other South Pacific countries that are faced with the similar constraints.
  Authors: Wilkinson, Scott J; Visser, Alex T.; Henning, Theuns F. P.; Bennett, Christopher R.; Faiz, Asif
  Authors: Wilkinson, Scott J; Visser, Alex T.; Henning, Theuns F. P.; Bennett, Christopher R.; Faiz, Asif
  Year: 2013
  Document Type: Paper
  Subject: Construction; Design; Pavements
  Session: 245
  Paper Number: 13-0673
• Development of Full-Scale Reflective Cracking Test at the FAA NAPTF
  Abstract: Asphalt concrete (AC) overlays must be designed and constructed to withstand reflective cracking. Unfortunately, the current Federal Aviation Administration (FAA) overlay design procedure (Advisory Circular 150/5320-6E) does not address this common form of premature failure. This paper presents a research project that was aimed at studying one of the general accepted causes of reflection cracks - horizontal movements concentrated at joints in the existing portland cement concrete (PCC) pavement. A prototype, Temperature Effect Simulation System (TESS) was developed at the FAA National Airport Pavement Test Facility (NAPTF) such that the joint opening and closing due to temperature changes can be simulated mechanically. A test pavement representing typical airport overlay structure was constructed to support full-scale tests. Both theoretical and experimental studies were performed to determine key test parameters, critical pavement temperature, joint opening, loading rate, and AC-PCC interface bonding condition. Preliminary full-scale tests demonstrated that the TESS could not only generate forces that create precise and repeatable joint openings but also effectively control the pavement temperature. Instrumentation data revealed that once bottom-up reflection cracks initiated, crack development can quickly progress. When the crack length reached a certain level, the crack propagation rate would slow considerably. Information and data presented in this paper are of immediate assistance to the General Aviation Airports carrying small and light aircraft and experiencing significant temperature variations.
  Authors: Yin, Hao; Barbagallo, Donald
  Authors: Yin, Hao; Barbagallo, Donald
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 579
  Paper Number: 13-0695
• Cyclist Behavior on Exclusive Bike Path: Longitudinal Analysis
  Abstract: With the rapid increase of bicycle modal share in North America, the need for more refined models arises in order to capture and model cyclist behaviour on bike facilities.Hence, this paper presents a comparison of a set of six bike-following models. The results of these models was compared to real world data collected with a GPS devices for a pair of cyclists in a following situation without opportunity to overtake. The paper presents also some finding on fundamental relationships using data collected by video at a fixed location on a bike facility. Finally, the paper presents a behavioural comparison between the bike-cyclist and the car-driver systems.The analysis and the results indicate that both bike-following models and fundamental relationships present interesting potentials to reproduce real world data given additional data.
  Authors: Manar, Abdelaziz; Desmarais, Jean-Philippe
  Authors: Manar, Abdelaziz; Desmarais, Jean-Philippe
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-0699
• Superload Evaluation of Millard Avenue Bridge over CSX Railroad
  Abstract: A series of superloads crossed the Millard Avenue Bridge which spans over the CSX railroad. This bridge is located in Oregon, Ohio, on the route from the Port of Toledo to a nearby oil refinery. Upon request of the cities of Toledo and Oregon, load tests and load ratings were performed to verify that 15 superloads could safely traverse the bridge, determine if any measurable damage was caused by the heavy loads and establish rating procedures for future superloads. The bridge is a steel kinked girder with a composite deck having 5 continuous spans, with lengths varying from 114 ft. to 152 ft. The overall width of the Bridge is approximately 67 ft. This paper discusses testing and analyses done to assess the behavior of the bridge due to superloads crossing. Load tests were carried out prior to any superload crossings, during the heaviest superload crossing and during and after the last superload crossing to characterize the resulting bridge performance. Particular features discussed are the assessment of changes in bridge behavior, establishment of load rating for future superload crossing, and the behavior of forces in the staggered cross-braces nearest the girder kinks.
  Authors: Hammada, Ahmmed A.; Nims, Douglas; Hunt, Victor J.; Commander, Brett; Helmicki, Arthur
  Authors: Hammada, Ahmmed A.; Nims, Douglas; Hunt, Victor J.; Commander, Brett; Helmicki, Arthur
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 317
  Paper Number: 13-0240
• Modulus of Soil Reaction Values Observed in Ohio Thermoplastic Pipe Deep-Burial Project
  Abstract: The researchers at Ohio University have examined various aspects of the buried pipe-soil interaction problem by analyzing the data they obtained during their thermoplastic pipe deep burial project. In this paper, the modulus of soil reaction (or the stiffness) of the backfill materials that enveloped the test pipes in the project is examined. This soil modulus is one of the key properties of the composite pipe-soil system that dictates how the pipe will perform. This property is usually selected from a published table that is arranged in terms of the soil type and the relative compaction achieved. This modulus has rarely been computed using the actual field pipe performance measurements. Analysis of the deep burial project data showed that a thin poorly-compacted zone existed in the backfill soil near the pipe-backfill soil interface. The contribution of this zone to the overall horizontal deflection of the pipe was greater when a relatively loose backfill material was placed around the corrugated pipes. The field data-based modulus values were reasonable for dense granular backfill materials but were higher than what was expected in light of both AASHTO-LRFD specifications and laboratory 1-D compression test results. No straightforward one-to-one correlation was determined between the relative compaction and the soil modulus. The Soil Stiffness Gauge (SSG) readings cannot directly represent the actual modulus values in the range of strains typically seen in buried pipe problems. Finally, the elastic solutions (particularly those under the full-bond interface) appear to be useful for estimating the modulus of the backfill soil.
  Authors: Masada, Teruhisa; White, Kevin
  Authors: Masada, Teruhisa; White, Kevin
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Geotechnology
  Session: 216
  Paper Number: 13-0336
• Determining Impact of Degree of Blending Between Virgin and Reclaimed Asphalt Binder on Predicted Pavement Performance Using Mechanistic-Empirical Pavement Design Guide
  Abstract: Past studies have indicated binder from reclaimed asphalt pavement (RAP) aggregates do not fully blend within the hot mix asphalt (HMA), resulting in a partial degree of blending (DOB). The degree of blending is defined as the percentage of RAP binder that is effectively mobilized within the mix. This study will focus on determining the impact of DOB on predicted pavement performance using MEPDG level I analysis of 25% RAP mixes with three RAP sources. Dynamic complex modulus tests were conducted on each RAP source with two conditions: full blending and a calculated “Actual” DOB. Most state agencies assume full blending, which is an assumption that may lead to under asphalting or a relatively stiffer mix. However, it is unclear how this will affect the predicted pavement performance. For the full blending samples, it was assumed that all of the RAP binder was mobilized in the mix, and the virgin binder was offset accordingly. The “Actual” DOB samples were mixed after a DOB was determined. MEPDG level I analysis was conducted using typical structures, climate, and traffic conditions for the state of New Jersey. Also rutting and fatigue cracking performance between the two DOBs were compared for each of the RAP sources. The results indicate DOB has a negligible effect on fatigue and rutting performance for the three RAP sources tested, all of which had high actual DOB’s, greater than 85%. Therefore, for RAP with such high DOB values, full blending assumption would be cost effective and would not compromise the pavement performance. However, RAP variability will need to be controlled to ensure quality performance.
  Authors: Coffey, Sean; DuBois, Eric; Mehta, Yusuf A.; Purdy, Caitlin
  Authors: Coffey, Sean; DuBois, Eric; Mehta, Yusuf A.; Purdy, Caitlin
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 377
  Paper Number: 13-0571
• Analysis of Impacts of Specimen Type on Dynamic Modulus and Predicted Pavement Performance
  Abstract: This study focused on determining the impacts of specimen type on dynamic modulus and flexible pavement predicted performance. Mixtures that were evaluated included both commonly-used dense-graded asphalt and those modified with emerging technologies. Dynamic modulus (|E*|) data was measured with two different test methods (IDT and Uniaxial Compression) and then analyzed using prediction tools (Mechanistic Empirical Pavement Design Guide (MEPDG) software, Quality Related Specification Software (QRSS), and the Asphalt Mixture Performance Tester (AMPT) Quality Assurance (QA) Program). Pavement distresses that were predicted included rutting in the surface layer as well as fatigue cracking. Performance predictions based on |E*| data from laboratory reheated and compacted specimens were equivalent to those resulting from the plant-compacted and field-compacted specimens. The results suggested that it may not be necessary to require plant-compacted or field-compacted asphalt specimens. A comparison of the different analysis tools also suggested that the MEPDG can be used effectively with Level 2 inputs, in lieu of requiring Level 1 inputs, to predict the service life of flexible pavements. By performing a parametric analysis, it was established that the MEPDG-predicted distresses were reasonable and the MEPDG may prove an effective substitute for the QRSS software. The data supported that transportation agencies can choose their preferred test method and specimen type and expect similar performance based on the pavement distresses predicted. It was recommended that agencies should select their method based upon the type of pavement distress most likely to occur at the design location.
  Authors: Guercio, Maria Chiara; McCarthy, Leslie Ann; Bennert, Thomas A.; DeJarnette, Van
  Authors: Guercio, Maria Chiara; McCarthy, Leslie Ann; Bennert, Thomas A.; DeJarnette, Van
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 239
  Paper Number: 13-0724
• Evolution of Bridge Damage-Detection Algorithm
  Abstract: This paper describes several of the many steps required to develop one of the many pieces of the structural health monitoring (SHM) system puzzle. This development has undergone a series of steps, iterations, and refinements including initial concepting, alpha-testing, analytical investigation, beta-testing, concept upgrading, and field evaluations. Although not necessarily a “blue-print” for developing such systems, this serves as a case-study for taking an initial concept through multiple steps culminating in a validated approach. As SHM becomes a more widely accepted and adopted bridge evaluation protocol, it will be imperative that developers understand the steps required to develop such systems. This work represents one example of such a process.
  Authors: Phares, Brent Matthew; Lu, Ping; Wipf, Terry J.; Greimann, Lowell; Seo, Junwon
  Authors: Phares, Brent Matthew; Lu, Ping; Wipf, Terry J.; Greimann, Lowell; Seo, Junwon
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 525
  Paper Number: 13-0730
• Multi-objective Optimization Model And Evolutionary Algorithm To Plan Uav Cruise Route For Road Traffic Surveillance
  Abstract: Unmanned Aerial Vehicle (UAV) was used to collect traffic information of road segments not installed with traffic detectors, therefore, it¡¯s necessary to plan UAV cruise route for traffic surveillance so as to minimize UAV cruise cost as much as possible. First, a multi-objective optimization model of planning UAV cruise route was proposed, which aimed to minimize UAV cruise distance and minimize the number of UAVs used respectively. Then, an evolutionary algorithm based on Pareto optimality technique was proposed to solve multi-objective UAV cruise route planning problem. Next, a case using UAV to monitor 14 road segments near Tongji University in China was studied, the case results showed that optimized cruise distance and the number of UAVs used were reduced by 38.54% and 33.33% respectively compared to the initial optimal solutions, this demonstrated that the proposed evolutionary algorithm was feasible and effective. Finally, some discussions of using UAVs for traffic surveillance were given.
  Authors: Li, Li
  Authors: Li, Li
  Year: 2013
  Document Type: Paper
  Subject: Construction; Data and Information Technology; Design
  Session: 729
  Paper Number: 13-0735
• Impact of Long and Heavy Vehicles on Pavement Damage
  Abstract: In the present paper the effect of vehicle configuration and traffic characteristics on the damage induced in pavements by traffic is investigated numerically. A three dimensional time-dependent pavement-vehicle interaction analysis is performed in order to study the impact of the parameters mentioned above on the mechanical response of flexible pavements. The analysis is based on a fast and robust computational procedure, developed by the authors. The numerical algorithm utilizes the three-dimensional finite element solution of the reduced problem of one tyre pavement interface loaded with tyre pressure. Afterwards, a superposition procedure based on fast Fourier transform techniques is applied to find the pavement response to moving loads. The method is general and capable of capturing the stress-strain response to any arbitrary loading history.One particular area of study with employing the current procedure is the analysis of long and heavy vehicle impact on pavement damage. Two major modes of distress, i.e. cracking and rutting have been discussed for 6 different truck types with 2 speeds. It is shown that an accurate numerical model provides a more accurate explanation of different distress modes. Moreover the conventional analysis and design methods with layered linear elastic behaviour assumption for asphalt layer are unable to capture several important aspects of pavement response.
  Authors: Khavassefat, Parisa; Jelagin, Denis; Birgisson, Bjorn
  Authors: Khavassefat, Parisa; Jelagin, Denis; Birgisson, Bjorn
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 554
  Paper Number: 13-0756
• Synthesis of State of the Art in Visibility Detection Systems Applications and Research
  Abstract: Visibility is a critical component to the task of driving on all types of roads. The visibility detection and warning systems provide real-time, automated detection as well as appropriate responses to counteract reduced visibility conditions due to fog, heavy rain, snow, smoke, dust or haze by informing drivers of present conditions and lowering the speed limits to match the reduced visibility condition. The objective of this research is to provide a synthesis of visibility detection systems and traffic control techniques that are developed and/or implemented in the US and around the world. This paper provides an overview of the best practices of fixed visibility systems at areas of recurrent dense fog and mobile systems for seasonal visibility reduction for areas of predicted seasonal fog or smoke from wildfires. Ongoing research efforts of developing new camera-based visibility detection systems are also discussed.
  Authors: Ahmed, Mohamed M.; Abdel-Aty, Mohamed A.; Shi, Qi; Abuzwidah, Muamer
  Authors: Ahmed, Mohamed M.; Abdel-Aty, Mohamed A.; Shi, Qi; Abuzwidah, Muamer
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 550
  Paper Number: 13-0832
• Precision of High-Speed Inertial Profilers for Asphalt Pavement Smoothness Measurements
  Abstract: The Florida Department of Transportation conducted a study to assess the precision and accuracy of its High-Speed Inertial Profilers (HSIPs) used for evaluating the smoothness of asphalt pavements. Eight HSIPs and six asphalt test sections including three dense-graded and three open-graded were included in the study. Profiler agreement in terms of repeatability and reproducibility was rated using the International Roughness Index (IRI). Profiler agreement in terms of repeatability, reproducibility, and accuracy was also assessed using the profile cross-correlation method. A SurPRO 3500 was used as a reference device for the HSIPs accuracy evaluation. A laser tracking device was evaluated as a possible operational improvement technique. The maximum IRI variability at a 95% confidence level within a single HSIP was less than 3.5 in/mi, and 2.0 in/mi for open graded and dense-graded pavements, respectively. The maximum IRI variability at a 95% confidence level between any two HSIPs was less than 5.8 in/mi and 3.8 in/mi for open graded and dense-graded pavements, respectively. The HSIPs repeated and reproduced the IRI measurements well for all test sections and surfaces. The HSIPs demonstrated the highest profile repeatability, reproducibility, and accuracy on the dense-graded medium-smooth surface and the lowest results on the open-graded medium-smooth surface. HSIPs repeatability improved by 8% on the average when using a laser tracking device. The results also indicate that current and proposed repeatability and accuracy criteria could not be met on most pavements surfaces tested.
  Authors: Mraz, Alexander; Nazef, Abdenour; Lee, Hyung Suk; Holzschuher, Charles R.; Choubane, Bouzid
  Authors: Mraz, Alexander; Nazef, Abdenour; Lee, Hyung Suk; Holzschuher, Charles R.; Choubane, Bouzid
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 552
  Paper Number: 13-0859
• Setting Up Otta Seal Trials for the South Pacific Islands
  Abstract: This paper presents the supporting monitoring programme for several Otta Seal Trials in the South Pacific region. This surfacing technology has been considered for this region given the scarcity of suitable aggregates for traditional surfacing such as thin chip seals. In order for this technology to be accepted within the region, Otta Seal Trials were set up in order to a) introduce the technology to the region and b) to demonstrate the practicality and appropriateness of this technology within the geology, environment and traffic loading.A monitoring guideline was developed that specifies the establishment of the test section, assessment procedures and the data that are collected on a regular basis. The philosophy for these requirements was to developed procedures that required minimal training of assessors while at the same time would yield useful data that could be utilized for statistical analysis of the surface performance.The setting up of the Otta Seal Trials for the South Pacific Islands has confirmed a number of recommendations related to road performance experiments including:•Clear definition of the objectives for the trials is important as it has a direct influence on the scale and assessment/monitoring philosophy for the trial;•Only collect the data items needed to an accuracy and sophistication required to provide useful data for the analyses considered to answer the objectives/questions;•Trials should be designed within context of available resources for conducting the monitoring.
  Authors: Henning, Theuns F. P.; Visser, Alex T.
  Authors: Henning, Theuns F. P.; Visser, Alex T.
  Year: 2013
  Document Type: Paper
  Subject: Construction; Design; Pavements
  Session: 245
  Paper Number: 13-0911
• Hot In-Place Recycling of Open-Graded Friction Course
  Abstract: ABSTRACTOpen graded friction course (OGFC) is widely used in Florida and many southern states as a final friction surface in high speed roads. FDOT friction policy requires the use of OGFC on multilane highway facilities with design speeds greater than 50 miles per hour. OGFC reduces the possibility of hydroplaning and water splash during rain, thereby reducing crashes. About half the Florida State Highway System is surfaced with OGFC, amounting to about 22,000 lane miles of roads.The use of FC-5, the current OGFC mix type in Florida, started in 2000. Some roads with FC-5 have reached the end of their useful life and have been milled and resurfaced. Given the high cost of FC-5 mix, it made economic sense to try to reuse the prime aggregate and high quality material incorporated in OGFC using the hot in-place recycling (HIR) process. The HIR process heats, hot-mills the surface pavement layer, applies a rejuvenating agent, mixes and then places the material in one pass. The process uses 100% of the existing road material and can produce significant cost and environmental savings (1).This paper reports on three attempts to hot in-place recycle OGFC in Florida. One was to hot in-place recycle an FC-5 mix as part of a hot in-place recycling project in Pasco County, Florida (SR-54) in 2012. The second is laboratory study of recycling FC-5 mix based on samples taken at SR-60 in Polk County, Florida in 2011. The third references SR-471 case study conducted by FDOT in 2002 in which an OGFC (type FC-2) was hot in-place recycled, lasted 10 years to date and still remains in service.The three referenced projects have shown that HIR of OGFC can be done successfully and should be considered as a cost effective rehabilitation option in the future. FC-5 is 0.75 inch thick. The recycling thickness for successful HIR is 1.0 to 2.5 inches. Thus, recycling FC-5 requires blending it with the dense-graded mix beneath it. The blending ratio of the two mixes depends on the thickness of each layer. The gradation of the recycled mix was dense graded. The blending ratio can be varied by changing the recycling depth and can produce either coarse or fine mix. While the recycled mix is not open- graded and does not meet FDOT’s requirement, it provides an economical option to milling and resurfacing OGFC. That option is to recycle the old OGFC into the structural layer and resurface with a new OGFC. Current resurfacing practice entails milling the FC-5 and a portion of the structural layer underneath it, replacing the structural layer then replacing the FC-5 course. FC-5 cannot be overlaid and must be removed before overlay. The OGFC can be in-place recycled and mixed with the structural layer underneath, and then a new friction course can be placed over the recycled mix. This can save money as it eliminates the need to mill and replace the top structural layer under the FC-5. Raising the road grade by 0.75 inch, the thickness of the new FC-5 layer, while increasing the section’s structural number, remains an issue in this approach. This may be acceptable if there are no limitations on raising the road elevation in the selected project.Among the interesting findings is the increased amount of fines in the mix compared to construction gradation. Over time, the voids in the mix get filled with dirt and dust. Water flow brings fines into the mix and as the water evaporates, it leaves the fines in the voids, reducing the drainage capacity and resulting in a finer mix.
  Authors: Ali, Hesham A.; Sayed, Sayed M.
  Authors: Ali, Hesham A.; Sayed, Sayed M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 555
  Paper Number: 13-0924
• Benefits Achieved from Florida's Accelerated Pavement Testing Program
  Abstract: The need for faster and more practical evaluation methods under closely simulated in-service conditions prompted the Florida Department of Transportation (FDOT) to initiate an accelerated pavement testing (APT) program in 2000. APT allows monitoring of a pavement system’s performance and response to accumulation of damage within a much shorter time period, typically within weeks instead of years. The primary objective of FDOT’s APT program is to continuously improve the performance of Florida’s pavements. As such, implementation and technology transfer of research findings are of primary importance. The APT program has become a critical component of FDOT’s pavement research program. The success of the program can be attributed to the careful selection of research projects that address vital issues and prolong the life of Florida’s roadways. Engineers have successfully used the APT program to gain insight into new pavement technology and design methods that laboratory testing alone could not provide. Most important is the impact the APT program has had on pavement construction and design practices. APT research has led to the revision of FDOT’s Flexible Pavement Design Manual and construction specifications and has provided critical information to policy makers. While specific tangible benefits cannot be always directly determined for each project, it is clear that significant savings can be directly attributed to the implementation of APT research. For example, it is estimated that over $4 million is saved each year as a result of APT research and implementation of polymer modified asphalt binders and fine-graded asphalt mixtures.
  Authors: Greene, James; Choubane, Bouzid; Jackson, N. Mike
  Authors: Greene, James; Choubane, Bouzid; Jackson, N. Mike
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 737
  Paper Number: 13-0961
• Bayesian Approach to Updating Markov-Based Pavement Performance Prediction Models
  Abstract: The Markov decision process is one of the most common probabilistic prediction models used in infrastructure management. Where insufficient data exists, expert knowledge is commonly used to derive a Markovian transition probability matrix (TPM). Eventually, every pavement management system will progress to a level where inspection measurements from the network are organized into a database to be used for performance prediction. The best way to use this body of data to improve the initially-developed TPM is to combine prior expert knowledge with new observations. This paper proposes a method to periodically update Markovian transition probabilities as new inspection data becomes available. Bayesian inference is used to accommodate uncertainty in the expert-derived initial probabilities and measurement errors from inspection of the network. A data set of asphalt concrete pavement observations from the MnROAD test facility is used to illustrate the proposed method.
  Authors: Tabatabaee, Nader; Ziyadi, Mojtaba
  Authors: Tabatabaee, Nader; Ziyadi, Mojtaba
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-0993
• Modeling In Situ Performance of Culvert Joints in a Pavement Structure
  Abstract: The Saskatchewan Ministry of Highways and Infrastructure (MHI) is responsible for approximately 65,000 culverts. Under typical field state conditions, corrugated steel pipe (CSP) culverts have a design life of approximately 30 years. These culverts can pull apart at the joints due to the level of friction between the culvert and surrounding soil, causing the culvert and ultimately the road to fail. This study employed a computational road model to investigate the strain behaviour along the culvert-road soil interface and to examine the mechanisms by which culvert joints pull apart. Two pavement structures were modeled in two different moisture conditions: a primary and secondary road structure, in both wet and dry moisture states. The secondary road structure in a wet moisture condition state had overall higher magnitudes of shear and horizontal strains compared to the other road structures and condition states. From a dry to wet moisture condition state on the secondary road shear strain increased by 119%, the horizontal strain in the longitudinal direction increased by 114%, and the horizontal strain in the transverse direction increased by 116%. This research showed that the horizontal strain in the longitudinal direction was greater in magnitude for the wet moisture condition states in comparison to the dry moisture condition states. Improved mechanistic modeling of culverts in diverse field state conditions could significantly assist road engineers to better design culvert installations. Accurately modeling and diagnosing culverts non-destructively could also help identify early signs of structural failure, which would enable road agencies to implement a proactive methodology for culvert remediation.
  Authors: Soares, Roberto; Sharipov, Farukh; Marjerison, Brent L.; Wandzura, Colin; Berthelot, Curtis F.
  Authors: Soares, Roberto; Sharipov, Farukh; Marjerison, Brent L.; Wandzura, Colin; Berthelot, Curtis F.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 782
  Paper Number: 13-1048
• Roundabout Networks for Robust, Walkable Communities
  Abstract: Modern roundabouts have continued to proliferate in the United States since the first were constructed in the 1990s. Roundabouts offer well-documented safety, capacity, and environmental benefits as compared with most other intersection types. Yet most U.S. roundabouts are built at either isolated locations or in short corridors. The Complete Streets movement has made great inroads in getting engineers to consider the needs of all users when designing a roadway. Yet jurisdictions which have adopted Complete Streets have largely confined themselves to cross sections; the actual layout of the street network is relatively unchanged. New Urbanism has encouraged planners and developers to rethink the layout and spatial arrangement of local streets, but these concepts have typically not made it to the adjacent arterial network.This paper proposes a roundabout-based network of through streets which integrates Complete Streets and Access Management concepts with provision for mass transit and non-motorized transport. A variety of intersection and corridor treatments are explored for interfaces between the roundabout network, local streets, limited access facilities, and existing arterial grids. The roundabout network is intended as a drop-in replacement for the major thoroughfare plans common to most fast-growing cities.
  Authors: VanElswyk, Abram
  Authors: VanElswyk, Abram
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-1042
• Quality Management and Assessment of Shotcrete Liners with Sonic Methods
  Abstract: Shotcrete liners are being utilized more frequently in transportation infrastructure as retaining structures and tunnel covers. Despite their economic advantages to portland cement concrete, the initial quality of construction and long-term durability of shotcrete liners are of concern among some highway agencies. The need for a quantitative construction quality management methodology to ensure adequacy and uniformity of strength and thickness is desirable. Shotcrete liners should be tested periodically in critical structures to assess possible material deterioration and to detect the onset of defects such as delamination and voids. The impact echo and ultrasonic surface wave methods are two nondestructive sonic methods that are effective for those purposes in concrete structures. The effectiveness and challenges of applying these methods to shotcrete liners are investigated in this paper. To that end, several 6 ft by 6 ft slabs made of concrete and shotcrete with different thicknesses and in some cases with embedded defects were evaluated. Unlike concrete slabs, shotcrete slabs exhibit some spatial heterogeneity. In addition to heterogeneity, surface roughness of shotcrete adds some complications into data interpretation in terms of thickness estimate. Despite these challenges, results from this study demonstrate that delamination and voids within the shotcrete liners can be detected well by using these sonic methods.Keywords: shotcrete, concrete, delamination, nondestructive testing, impact echo, surface wave.
  Authors: Azari, Hoda; Nazarian, Soheil; Yuan, Deren
  Authors: Azari, Hoda; Nazarian, Soheil; Yuan, Deren
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: AFF60
  Paper Number: 13-1084
• Ultra-Rapid Underpass: TBM Excavation in Soft Ground from Surface Elevation Without Shaft or Large-Scale Open Cut Pit
  Abstract: The new tunneling technology in soft ground called URUP (Ultra Rapid Underpass) was developed in an attempt to allow construction of a roadway underpass tunnel in a busy intersection where there is limited work space available while being required to accelerate a construction schedule to minimize adverse impacts to the local environment. The URUP method enables a Tunnel Boring Machine (TBM) to launch and hole through directly from ground level safely maintaining the ground stability from zero to ultra thin ground coverage and eliminate the need for the large-scaled open cut excavation typically required for launching and receiving a TBM. This paper introduces a new shield tunneling technology named URUP and discusses the experimental construction undertaken in the development process. The paper also provides project reports on three of the public projects that applied the URUP method.
  Authors: Zick, Paul; Sugihara, Hiroaki; Takatoku, Yuhei; Sada, Soichi
  Authors: Zick, Paul; Sugihara, Hiroaki; Takatoku, Yuhei; Sada, Soichi
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 215
  Paper Number: 13-1080
• Structural Response of Low-Fill Box Culvert Under Static and Traffic Loading
  Abstract: Box structures have been commonly used underneath highways. They are installed at grade or at great depths. When a box culvert is buried at a shallow depth, vertical pressure and impact due to traffic load transferred onto the roof of the culvert can induce deflections of the culvert. The effect of traffic load on the response of the culvert depends not only on the magnitude, pattern, and speed of the traffic load but also on the pavement structure. To investigate these factors, a reinforced concrete box culvert under three roadway sections (concrete pavement, concrete shoulder, and unsurfaced fill) was tested under static and traffic loads. The total thickness of pavement layers was 26 inches within the pavement section and decreased gradually towards the end of the culvert through the shoulder and the unsurfaced section. The culvert was instrumented with displacement transducers and strain gauges under the roof and pressure cells on top of the roof within the unsurfaced fill. A low-boy truck with a known axle configuration and load was used to apply seven static load combinations and traffic loads at different speeds. Deflections under the roof and pressures on the roof were measured. Measured strains were too small to be meaningful for analysis. The test results show that the magnitudes of the deflections of the culvert roof under static loads were in the small to large order from the concrete pavement, the concrete shoulder, to the unsurfaced fill. The truck at a higher speed generally induced more deflections than that at a lower speed or stopped.
  Authors: Acharya, Raju; Han, Jie; Brennan, James Joseph; Parsons, Robert L.; Khatri, Deep Kumar
  Authors: Acharya, Raju; Han, Jie; Brennan, James Joseph; Parsons, Robert L.; Khatri, Deep Kumar
  Year: 2013
  Document Type: Paper
  Subject: Design; Geotechnology; Pipelines
  Session: 249
  Paper Number: 13-1113
• Risk Factors Associated with Crash Severity on Low-Volume Rural Roads in Denmark
  Abstract: The current study analyzes the risk factors associated with crash severity on low-volume rural roads, including crash characteristics, driver attributes and behavior, vehicle type, road features, environmental conditions and zone attributes. The data consist of a comprehensive set of crashes occurred on low-volume rural roads in Denmark between 2007 and 2011. The modeling approach entails a generalized ordered logit model due to its advantage in accommodating the ordered-response nature of severity while relaxing the proportional odds assumption. Crash involvement rates show that 20% of the drivers involved are intoxicated and 40% fail to use seatbelts. Moreover, about 25% of the crashes involve vulnerable road users, while 18% involve heavy vehicles. Model estimates and pseudo-elasticities show that aggravated crash severity is significantly and positively associated with (i) alcohol and failure to wear seatbelts, (ii) involvement of vulnerable road users, (iii) involvement of heavy vehicles, (iv) speed limits of 80-90 km/h, (v) longer distance to the nearest hospital, and (vi) socio-economically vulnerable rural regions.
  Authors: Prato, Carlo Giacomo; Rasmussen, Thomas Kjær; Kaplan, Sigal
  Authors: Prato, Carlo Giacomo; Rasmussen, Thomas Kjær; Kaplan, Sigal
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 571
  Paper Number: 13-1236
• Novel Approach for Diagnosing Cycling Safety Issues Using Automated Computer Vision Techniques
  Abstract: The use of traffic conflicts for safety diagnosis has been gaining acceptance as a surrogate for collision data analysis as they provide insight into the failure mechanism that leads to road collisions. This paper demonstrates an automated proactive safety diagnosis approach for cycling safety using video-based computer vision techniques. Traffic conflicts are automatically detected and conflict indicators such as Time to collision (TTC) are calculated based on the analysis of the road-user positions in space and time. Additionally, non-conformance of vehicles to travel regulations; specified as failure to respect yielding signage at the intersection are identified. The procedure is applied for the safety analysis of a newly installed bike lane at the southern approach of a major Bridge (Burrard Bridge) in Vancouver, British Columbia. The results showed a high exposure of cyclists to traffic conflicts. Vehicle conflicts at the location were also identified and analyzed. Practical solutions to address the safety issues at the location were presented. The proposed approach overcomes shortcomings with reliance on collision data and the manual observations of traffic conflicts.
  Authors: Sayed, Tarek; Zaki, Mohamed H.; Autey, Jarvis
  Authors: Sayed, Tarek; Zaki, Mohamed H.; Autey, Jarvis
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-0744
• Observations of Daytime and Nighttime Passing Maneuvers on Two-Lane Rural Road in Spain
  Abstract: Passing is one of the most complex maneuvers on two-lane rural roads, thus it has important effects on road safety and traffic operation. It is affected by driving behavior, road geometry, traffic volume, traffic composition as well as other external factors. This research was developed to compare passing process under daytime and nighttime conditions. An experimental methodology was designed to collect video data of passing maneuvers at a two-lane rural road segment located in the surroundings of Valencia (Spain). Two methods were used: firstly, external observations with six video cameras of four passing zones; secondly, an instrumented vehicle equipped with video cameras and laser rangefinders, which was drivenove slightly below the operating speed along a longer road segment of the same road in order to be passed by other vehiclesdrivers.A total of 291 maneuvers were observed; up to 20% of them during night. A macroscopic analysis shows that approximately 17% of passes are under nighttime conditions, although passing frequency and passing demand decrease during night. Besides, individual behavior of drivers which pass is different at nighttime compared with daytime. Maneuvers limited by the presence of an opposing vehicle are performed faster at night, even if accepted gaps are longer. In this case, a more difficult perception of distances to opposing vehicles and of their speeds explains the differences. On the other hand, maneuvers limited by sight distance (without a visible opposing vehicle) are slower during night. This matches a traditional hypothesis, which assumed that passing at night is safer since headlights from opposing vehicles anticipate their position before being seen.
  Authors: Llorca, Carlos; Moreno, Ana Tsui; Garcia, Alfredo; Perez-Zuriaga, Ana Maria
  Authors: Llorca, Carlos; Moreno, Ana Tsui; Garcia, Alfredo; Perez-Zuriaga, Ana Maria
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 222
  Paper Number: 13-0953
• Performance Prediction Models for Cracked, Seated, and Overlaid Concrete Pavements in California
  Abstract: Crack, seat, and overlay (CS&O) is a rehabilitation technique that has been used on Jointed Plain Concrete Pavements (JPCP) in California. Although widely used, only a few studies have attempted to develop performance prediction models for pavements rehabilitated employing this technique. The purpose of this study was to evaluate CS&O performance in terms of surface roughness and transverse reflection cracking. Performance data for CS&O sections in three different geographic regions in California were used to develop regression performance models. These models can be incorporated into the Caltrans Pavement Management System (PMS) to predict future performance, assist in life-cycle cost analysis, and optimize the allocation of resources. The results of a sensitivity-analysis suggest that sections age is the most significant factor affecting the deterioration of CS&O pavements followed by the annual traffic level, in terms of ESAL, and layer thickness ratio. Sections age variable would implicitly include the impact of environmental loading cycles. Other factors related to subgrade conditions, temperature variations, and construction variability could not be investigated since data were not available. However, their impacts are inherent in the models.
  Authors: Rahim, Ashraf M.; Fiegel, Gregg L.; Holland, T. Joseph; Lim, Seungwook
  Authors: Rahim, Ashraf M.; Fiegel, Gregg L.; Holland, T. Joseph; Lim, Seungwook
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 579
  Paper Number: 13-0996
• Urban Environments, Pedestrian Friendliness, and Crossing Decisions
  Abstract: The objective of this experimental study is to identify the differentiation made by pedestrians between various urban environments, notably in terms of perception of walking pleasantness and safety, and from the point of view of road crossing decision. This experiment further aims to identify the environmental features that pedestrians use and the inferences they develop to explain their road crossing decision. Sets of five photographs presenting five different environments (city center, inner suburbs, public housing in the outskirts, commercial zone in the outskirts and countryside) have been presented to 77 participants shared in three age groups (pre-adolescents, young and middle adults). Their decision to cross or not, their perception of pleasantness and safety and the elements they take into account to take a decision were collected for each environment presented. The results show the pedestrians’ perceptions of the pleasantness and safety of public spaces, in terms of walking, largely vary with urban environments and the crossing decision significantly varies according to the environment. Pedestrians crossed significantly more in city center than in the other sites presented. Presence and function of the buildings and quality of the sidewalks are key factors to explain their crossing decision, by enabling them to infer the density of pedestrians and traffic and vehicle speed.
  Authors: Montel, Marie-Claude; Brenac, Thierry; Granié, Marie-Axelle; Millot, Marine; Coquelet, Cécile
  Authors: Montel, Marie-Claude; Brenac, Thierry; Granié, Marie-Axelle; Millot, Marine; Coquelet, Cécile
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Safety and Human Factors
  Session: 208
  Paper Number: 13-1143
• Study on Optimization Method of Signal Control at Four-Leg Roundabout Based on Single Release
  Abstract: This paper proposes a single release based signal control method for four-leg roundabouts. Single release is a signal control method of roundabouts, which makes each approach as a single phase, and releases the vehicles of each approach clockwise. In order to improve the capacity, two kinds of optimizing control schemes are presented. Based on the schemes, the phase design was made and the Webster¡¯s optimal cycle length formulation was improved. By comparing the two optimizing signal control schemes, the applicable condition of the signal control schemes is discussed. Finally, a simulation study was conducted for a real Roundabout, and the result shows the validity of optimization control schemes.
  Authors: Zuo, Junzhong; Xu, Liangjie; Cheng, Yang
  Authors: Zuo, Junzhong; Xu, Liangjie; Cheng, Yang
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-1156
• Calibration of VISSIM Roundabout Model: A Critical Gap and Follow-up Headway Approach
  Abstract: VISSIM roundabout models have been widely applied in practice to facilitate analyzing the operational performance of roundabouts. To prepare a VISSIM roundabout model for analysis, an essential prerequisite is to calibrate the model by adjusting parameters until real-world roundabout operations are reproduced in the simulation model. Previous calibration research has used qualitative analysis to study the impact of VISSIM parameters on roundabout capacity. Comprehensive calibration guidelines, parameter values based on field data, and quantitative sensitivity analyses of parameters are necessary to facilitate accurate modeling of roundabouts. This paper addresses these important needs. Speed trajectories of free-flow entering vehicles were collected in the field using a radar sensor. Analysis identified that the approach to a roundabout entrance can be divided into four speed zones reflecting different stages of drivers’ deceleration maneuver. Location, length, speed distribution, and deceleration rate parameters for the VISSIM Reduced Speed Areas (RSA) were determined through the analysis of the radar data. Comparisons between Conflict Areas (CA) and Priority Rules (PR) were also investigated, and revealed that using PR can result in more consistent and repeatable gap acceptance behavior. In addition, the impact of VISSIM parameters on critical gap and follow-up headway was quantitatively analyzed through sensitivity analysis of minimum gap for PR, speed distribution and deceleration rate for RSA, and additive and multiplicative settings for the Wiedemann 74 model. Numerical recommendations for calibrating VISSIM roundabout models were ultimately developed, and validated via a case study.
  Authors: Li, Zhixia; DeAmico, Michael; Chitturi, Madhav V.; Bill, Andrea R.; Noyce, David A.
  Authors: Li, Zhixia; DeAmico, Michael; Chitturi, Madhav V.; Bill, Andrea R.; Noyce, David A.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-1176
• Identification of Physical Transportation Infrastructure Vulnerable to Sea Level Rise
  Abstract: The objective of this research was to integrate current data sources to develop a methodology for assessing the potential impacts of sea level rise (SLR) on Florida’s state and local transportation infrastructure to assist transportation planning. The proposed approach integrates the Florida Department of Transportation (FDOT) information system, and local roadway and hydrologic data with existing topographical and geological data to facilitate i) the evaluation of current and projected SLR impacts on Florida’s coastline and low-lying terrain areas, and ii) the identification of the physical transportation infrastructure components that are most likely to be affected by frequent to continuous flooding due to SLR. A projection of SLR, and the timing for same was outlined using a benchmark approach that brackets time intervals as opposed to specific timing for improvements. Further research to evaluated the impact of groundwater levels as an exacerbating factor with respect to sea level rise. Storm surge is a future, more difficult area of investigation.
  Authors: Bloetscher, Frederick
  Authors: Bloetscher, Frederick
  Year: 2013
  Document Type: Paper
  Subject: Construction; Design; Environment
  Session: 509
  Paper Number: 13-0926
• A CONDITIONAL AUTOREGRESSIVE MODEL FOR SPATIAL ANALYSIS OF PEDESTRIAN CRASH COUNTS ACROSS NEIGHBORHOODS
  Abstract: This work examines the relationship between 3-year pedestrian crash counts across Census tracts in Austin, Texas, while controlling for land use, network, and demographic attributes, such as land use balance, residents’ access to transit, sidewalk density, lane-mile densities by roadway classes, and population and employment densities (by type). The model specification allows for both region-specific heterogeneity and spatial autocorrelation via a Poisson-based conditional auto-regressive (CAR) framework and is estimated using Bayesian Markov chain Monte Carlo method. Least-squares regression estimates of walk-miles traveled per zone serve as the exposure measure. Model results suggest that higher shares of residences near transit stops are associated with greater pedestrian crash risks, ceteris paribus, presumably since such access encourages more walking activity and more potential conflict between pedestrian and vehicles movements. Sidewalk provision is associated with lower pedestrian crash rates, presumably due to lower speeds and narrower roadways in network-dense and sidewalk-prominent settings, though exposure is likely higher.
  Authors: Wang, Yiyi; Kockelman, Kara
  Authors: Wang, Yiyi; Kockelman, Kara
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-1252
• Seismic Retrofit and Ductility Enhancement of Thin-Walled Steel Tubular Bridge Piers
  Abstract: This paper deals with the seismic retrofit and ductility enhancement of thin-walled steel tubular bridge piers. The basic characteristics of the thin-walled steel tubular bridge piers are noted and the importance of various retrofit techniques in improving strength and ductility capacity of such structures is explained. A seismic design method for ultimate strength and ductility evaluation of the new and retrofitted, thin-walled, steel tubular bridge pier is presented. The application of the method is demonstrated by comparing the computed strength and ductility of some bridge piers with test results. The method is applicable for both the design of new and retrofitting of existing thin-walled steel tubular bridge piers. The effects of some important parameters such as width-to-thickness ratio, column slenderness ratio, height of infill concrete, residual stress, arrangement of additional longitudinal stiffeners and inclusion of energy absorption segment on the ultimate strength and ductility of thin-walled steel tubular bridge piers are presented and discussed.
  Authors: Mamaghani, Iraj H. P.
  Authors: Mamaghani, Iraj H. P.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 499
  Paper Number: 13-1304
• Integration of GPS Traces and Digital Elevation Maps for Improving Bicycle Traffic Simulation Behavior
  Abstract: In order to take in consideration bicycle traffic in realistic simulation, one should consider more than a simple approach based on overall average speed and acceleration. There are several different factors that should be considered, such as the diversity of people's fitness that ride bicycles on the road, the way speed varies along segments and more importantly how terrain slope influences rider's behavior.In this paper we present our approach for simulating bicycle traffic using real GPS data as source for enhancing simulation. We discuss the specific details related to the analysis process performed on a set of bicycle commuting traces, as well as the development of a custom driver behavior for VISSIM that uses statistic data taken from those bicycle GPS traces. We also propose a new methodology for considering the way slope affects bicycle traffic, as this is one of the most relevant factors related to bicycle riding.
  Authors: Henriques, Norberto; Bento, Carlos
  Authors: Henriques, Norberto; Bento, Carlos
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-1421
• Risk-Based Adaptation Frameworks for Climate Change Planning in the Transportation Sector: Synthesis of Practice
  Abstract: There is growing consensus within the scientific community that the global climate system is changing. Many of these global changes are projected to translate into regionally significant environmental impacts – including increases in precipitation, temperature, sea-level rise, and the intensity of extreme weather events. In the transportation sector, the design and management of infrastructure is heavily influenced by the surrounding environment. Thus, given the uncertain future of regional environmental conditions and climate impacts, there is concern that the design and management practices of existing infrastructure may become inadequate over the coming decades. Research institutions and government agencies in the US (e.g., the Transportation Research Board, the Federal Highway Administration), and abroad (e.g., the United Kingdom Highways Agency, New Zealand Transport) have begun to investigate adaptation strategies and evaluation frameworks for transportation infrastructure. Many of these adaptation strategies are heavily influenced by the tenets of risk analysis and risk management. This paper identifies and synthesizes several leading risk-based adaptation frameworks from the international transportation community. Specifically, we discuss these frameworks’ (1) motivations, (2) foundational risk standards/principles, (3) commonalities in their focus and approach, and (4) common barriers and limitations. Several recommendations and suggestions for future research priorities are then offered.
  Authors: Wall, Thomas A.; Meyer, Michael
  Authors: Wall, Thomas A.; Meyer, Michael
  Year: 2013
  Document Type: Paper
  Subject: Construction; Design; Environment
  Session: 509
  Paper Number: 13-1418
• Bridge Weigh-in-Motion on Steel Orthotropic Decks and Application to Bridge Assessment
  Abstract: Bridge weigh-in-motion uses an instrumented bridge as a scale to weigh vehicles. Several types of bridges may be used, if being sensitive to wheel or axle loads. Here some strains of steel orthotropic deck bridges are measured by extensometers and analyzed by software, to calculate axle loads and gross vehicle weights. Between 2009 and 2011, several large scale tests were done on the Millau viaduct (France), the tallest cable stayed bridge in the world. These tests showed that the system meets the accuracy class C(15)/D+(20) of the European WIM Specifications. The data obtained can be used for fatigue checks, because it assesses truck sizes and weights of the traffic and the behaviour of the bridge. We show here that bridge lifetimes under current and possible future traffic loads, after an increase of the GVW limit from 40 tons to 44 tons in France, could be reduced by 20%.
  Authors: Jacob, Bernard A.; Leng, Sio-Song; Schmidt, Franziska
  Authors: Jacob, Bernard A.; Leng, Sio-Song; Schmidt, Franziska
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 525
  Paper Number: 13-1452
• Context-Sensitive Approach for Network Selection of Infrastructure Transportation Projects
  Abstract: Context Sensitive Solutions aim to provide a systematic and comprehensive approach to project development from inception and planning through operations and maintenance. Its goal is to achieve a procedure that provides an outcome harmonizing transportation requirements with community needs and values. Multi Criteria Analysis can assist in the assessment of the various competing needs and provide a systematic approach in evaluating options. Merging the Context Sensitive Solutions approach and the Multi Criteria Analysis, a procedure has been implemented to select the most effective investment projects solving a classical multi-objective optimization problem under budget constraints. This paper explores this potential and identifies the required steps to be taken to allow for evaluating this concept. An example case is presented demonstrating the process and identifies future steps to be undertaken to ensure the widespread application of the process.
  Authors: Di Graziano, Alessandro; Cafiso, Salvatore; Stamatiadis, Nikiforos
  Authors: Di Graziano, Alessandro; Cafiso, Salvatore; Stamatiadis, Nikiforos
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 801
  Paper Number: 13-1459
• Evaluation of Effect of Pedestrian Crossings on Roundabout Performance Using Microsimulation
  Abstract: Most specialized manuals recommend the placement of pedestrian crossings at 10/15 meters from the roundabout carriageway, in order to minimize the pedestrian disruption on the global functioning of the intersection. Normally, this recommendation is based on empirical relationships without any scientific based studies that prove its efficiency and adequacy. In this context, this paper is focused on the analysis of the influence that the presence of different locations of pedestrian crossings has in the roundabout performance level, using microssimulation techniques. The roundabout performance level is evaluated according to two indicators: vehicle traffic flows and average travel times. The results proved interesting showing that the effect of pedestrian crossing only takes a significant influence in terms of average travel time and for high traffic and pedestrian demand levels. In spite of this it appears that the effect is more pronounced in exit section compared to the entry. For saturation levels below 70% the effect of the presence of pedestrian crossing was practically negligible, regardless of the section on analysis. It is concluded that the usual practice of locating the exit crosswalks at approximately 15 meters from the exit section seems to be an equilibrated solution, regarding the smoothness of traffic and the walking distance. However for traffic calming applications the location of pedestrian crossings near the circulatory ring delimitation seems perfectly acceptable.
  Authors: Bastos Silva, Ana; Cunha, Joana; Relvão, Tiago
  Authors: Bastos Silva, Ana; Cunha, Joana; Relvão, Tiago
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-1467
• Evaluation of Permanent Deformation Characteristics of Unbound Granular Materials from Multistage Repeated-Load Triaxial Test
  Abstract: A simple time hardening approach was used to model the accumulation of permanent deformation of unbound granular materials (UGM) in multi-stage (MS) repeated load triaxial (RLT) tests. Some of the existing permanent deformation models were used to implement this method and one model was slightly modified to better suit this approach. These models were calibrated using data from MS RLT tests on three different UGM used in base layers of flexible pavement structures. The material parameters of the models were optimized using least square curve fitting method. The shakedown ranges for each stress path of the RLT tests were calculated and the models were compared to see how well they simulate these ranges. Generally, very good fit was obtained for these models with the modified model showing the best agreement.
  Authors: Erlingsson, Sigurdur; Rahman, Mohammad Shafiqur
  Authors: Erlingsson, Sigurdur; Rahman, Mohammad Shafiqur
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 480
  Paper Number: 13-1472
• Field Performance Evaluation of Stone Interlayer Pavement in Louisiana
  Abstract: A conventional cement stabilized/treated or soil cement base (CSB) layer has been used extensively for non-interstate asphalt pavements in Louisiana to overcome problems caused by soft subgrade soil. However, due to the shrinkage in the CSB layer, cracking occurs in the base, and subsequently reflects through to the surface of the asphalt pavement. In order to reduce reflective cracking and improve the long-term performance of asphalt pavements in Louisiana, a stone interlayer between the CSB layer and the hot mix asphalt concrete (HMA) surface layer had been adopted. In this study, field performances of a stone interlayer pavement test section and cement stabilized base test control section on LA-97 in Acadia Parish, Louisiana, were monitored during 20 years of service. In addition, performances of other nine stone interlayer pavement sections in Louisiana constructed from 1999 to 2008 were monitored and evaluated. Field evaluations in this study included distress surveys on all 11 pavement sections, and nondestructive evaluation of pavement structure by the falling weight deflectometer (FWD) and the dynamic deflection determination system (Dynaflect) test on nine of those sections. The field evaluation results indicated that the stone interlayer test section on LA-97 had a superior pavement performance than the control section over the 20 years of service, and other nine stone interlayer pavement sections were in a very good pavement condition after 2.5 to 12 years of service.
  Authors: Chen, Xingwei; Zhang, Zhongjie; Lambert, Jeff
  Authors: Chen, Xingwei; Zhang, Zhongjie; Lambert, Jeff
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 239
  Paper Number: 13-1556
• Bicycle Route Choice Model That Incorporates Distance and Perceived Risk
  Abstract: In this study, we have developed a procedure to estimate bicycle link cost function parameters for use in a bicycle route choice model. A practical estimation procedure was established by formulating a bi-level optimization problem. Based on bicycle commuters’ revealed preference route choices to a university campus, a linear function with an interaction cost term was found to be the best model specification. Other models that incorporated both distance and risk terms were almost as good. Model forms that used only distance or only risk were clearly inferior, indicating the importance of using both factors. In order to investigate the relative importance of travel distance and risk concern, an elasticity ratio test was conducted. The results indicate that, for our database, travel distance is more important in route choice decisions. However, when perceived risk, as represented by link Bicycle Compatibility Index, reaches high levels, the role of the risk factor in bicycle route choice becomes almost as important as the distance factor. Bicyclists are then more likely to trade off increased distance for decreased perceived risk. The bi-level optimization method described in this paper provides a practical way to approximate bicyclist route choice behavior using a simple measure (distance) and the well-recognized Bicycle Compatibility Index. The resulting model can guide investments in bicycle facilities.
  Authors: Kang, Lei; Fricker, Jon D.
  Authors: Kang, Lei; Fricker, Jon D.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-1677
• A Physical Model Study on the Ground Settlement Caused by Tunneling in Sand
  Abstract: A physical model test on the ground settlement caused by tunneling in sand was conducted in this study. A large-scale custom-made physical model box with a lowering basement was used in this paper to simulate the tunneling. Analysis of the test results, it was found that the volume of the settlement trough was not constant and varied with the depth. An empirical equation was proposed to express the relationship between the volume of the settlement trough and the depth. Finally, a method for estimating the subsurface ground settlement of tunneling in sand was established considering the volume variation of the settlement trough with depth.
  Authors: Wang, Fei
  Authors: Wang, Fei
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: AFF60
  Paper Number: 13-1729
• Developing an Analysis Framework to Quantify and Compare Skid Resistance Performance on Porous and Nonporous Pavements
  Abstract: Porous pavement surfaces are widely used as means to improve wet-pavement skid resistance and to reduce skidding accidents. While there have been numerous studies in the literature on the ability of porous pavements in providing better skid resistance as compared to non-porous pavements, many of them are experimental in nature and could not offer a mechanistic interpretation on the skid resistance behavior exhibited by porous pavements. This paper therefore presents an analysis framework that can mechanistically quantify the amount of skid resistance available on porous and non-porous pavement surfaces and to understand the key factors involved. The analysis framework consists of two key modules. The first module determines the water film thickness accumulated on pavement surfaces for a given rainfall intensity while the second module computes wet-pavement skid resistance with consideration to structural mechanics, fluid dynamics, fluid-structure-interaction and flow within a porous medium. The developed framework is first validated against past experimental data and was found predict skid resistance accurately. An illustrative case study is then presented to quantify and compare skid resistance performance between porous and non-porous pavements. It is demonstrated through this case study that the developed framework can not only effectively compare skid resistance performances between porous and non-porous pavement surfaces, but can also provide a fundamental understanding of skid resistance development on those pavements.
  Authors: Zhang, Lei; Ong, Ghim Ping; Fwa, Tien Fang
  Authors: Zhang, Lei; Ong, Ghim Ping; Fwa, Tien Fang
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 384
  Paper Number: 13-1762
• Incorporating Saliency Map into Appraisal of Crossing Island Facilities: Drivers' Visual Attention
  Abstract: In our study, crossing island facilities are evaluated in conspicuity point of view. This paper provides an evaluation method to determine which kind of facilities can draw visual attention of driver easily with aid of saliency map. The visual scan experiment with the aid of eye tracking system was conducted to collect fixation percentage data. The evaluation method of crossing island facility was conducted based on image characteristics. The saliency-based model which based on model of visual attention built up by Ltti was set up and improved through the process of Gaussian pyramid creation, visual feature extraction and conspicuity map generation as well as the saliency map generation. Mean intensity of salient zone on the saliency map is selected as indicator to calculate fixation percentage of crossing island facility and the regression model is helpful for the evaluation of conspicuity of crossing island facility at pedestrian refuge island together with MATLAB and Photoshop.
  Authors: Xu, Zhi; Zou, Zhe; Cao, Bohu; Gong, Xiangxing
  Authors: Xu, Zhi; Zou, Zhe; Cao, Bohu; Gong, Xiangxing
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-1724
• Framework for Determination of Load Equivalencies Using DARWin-ME
  Abstract: This paper presents a methodology for determination of load equivalencies for different axle configurations and loads using mechanistic-empirical design procedures. The focus was on oversize/overweight (OS/OW) vehicles. The study uses the DARWin-ME system for pavement analysis and computation of Equivalent Damage Factors (EDF). In the context of this study, the EDF for a given axle load and configuration consists of two partial factors: Axle Load Factor (ALF) and Group Equivalency Factor (GEF). The framework adopted in this study defines a given axle load and configuration as equivalent to a reference axle load, as based on equivalent pavement responses that result in the same distress level. The study uses a modular approach to determine the EDF for different vehicle configurations. The load equivalency for a given truck configuration is equal to the sum of the EDF of its constituent axles. To that effect, the EDFs for single, tandem, tridem, and quad axles were evaluated over a wide spectrum of varying loads using three different failure criteria: rutting, fatigue cracking, and roughness. This approach provided the basis for developing the models for predicting the EDF of any given axle configuration for any given load.With the exception of rutting, the research yielded no strong evidence suggesting that the EDFs are affected by the structural capacity of the pavement sections. For single axles, however, the structural capacity had an inverse relationship with the EDFs, which suggests that thicker pavement structures are less sensitive to traffic loads. In the case of tandem, tridem, and quad axles, the relationship was non-monotonic, with the EDFs reaching their peak for structural numbers between 3.5 and 4.0. In the case of fatigue cracking, even though the structural number did not clearly influence the EDFs, a linear relationship exists between the ALF and the number of axles per axle group. Finally, in the case of roughness, the EDFs did not show any systematic trend for different structural numbers, which led the researchers to propose an average ALF that is independent of the axle group or the structural capacity of the pavement section.
  Authors: Banerjee, Ambarish; Prozzi, Jorge A.; Buddhavarapu, Prasad N. V. S. R.
  Authors: Banerjee, Ambarish; Prozzi, Jorge A.; Buddhavarapu, Prasad N. V. S. R.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 242
  Paper Number: 13-1770
• Safety Evaluation of Traffic Operation Environment in Freeway Tunnels
  Abstract: It is obvious that the operation safety in freeway tunnel is significant, after the tremendous freeway tunnel accidents in China over the past decade. With the aim to evaluate the safety of freeway tunnel operation, a matter-element and extension evaluative (AEE) model on the basis of the extenics is proposed. As the evaluation indicators are changeable, it is critical to compose risk indicators by a large evaluation indicator system. The Delphi Method (DM) is used to execute a sensitivity analysis of the indicator system, and the AHP method is used to determine the weight of the evaluation index system, considering the experts¡¯ knowledge and experience as well as the data itself implies. At the end, the value of eigenvalue in the freeway tunnel operating environment is obtained, the results indicate that the indicator system and weights are reasonable. The research results can provide a theoretical guidance for the analysis and evaluation of the tunnel operating environment.
  Authors: ZHOU, Jibiao; CHEN, Hong; LI, Xiaowei; ZHANG, Long; GAN, Zuoxian
  Authors: ZHOU, Jibiao; CHEN, Hong; LI, Xiaowei; ZHANG, Long; GAN, Zuoxian
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 727
  Paper Number: 13-1274
• Methodology for Evaluating Climate Change Impact on Asphalt Pavement Design Life
  Abstract: A methodology to evaluate the impact of climate change on asphalt pavement design life has been developed by linking together a pavement performance model and an innovative climate model. The DARWin-ME software, based on the Mechanistic-Empirical Pavement Design Guide, has been used to predict changes in pavement performances. The national model Meteonorm 7.0, based on the combination of 18 general circulation models and a stochastic approach for regional modeling, has been applied as climate model.The methodology has been applied to Swiss specific road conditions, by combining different climate and site specific characteristics (pavement, traffic, subgrade, climate region, etc.). The results have permitted to evaluate, in a first step, current asphalt pavements for future climate conditions in terms of change in their predicted design life. In a second step, current asphalt pavements have been adapted by changing their characteristics in order to reach recommended design life. Finally, recommendations and guidelines on adapting current road infrastructures for the future have been exposed. This article focuses solely on results from the first step of the methodology.
  Authors: Rychen, Patrick; Carter, Alan; Dumont, Andre-Gilles
  Authors: Rychen, Patrick; Carter, Alan; Dumont, Andre-Gilles
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Pavements
  Session: 660
  Paper Number: 13-1337
• Examination of Distracted Driving and Yellow Light-Running: Analysis of Simulator Data
  Abstract: Driving on an approach to a signalized intersection while distracted is particularly dangerous, as potential vehicular conflicts and resulting angle collisions tend to be severe. Given the prevalence and importance of this particular scenario, the decisions and actions of distracted drivers during the onset of yellow lights are the focus of this study. Driving simulator data were obtained from a sample of 58 drivers under baseline and handheld mobile phone conditions at the University of Iowa - National Advanced Driving Simulator. Explanatory variables included age, gender, cell phone use, distance to stop-line, and speed. Although there is extensive research on drivers’ responses to yellow traffic signals, the examination has been conducted from a traditional regression-based approach, which does not necessary provide the underlying relations and patterns among the sampled data. In this paper, we exploit the benefits of both classical statistical inference and data mining techniques to identify the a priori relationships among main effects, non-linearities, and interaction effects. Results suggest that novice (16-17 years) and young drivers’ (18-25 years) have heightened yellow light running risk while distracted by a cell phone conversation. Driver experience captured by age has a multiplicative effect with distraction, making the combined effect of being inexperienced and distracted particularly risky. Overall, distracted drivers across most tested groups tend to reduce the propensity of yellow light running as the distance to stop line increases, exhibiting risk compensation on a critical driving situation.
  Authors: Haque, Md. Mazharul; Ohlhauser, Amanda D.; Washington, Simon; Boyle, Linda Ng
  Authors: Haque, Md. Mazharul; Ohlhauser, Amanda D.; Washington, Simon; Boyle, Linda Ng
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 544
  Paper Number: 13-1710
• Clustering of Pavement Stretches and Determining OptimumNumber of Clusters for Pavement Maintenance
  Abstract: When a large number of pavement stretches are to be maintained, the decision making becomes complicated and prioritization of individual stretches is not much useful in taking maintenance management decisions. In such situations grouping or clustering the pavement stretches having similar distress characteristics would be the practical and effective approach. Since a number of distresses are observed on pavements and usually they are being represented in different levels of severity and extent it becomes quite difficult to cluster them. The problem becomes further aggravated as the weights of various distresses also play an important role and it is difficult toexpress them objectively. A methodology has been suggested in this paper on the clustering of pavement stretches and also to find out the optimum number of clusters. The technique has been explained with the help of a case study carried out in a few selected stretches in the state of Rajasthan, India.
  Authors: Sarkar, Ashoke Kumar; Sandra, Amarendra Kumar
  Authors: Sarkar, Ashoke Kumar; Sandra, Amarendra Kumar
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 662
  Paper Number: 13-1475
• Prediction of Capacity for Roundabouts Based on Percentages of Trucks in Entry and Circulating Flows
  Abstract: The objective of this study is to develop the method of adjusting gap acceptance parameters for trucks to estimate capacity at roundabouts. Since driver¡¯s gap acceptance behavior is not only affected by trucks in the entry flow, but also trucks in the circulating flow, critical headways were separately estimated for various combinations of vehicle types in the circulating flow at 11 roundabouts in Ontario, Vermont and Wisconsin. Since truck percentage is different in different entry leg, the critical headways and follow-up times were estimated at each leg separately. The variation in gap acceptance behavior was also observed at one of the eleven roundabouts for 13 consecutive days to evaluate statistical significance of difference in the behavior between two entry legs. The results show that the new adjusted critical headway improved the accuracy of capacity estimation, and the critical headways were significantly different between the two legs with different truck percentages in the entry flow. The study provides an insight into how to capture the effect of trucks on roundabout capacity.
  Authors: Lee, Chris; Khan, Moayed Naeem
  Authors: Lee, Chris; Khan, Moayed Naeem
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-1391
• Is Scientific Evidence in Practice? Review of Driver and Cyclist Education Materials with Respect to Cycling Safety Evidence
  Abstract: Introduction: Countries with high cycling rates have national, school-based, mandatory cycling education programs whereas in North America cycling education is diverse and disparate. The aim of this research was to understand what cycling safety content is delivered in Canadian jurisdictions and how training materials align with scientific evidence.Methods: Cycling safety literature was reviewed and cycling education materials were compiled from drivers’ licensing and cyclist education programs. The education materials were compared with the evidence to determine where there were agreements, disagreements or gaps. Results: 56 scientific articles focused on crash or injury risk, injury severity, or other safety outcomes and met our inclusion criteria. The evidence covered bicycling operations, visibility and safety gear, road characteristics, route types, and bicycle-motor vehicle interactions. 48 training materials for cyclists and/or drivers were gathered from 12 provincial and territorial driver’s licensing jurisdictions, 5 municipalities, and 7 advocacy organizations. Broadly, the materials covered topics of bicycle fit and maintenance, rules of the road, in addition to the topics included in the safety literature. Some of the education items were supported by evidence, although many were related to legislation or common sense. Evidence on motor vehicle passing distances conflicted with the guidance about where to cycle on the road. A gap in the educational materials was the relative safety of different route infrastructure, important for route planning.Conclusions: This research illustrates the diversity of cycling education in Canada and suggests areas where education materials could be modified to align with scientific evidence on safe cycling.
  Authors: Winters, Meghan; Weddell, Angie; Teschke, Kay
  Authors: Winters, Meghan; Weddell, Angie; Teschke, Kay
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-1534
• Global Sensitivity Analysis of Mechanistic-Empirical Pavement Performance Predictions for Flexible Pavements
  Abstract: The new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) provides pavement analysis and performance predictions under various feasible design scenarios. The MEPDG performance predictions for the anticipated climatic and traffic conditions will depend on the values of the input parameters that characterize the pavement materials, layers, design features, and condition. This paper focuses on comprehensive global sensitivity analyses (GSA) of flexible pavement performance predictions to MEPDG design inputs under five climatic conditions and three traffic levels. Design inputs evaluated in the analyses include traffic volume, layer thicknesses, material properties, groundwater depth, geometric parameters, and others. Correlations among design inputs were considered where appropriate. The GSA varied all design inputs simultaneously across the entire problem domain for each of the 15 base cases (5 climates x 3 traffic levels). Two response surface modeling (RSM) approaches, multivariate linear regressions (MVLR) and artificial neural networks (ANN or NN), were developed to model the GSA results for evaluation of design input sensitivities across the entire problem domain. The ANN-based RSMs for MEPDG flexible pavement performance predictions not only provide robust and accurate representations of the complex relationships between design inputs and distress outputs but also capture the variation of sensitivities across the problem domain. The design limit normalized sensitivity index (NSI) adopted for this study provides practical interpretation of sensitivity relating a given percentage change in a design input to the corresponding percentage change in predicted distress relative to its design limit value.
  Authors: Schwartz, Charles W.; Li, Rui; Ceylan, Halil; Kim, Sunghwan; Gopalakrishnan, Kasthurirangan
  Authors: Schwartz, Charles W.; Li, Rui; Ceylan, Halil; Kim, Sunghwan; Gopalakrishnan, Kasthurirangan
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 318
  Paper Number: 13-1572
• Transportation Applications for Mobile Lidar Scanning:State-of-the-Practice Questionnaire
  Abstract: The relatively recent emergence of mobile Light Detection and Ranging (LIDAR) technologies as a potentially transformative tool for numerous transportation engineering applications coupled with a lack of existing standards has resulted in the need for an improved understanding of how this technology is currently being implemented, and what challenges are limiting its adoption. To that end, a questionnaire was administered to State Departments of Transportation (DOTs) to document and evaluate the state-of-the-practice regarding mobile LIDAR in transportation applications. Representatives from each of the 50 U.S. states and 6 additional transportation agencies completed the questionnaire, for a total of 74 responses. A second service provider questionnaire was completed by 14 companies experienced with mobile LIDAR services. Interestingly, it was determined that more DOTs have used mobile rather than airborne LIDAR services in the last year, even though mobile scanning is a less established technology. Additionally, the results showed that DOTs perceive cost to be one of the most significant challenges to the adoption of mobile LIDAR, indicating that more evidence and education are required regarding benefit to cost comparisons of the technology. The questionnaire also revealed current struggles as DOTs transition from two- to three-dimensional workflows and modeling. These questionnaires established a technology adoption baseline that can be used to measure future progress and provide the foundation for national guidelines currently under development.
  Authors: Hurwitz, David S.; Tuss, Halston; Olsen, Michael James; Roe, Gene; Knodler, Michael A.
  Authors: Hurwitz, David S.; Tuss, Halston; Olsen, Michael James; Roe, Gene; Knodler, Michael A.
  Year: 2013
  Document Type: Paper
  Subject: Construction; Data and Information Technology; Design
  Session: 582
  Paper Number: 13-1606
• Evaluation of Functional Properties of Porous Asphalt Pavements Subjected to Clogging and Densification of Air Voids
  Abstract: This study was motivated by concerns that porous asphalt concrete (PAC) might not perform well under the environmental and traffic conditions. It was feared that the drainability, friction, and noise benefits of PACs would be rapidly lost. PAC sections were constructed by using three different types of asphalt as follows: non-modified bitumen (NMB), polymer-modified bitumen (PMB), and highly-modified bitumen (HMB). These sections were completed in 2008 and evaluated twice per year for their functionality. Clogging and densification were shown to be the main reason to cause reduction in air voids of PAC. For the NMB and PMB sections, more than 70% of reduction in air voids resulted from traffic compaction, while less than 30% for the HMB section. The decrease in drainability corresponded well with the decrease in air voids. Cleaning PAC mixtures did not appear to be effective for the NMB and PMB sections since most reduction in air voids resulted from traffic compaction. Because of the significant amount of macrotexture produced within PAC pavement surfaces, PAC layers maintained adequate frictional characteristics even after become clogged and condensed. The noise characteristics of PAC depended on the air void content. No rutting, raveling, cracking or other failures have been observed on the three monitored sections to any significant extent since open to traffic in 2008, which suggests that PAC may be a viable pavement surface type for use on highways to provide good performance, including good friction, reduced splash and spray, and reduced tire¡Vpavement noise.
  Authors: Chen, Jian-Shiuh; Hsieh, Weichou; Liao, Min-Chih
  Authors: Chen, Jian-Shiuh; Hsieh, Weichou; Liao, Min-Chih
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 711
  Paper Number: 13-1623
• Measuring and Analyzing Driver's Perception-Reaction Time to Green Phase Based on Digital Image Processing
  Abstract: A method based on digital image processing for measuring drivers¡¯ perception-reaction time (PRT) to the green phase is proposed. The detection of the onset of a green signal is based on the RGB color model. The detection of the start of the vehicle is based on the frame difference. The driver¡¯s perception-reaction time (PRT) is equal to the difference between the frame of the onset of the green signal and the frame of the start of the vehicle divided by the video frame rate. Normal, Lognormal, Gamma and Weibull distributions are used to fit the PRT data. The Chi-Square goodness-of-fit test is conducted to determine how well the distributions fit to the sample data. The results show the Weibull distribution appears to best fit the PRT to the green phase. The fuzzy c-means clustering is utilized for PRTs classification. The PRTs are classified into five classes: ¡°Very fast¡±, ¡°Fast¡±, ¡°Moderate¡±, ¡°Slow¡± and ¡°Very slow¡±. The five clustering centers, which are the typical value of ¡°Very fast¡±, ¡°Fast¡±, ¡°Moderate¡±, ¡°Slow¡± and ¡°Very slow¡±, can be regarded as reference values of drivers¡¯ starting response for microscopic traffic simulation software. The results also show the PRT to the green phase is higher than the brake PRT because of the different urge for the response, limb motion and operation.
  Authors: Li, Zhenlong; Rong, Jian
  Authors: Li, Zhenlong; Rong, Jian
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 550
  Paper Number: 13-1624
• Limit Analysis for Historic Masonry Bridge with CFRP Reinforcements
  Abstract: This paper deals with the collapse behavior of a historical masonry arch bridge subject to combined seismic loads, by means of the limit analysis and shakedown theorems. A finite element modal analysis and seismic load evaluation was performed building a program code. The assessment of the collapse loads and shakedown multiplier, consisting of corresponding nonlinear constrained optimization problems, were analyzed using lower bound theorems of the limit analysis and shakedown theory, respectively. Because the retrofitting of this structure cannot be performed in the intrados surface, the application of CFRP strips on the extrados of the arch is a useful and valuable technique, as shown by a significant increase of the limit and shakedown multipliers.
  Authors: Gesualdo, Antonio; Catalani, Giulio
  Authors: Gesualdo, Antonio; Catalani, Giulio
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Materials
  Session: 300
  Paper Number: 13-1658
• Modeling the Impact of Energy Trafficon Local Unpaved Roads
  Abstract: Laramie County was selected in accordance with the legislative directive as part of a project to determine the impact of the oil and gas industry on county roads. This paper takes into account the impact gravel roads. With a lacking road and bridge budget, Laramie county is only just keeping up with this impact. In order to receive additional funding from the state legislature, actual impact needs to be assessed. The different distresses and ride quality of all the county gravel roads showed that, on average, the roads were in good condition, no matter the level of impact. However, the cost to keep the impacted roads in this condition came at a much greater price. By modeling the characteristics of the gravel roads in Laramie County, a better understanding of the degradation taking place and the main causes were examined. This was done in hopes that the information from this model will then be used for more efficient maintenance strategies and a more cost effective use of the county’s budget so that the county may continue to keep up with the energy impact. The processed developed in this study is very useful for other local agencies impacted by energy development.
  Authors: Stroud, Nathan; Ksaibati, Khaled
  Authors: Stroud, Nathan; Ksaibati, Khaled
  Year: 2013
  Document Type: Paper
  Subject: Design; Maintenance and Preservation; Pavements
  Session: 240
  Paper Number: 13-1702
• Impact Conditions Associated with Cable Median Barrier Failures
  Abstract: Cross-median crashes are disproportionately represented with respect to fatalities on divided roadways. Many state DOTs seeking to mitigate cross-median crash risk installed cable median barriers, due to their versatility, flexibility, and low cost. However, cable median barriers are also roadside hazards. Conditions associated with cable median barrier containment failures and crash severity were investigated in this study. The 85th percentile trajectory angle associated with severe cable median barrier crashes was calculated to be 39 degrees. Severe median crashes frequently occurred with larger orientation angles than trajectory angles. Although high-tension cable median barriers have many advantages over low-tension systems, low-tension systems had the lowest severe crash rate of 1.7% despite penetration and rollover rates of 9.1% and 7.8%, respectively. Individual distributions of penetration and rollover crashes were not statistically different when compared by vehicle classification. Thus, vehicle make, model, and type may be equally important in full-scale crash testing as test vehicle weight and CG height. Future cable median barrier tests should be conducted at a CG trajectory angle of 39 degrees with large car and SUV vehicles to maximize safety potential of these systems. With these changes to full-scale test procedures, cable median barrier containment failure rates would decrease and many lives would be saved.
  Authors: Stolle, Cody Steven; Sicking, Dean L.
  Authors: Stolle, Cody Steven; Sicking, Dean L.
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-1564
• Analyzing Bicyclists’ Choices of Bicycle Facility Type Using a Random-Parameter Probit Model
  Abstract: When allocating limited funds to bicycle facilities, it would be helpful to know the extent to which a new facility will be used. If a bicycle lane is added to a street, how many bicyclists will no longer use the sidewalk? If a separate bicycle path is constructed, how many bicyclists will move from the street or sidewalk? Bicyclists were interviewed at the end of their trips and asked which part of the cross-sections along their routes they had used – on-street or off-street. This study developed a random-parameter probit model to analyze the bicyclists’ facility preferences and capture the unobserved heterogeneity across the population. This model was found to be superior to a standard binary probit model and a random effects model. Sidewalk width, traffic signals, segment length, road functional class, street pavement condition, and one-way street configuration were found to be statistically significant. The compound effects of multiple variables were demonstrated by varying sidewalk width and Bicycle Compatibility Index. The results suggest that merely adding a bicycle lane does not guarantee that a significant proportion of bicyclists will switch to it. Lessons also can be drawn from marginal effects and elasticity to indicate where a particular bicycle facility would be most compatible with bicyclists’ revealed choices.
  Authors: Kang, Lei; Fricker, Jon D.
  Authors: Kang, Lei; Fricker, Jon D.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-1676
• Sigmoid Distress Prediction Models at Project Level for Main Urban Flexible Pavements Based on Historical Data
  Abstract: The development of distress prediction models for overlaid flexible main street pavements in large municipalities cross Saudi Arabia is described. The sigmoid of models represented quantitatively predict distress density versus pavement age and are based on pavement condition data maintained by the General Directorate of Operation and Maintenance (GDOM) at the Municipality of Riyadh city, Jeddah city, Makkah holy city, Madinah city, and Damam city. Different model forms of the sigmoid family were examined in an attempt to identify the most appropriate one for fitting the data. Models are available for the following distress types in flexible main street pavements: Block Cracks, Longitudinal and Transverse Cracking, Patching, Potholes, Depressions, Weathering and Raveling, and Cracking (due to patching). The seven models have been developed using more than 11 years survey data for overlaid sections on the road network of Riyadh, Jeddah, Makkah, Madinah, and Damam. In all prediction models, age is by far the most significant predictor of deterioration. The traffic volume in terms of Annual Daily Traffic (ADT) and the drainage play only a secondary role in forecasting prediction of distress propagation. In general, the developed models provided an
  Authors: Mubaraki, Muhammad; Thom, Nick
  Authors: Mubaraki, Muhammad; Thom, Nick
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-1803
• Analysis of Sight Distance, Crash Rate, and Operating Speed Relationships for Single-Lane Roundabouts in the United States
  Abstract: This paper seeks to determine whether a relationship exists between sight distance parameters, crash rates and operating speeds at low volume single lane roundabouts in the United States (US). Establishing an understanding of the interaction of design, operations, and crash performance would be a step forward in the development and application of performance-based standards for roundabouts. As part of the specific objective of this paper, research was done to quantify the relationship between crash rates, sight distance parameters and operating speeds based on crash, traffic and geometric data from 72 approaches to 19 single lane roundabouts in six states. The data for these sites were broken into two groups based on the posted speed limit. The research findings provided insight into the operational and safety effects of sight distance geometry at roundabouts. This research also identified a methodology that provides guidance as to the development of performance-based standards which rely on a better understanding of those relationships. In general, these findings were consistent with previously conducted studies and indicated that exceeding sight distance thresholds increases the risk of crash occurring. It was also found that exceeding sight distance thresholds yielded greater speed differentials between the approach and the entry to these roundabouts. This research methodology and corresponding results can advance the state of practice closer towards understanding the relationships of sight distance design attributes-operational characteristics and safety metrics for low volume single lane roundabouts which is necessary to in the creation of performance-based standards.
  Authors: Zirkel, Brian; Park, Seri; McFadden, John; Angelastro, Michael; McCarthy, Leslie Ann
  Authors: Zirkel, Brian; Park, Seri; McFadden, John; Angelastro, Michael; McCarthy, Leslie Ann
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-1847
• PERFORMANCE OF FRP CONCRETE BEAMS EXPOSED TO SEVERE ENVIRONMENTS
  Abstract: The use of various forms of fiber reinforced polymers (FRP) has been on the increase in numerous construction applications. This includes internal reinforcement of Portland cement concrete by rods as well as strengthening concrete elements by laminates. However, there is little work conducted on concrete involving various combinations of FRP composites. Also, there is a need to better understand the behavior of FRP systems in concrete elements subjected to chemicals and to external heat. This study aims at investigating the flexural strength rendered by FRP rods and FRP external laminates mounted on concrete beams. Sets of beams were made with reinforcing steel, FRP rods and FRP laminates and were subjected to 3, 6 and 9 week cycles in fresh water, sea water and 20% magnesium sulphate as well as 6-hour exposure to temperatures of 80 and 150 0C. The flexural load was assessed for all beams prior to and after exposure cycles. The results of this work reveal that FRP smooth rods did not provide the anticipated reinforcement effect, likely due to a lack of bonding. The FRP laminates, however, contributed to a large increase in flexural strength particularly when used in conjunction with steel reinforcement. Sea water and 150 0C temperature caused the largest loss in flexural strength. It is recommended to use protective mortar layers to alleviate heat-induced loss of flexural strength. For future work, other sets of materials, FRP combination as well as exposure schemes need to be evaluated.
  Authors: Abou-Zeid, Mohamed Nagib; Agaiby, Michael G.; El-Deeb, Tarek; El-Said, Sherif; Georgy, Fadi; Zaki, Amr
  Authors: Abou-Zeid, Mohamed Nagib; Agaiby, Michael G.; El-Deeb, Tarek; El-Said, Sherif; Georgy, Fadi; Zaki, Amr
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Materials
  Session: 300
  Paper Number: 13-1833
• Comparison of Isotropic and Cross-Anisotropic Analysis of Pavement Structures
  Abstract: In most existing pavement design methods, including South African Mechanistic Design Method (SAMDM), pavements are analyzed using linear elastic multilayer theory. In this approach, it is assumed that isotropic conditions are present in the structural layers of the pavement section. There are however numerous researchers that disagree with this statement and their research have proven that there are inherent and induced anisotropic material behaviors in the structural layers of a pavement section. The problem facing the SAMDM is that this anisotropic behavior of material may reduce the predicted life of pavement sections as described in the South African Technical Recommendations for Highway (TRH 4). The objective of this study was to determine if cross-anisotropic conditions induced in the pavement layer reduced the predicted life resulting in gross overestimation of the SAMDM in South Africa. During this study pavements were analyzed using cross-anisotropic conditions in the layers. The results from the analysis showed that the asphalt surfacing layer is very sensitive to cross-anisotropic conditions. The tendency is to reduce the predicted life drastically with any variation of stiffness modulus relative to each direction. The granular layer tends to reduced predicted life resulting in overestimation of current values in the TRH 4. The cemented layers show some increase in predicted life in the cemented phase but an overall tendency in decreased predicted life. The main conclusion evident from each layer is that the current design method in the SAMDM must include cross-anisotropic analysis to achieve more realistic values of predicted life for pavement sections.
  Authors: Steyn, Wynand Jacobus van der Merwe; Maina, James William; Repsold, Anton
  Authors: Steyn, Wynand Jacobus van der Merwe; Maina, James William; Repsold, Anton
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 480
  Paper Number: 13-1871
• Comprehensive Three-Dimensional Methodology for Design, Assessment, and Checking Process of Rural Roads
  Abstract: The planning and approval process for rural roads takes place in Germany iteratively within various design stag-es, each with a subsequent approval process. This gives rise to planning and approval times of approx. 15 - 20 years before a rural road is completed. A new kind of multi-stage methodology is currently being developed as part of a research project for the design, assessment and testing process for rural roads. Following the three-dimensional design in real time (stage 1) with an iterative 3D model at a special design workstation, a new kind of procedure with a sectoral power wall, a multi-functional box and special interactive tools are available for the assessment process in stage 2. As a result, it is possible to illustrate the assessment and decision processes in a better way and make everything clearer. After optimizing the route as a result of the assessment process, the subsequent stage 3 provides a quality check to integrate the route in its surroundings with the help of augmented reality tools – i.e. reality is cross-faded with virtual graphics. A real motion path can be selected or individual positions for the virtual cross-fading process. The theoretical principles for the individual stages in the compre-hensive methodology and the crucial hardware and software tools are available as prototypes for initial practical tests. The results obtained will flow directly into the optimization and validation of the comprehensive methodology.
  Authors: Kuehn, Wolfgang; Kubik, Ronny; Leithoff, Ingolf
  Authors: Kuehn, Wolfgang; Kubik, Ronny; Leithoff, Ingolf
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 679
  Paper Number: 13-1990
• Evaluating Pavement Condition of National Highway System
  Abstract: The Federal highway Administration (FHWA) recently conducted a study to identify a means to evaluate health of the interstate highway system with a specific focus on pavements and bridges. One important component of any statement of health is the condition of the pavement, which is the focus of this paper. A set of six potential metrics were reviewed using data on an 874-mile long corridor of I-90 as a potential means for evaluating pavement condition in terms of good/fair/poor across the interstate network. Metrics reviewed included both functional and structural pavement condition. The study concludes that currently the International Roughness Index (IRI) provides the most consistent method for evaluating ride quality condition. Other metrics pursued using distress or structural condition are not currently suitable as nationwide condition measures and will require further work before these can be implemented for routine use.
  Authors: Simpson, Amy; Rada, Gonzalo R.; Visintine, Beth; Groeger, Jonathan
  Authors: Simpson, Amy; Rada, Gonzalo R.; Visintine, Beth; Groeger, Jonathan
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 780
  Paper Number: 13-2027
• Effect of Asphalt Oxidation on Performance of LTPP SPS-9A Sections in Connecticut
  Abstract: Six asphalt pavement test sections were constructed in 1997 on Route 2 in Connecticut to conduct the Special Pavement Study (SPS-9A) experiment under the Long Term Pavement Performance (LTPP) program. The SPS-9A experiment lasted 12 years and targeted comparison of long-term performance of SuperPave and Marshall mixes modified with recycled asphalt pavement (RAP). This paper analyses differences in post-termination distresses and structural capacity in the LTPP SPS-9A sections as related to their asphalt oxidation level after 12 years of service. The distress data was retrieved from videologs collected by an Automated Road Analyzer, while structural capacity was evaluated by elastic moduli backcalculated from deflections measured by a Falling Weight Deflectometer. The oxidation levels were measured by a portable infrared spectrometer on the pre-stored original binders and those extracted from the cores. In addition, direct infrared measurements on asphalt mixtures from the top of the cores were conducted. On average, all RAP-modified mixes yielded lower elastic moduli than non-modified ones. In addition, RAP-modified SuperPave mixes shown higher severity of surface cracking and very high level of weathering. The difference in the effect of RAP on structural integrity and distress performance of Superpave and Marshal mixes was attributed to aging susceptibility of their binder components.
  Authors: Yut, Iliya; Zofka, Adam
  Authors: Yut, Iliya; Zofka, Adam
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 377
  Paper Number: 13-2032
• Crash Characteristics of Pedestrian Fatalities: Comparison of China and the United States
  Abstract: Collisions between pedestrians and motor vehicles are the unfortunate part of modern life, and their outcome is often tragic and costly. This study focuses on the crash characteristics and factors associated with pedestrian¡¯s collision with motorized vehicles. Firstly, this paper provides a thorough review of previous literatures in the field of pedestrian safety. Then, a comparison analysis between pedestrian crash data in China and the US is proposed. Results of the crash data statistics show that the total number of traffic crashes follow the same decline trends in the two countries, and the total number of traffic fatalities in the US is about one half of that in China. Compared to other road users, drivers account for the largest fatality proportion in the two countries. The second largest group of death in traffic accidents is vehicle passenger in the United States but pedestrian in China. Furthermore, in terms of the factors related to pedestrian crashes, conclusions about gender, age and improper behavior factor are drawn from the pedestrian crash data analysis. Based on these key findings, this paper addresses some potential countermeasures and strategies that aim at improving pedestrian safety.
  Authors: Zhou, Zhuping; Ren, Gang; Wang, Wei; Qizhou, Hu; Li, Haiyuan
  Authors: Zhou, Zhuping; Ren, Gang; Wang, Wei; Qizhou, Hu; Li, Haiyuan
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-2036
• Safety Issues in Design of Dual Right-Turn Lanes
  Abstract: This study is to investigate safety issues in the design of dual right-turn lanes. Historical crash records at 19 dual right-turn lanes were collected and analyzed to identify the contributing factors to different types of right-turn related crashes. In addition, the historical crash records for the dual right-turn lanes were compared to those for single right-turn lanes with similar traffic conditions. Based on the results of this study, several issues in the design of dual right-turn lanes were identified and recommendations for improvements were provided. It was found that dual right-turn lanes that are well designed do not cause more crashes than single right-turn lanes. This study can help traffic engineers to better design and implement dual right-turn lanes
  Authors: Qi, Yi; Wang, Yubian; Chen, Xiaoming
  Authors: Qi, Yi; Wang, Yubian; Chen, Xiaoming
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 222
  Paper Number: 13-2071
• Development of Improved and More Effective Dynamic Modulus E* Model for Mixtures in Costa Rica by Means of Artificial Neural Networks
  Abstract: Various dynamic modulus (E*) predictive models have been developed to estimate E* as an alternative to laboratory testing. The most widely used model is the 1999 I-37A Witczak predictive equation based on North American mixtures laboratory results. The differences in material properties, traffic information, and environmental conditions for Latin American countries make it necessary to calibrate these models using local conditions. Consequently, the National Laboratory of Materials and Structural Models at the University of Costa Rica (in Spanish, LanammeUCR) has previously performed a local calibration of this model based on E* values for different types of Costa Rican mixtures. However, further research has shown that there is still room for improvement in the accuracy of the calibrated model (Witczak-Lanamme model) based on advanced regression techniques such as artificial neural networks (ANN). The objective of this study was to develop an improved and more effective dynamic modulus E* predictive regression model for mixtures in Costa Rica by means of ANN based models. A comparison of the predicted E* values among the Witczak model, Witczak-Lanamme model and the new and improved model based on artificial neural networks (ANN-Lanamme model) indicated that the former not only met the model adequacy checking criteria but also exhibited the best goodness of fit parameters and the lowest overall bias. The findings of this study also supported the use of more advanced regression techniques that can become a more attractive alternative to local calibration of the Witczak I-37A equation.
  Authors: Leiva-Villacorta, Fabricio; Loria-Salazar, Luis; Aguiar-Moya, José Pablo
  Authors: Leiva-Villacorta, Fabricio; Loria-Salazar, Luis; Aguiar-Moya, José Pablo
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 554
  Paper Number: 13-2176
• Evaluating Bicycle Infrastructure: Assessment of Three Alternative Quality-of-Service Metrics
  Abstract: Cities throughout the United States are increasingly interested in designing bicycle facilities to attract new riders and improve the comfort of existing riders. In particular, transportation agencies increasingly use treatments such as cycle tracks, buffered bike lanes, and colored pavement to supplement or replace traditional facilities (e.g., bike lanes). To respond to this trend, transportation professionals require evaluation metrics that effectively assess design options and provide decision-support in choosing bicycle facilities that best match local context. Recent research has produced several bicycle evaluation tools (e.g., bicycle Level of Service) that attempt to fill this need. This paper presents the results of a comprehensive real-world comparison of three leading bicycle evaluation tools: 2010 Highway Capacity Manual Bicycle Level of Service (BLOS); Danish Road Directorate BLOS; and San Francisco's Bicycle Environment Quality Index (BEQI). Each evaluation tool was applied to a before-after evaluation of two bicycle facility installations in Washington, DC. The tools were assessed using a consistent set of evaluation criteria including: data and time requirements; sensitivity to key inputs; intuitiveness of the results; and soundness of the tool’s theoretical basis. Intercept surveys of facility users were used to compare the tool outputs to actual user preferences. Results suggest several shortcomings with the HCM BLOS methodology that make it unsuited to assessing bicycle design options that include cycle tracks and other emerging bicycle facility types. Additional research is needed to develop a nationally accepted bicycle evaluation tool to reflect the growing variety of bicycle facilities in the United States.
  Authors: Parks, Jamie; Tanaka, Alison; Ryus, Paul; Monsere, Christopher M.; McNeil, Nathan Winslow; Goodno, Mike
  Authors: Parks, Jamie; Tanaka, Alison; Ryus, Paul; Monsere, Christopher M.; McNeil, Nathan Winslow; Goodno, Mike
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-2191
• Performance Evaluation of Permeable Friction Courses in Texas
  Abstract: The use of permeable friction course (PFC) pavements is very common in Texas, the United States, and other countries. Some of the benefits of using PFCs include pavement noise reduction, enhanced safety by improved drainability and subsequent reduction in splash and spray during wet weather, and better ride quality. In the current study, performance of different PFC sections in Texas is evaluated over a period of four years in terms of functionality, durability, and safety. Findings from this study indicate that PFC sections performed better as compared to reference hot mix asphalt sections in terms of texture and friction, achieving the goal of providing a safer ride surface. The overall performance of PFCs through time was satisfactory, although certain field sections exhibited failures such as loss of drainability, raveling, and changes in friction. This paper discusses the causes of these failures and provides recommendations to prevent reoccurrence in subsequent projects.
  Authors: Arambula, Edith; Garcia Cucalon, Lorena; Valluri, Divya; Martin, Amy Epps; Estakhri, Cindy K.
  Authors: Arambula, Edith; Garcia Cucalon, Lorena; Valluri, Divya; Martin, Amy Epps; Estakhri, Cindy K.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 552
  Paper Number: 13-2239
• Sound Absorption and Friction Responses of Nano-Concrete for Rigid Pavements
  Abstract: This paper mainly reports on the influence of nanosilica on friction and sound absorption responses of concrete for application in rigid pavements. The feasibility of applying the nano-lotus leaf as a coating for concrete material is also discussed in this paper. Previous research on friction and sound absorption characteristics of concrete pavement mostly emphasized creating different surface textures through macrotexture modifications. The microstructure can also have significant effect on the surface texture, friction and sound absorption characteristics of concrete. This research studied the friction and sound absorption properties of concrete based on the microtexture modification using nano-materials such as nanosilica and nano-lotus leaf.Several laboratory concretes were produced using different proportions of nanosilica, which was used as a partial replacement of cement by weight. The fresh concretes were tested for workability, wet density, and air content. The hardened concretes were tested for compressive strength, friction and sound absorption. The British pendulum test was used to determine the friction number. The sound absorption coefficient was determined using an impedance tube. Preliminary results indicate that nanosilica can increase friction and sound absorption of concrete pavements. Also, the results show that the nano-lotus leaf can be applied as a coating on concrete material for rigid pavements to retain their friction property.
  Authors: Gonzalez, Marcelo; Safiuddin, Md.; Tighe, Susan Louise
  Authors: Gonzalez, Marcelo; Safiuddin, Md.; Tighe, Susan Louise
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 711
  Paper Number: 13-2248
• Local Calibration of MEPDG Distress Models for Flexible Pavements Using Ontario’s Long-Term PMS Data
  Abstract: Local calibration is an important step before a transportation agency adopts the AASHTO mechanistic-empirical pavement design guide (MEPDG). This paper presents the challenges of and findings from the local calibration of flexible pavements in provincial highways under the jurisdiction of the Ministry of Transportation of Ontario (MTO). A calibration database was developed that involved a hierarchical framework of the input parameters required for DARWin-ME (the MEPDG software) and the historical field performance data based on the MTO’s second-generation pavement management system (PMS-2). A calibration-clustering-validation approach was taken for the local calibration. The analysis suggested that whereas the MEPDG provided fairly unbiased prediction of the IRI value, it often over predicted the total rutting. A further clustering analysis based on functional class and geographical zone for the rutting and IRI, respectively, improved the precision of the locally calibrated models.
  Authors: Yuan, Xian-Xun; Jannat, Gulfam; Shehata, Medhat
  Authors: Yuan, Xian-Xun; Jannat, Gulfam; Shehata, Medhat
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 318
  Paper Number: 13-2303
• Development of a Guide for Replacement of Roadway Lighting with New Lighting Technologies
  Abstract: The development of a simple guide for roadway lighting replacement approaches in New York State using new light source technologies to maintain visibility for safety, while reducing energy use, is described. Several roadway types were evaluated: parkways, residential streets and rural intersections. A review of published literature and a survey of transportation engineers in New York State were conducted. Based on this information as well as data on new light source technologies, recommendations for roadway lighting system replacement were developed. Analyses of the visual efficacy produced by different lighting systems under nighttime conditions, and the performance characteristics of light emitting diode and induction fluorescent lighting systems, resulted in recommendations for replacement of high pressure sodium (HPS) lighting systems. Several new light sources that produce “whiter” light than the incumbent HPS technology used on most roadways have been developed and significantly improved in the past decade. In combination with recent information about driver and pedestrian vision under nighttime conditions, these sources could result in energy savings for different roadway types, ranging from about 7% to 50%. Energy savings for isolated rural intersections could depend upon the level of pedestrian traffic expected.
  Authors: Bullough, John D.
  Authors: Bullough, John D.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-2308
• Costs and Benefits of Price Adjustment Clause in FIDIC MDB
  Abstract: Project owners, bidders, and construction supervision engineers continue to grapple with questions on the price adjustment clause in the Conditions of Contract developed by the International Federation of Consulting Engineers for Multilateral Development Banks. The first question faced by a project owner is whether the adjustment provision should be retained, and if not, why? If retained, the questions that ensue have to be dealt with by both the project owner and the bidders. These are about the adjustment terms and conditions—start date, base date, thresholds, and the adjustment formula parameters such as cost elements, indices, and weightings. Although answers to these questions are available from different sources and been legislated in some countries, clear, empirical evidence of the benefits of providing for adjustment—increased competition, lower bid prices, market stability, and less risk of contractors defaulting—is lacking. Also, the effect of changing default adjustment parameters is largely unknown. This paper first examines literature and experts’ views on the above questions in relation to Asian Development Bank financed road construction contracts in Central Asia and the Caucuses. Then, Monte Carlo simulation is used to evaluate alternative answers to the questions. Simulation results show that project owners and bidders can both benefit from the adjustment provision. Bidders can increase their competitiveness by not adding an inflation risk premium while the owner can expect more realistic bid prices and benefit from price drops during construction unlike in fixed price contracts. However, neither party will gain from changing the default parameters, which increases uncertainty and cause bidders to add risk premiums.
  Authors: Seneviratne, Prianka Nalin
  Authors: Seneviratne, Prianka Nalin
  Year: 2013
  Document Type: Paper
  Subject: Construction; Design
  Session: 244
  Paper Number: 13-2312
• Field Performance of Cost-Efficient Cast-in-Place and Precast Prestressed Bridge Approach Slabs
  Abstract: Concrete bridge approach slabs (BAS) are used at the interface between bridge abutments and pavements that rest on compacted embankment. Three solutions were presented in a previous study for the Missouri Department of Transportation, including two cast in place (CIP) designs for new construction and a novel precast prestressed slab (PCPS) designs for new construction and replacement of BASs. These solutions were estimated to have a lower cost of the designs, and an equal or better performance compared to the current MoDOT designs. Currently a new study has been initiated where the recommended BAS designs are being implemented in the field. The main purpose of the project is to study the field performance, costs and construction issues of these solutions. The primary objectives of the proposed project are to a.) Examine the construction issues and actual costs of construction and b.) perform a long term field monitoring of a PCPS slab and field testing of the proposed designs. The research presented in this paper addresses all the three aspects of the study. This paper presents results from field monitoring of the PCPS BAS using strain and moisture gages, field load testing of both PCPS and CIP slabs and compares costs of construction with projected values. Based on the observations thus far the BASs constructed are performing very well and have met or reduced costs of construction.
  Authors: Thiagarajan, Ganesh; Nalagotla, Jitesh; Muncy, Nathan P; Myers, John J.; Halmen, Ceki
  Authors: Thiagarajan, Ganesh; Nalagotla, Jitesh; Muncy, Nathan P; Myers, John J.; Halmen, Ceki
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 628
  Paper Number: 13-1998
• Instrumentation and Long Term Monitoring of Three Integral Abutment Bridges in Vermont
  Abstract: The Vermont Agency of Transportation has initiated a program of field instrumentation and analysis to evaluate the performance of three Integral Abutment Bridges. The research components are being conducted by the University of Massachusetts at Amherst. Three bridges are studied, a straight girder non-skewed bridge with 43.0 m (141.0 ft) span, a straight girder 15 degree skewed bridge with 37.0 m (121.4 ft) span, and a curved girder non-skewed two-span continuous structure with 11.25 degrees of curvature and 68.0 m (221.8 ft) total bridge length. The bridges instrumentation includes strain gages, pressure cells, crack meters, inclinometers, tilt meters and thermistors to monitor long term response to seasonal thermal load. This paper describes the bridge details and instrumentation at these sites and reports on the overall bridge movements and pile moments through the first year of data. The bridges with moderate skew of 15 degrees and curvature of 11.25 degrees exhibited longitudinal abutment deformations similar to what would be expected in a straight girder non-skewed structure. The transverse abutment displacements of these bridges were less than 4 mm (0.15 in.). However, pile restraint of transverse abutment displacements resulted in strong axis pile moments exceeding those about the weak axis. Therefore, for these bridges a two-dimensional analysis captures global deformations, but design would need to account for bi-axial bending in piles.
  Authors: Civjan, Scott Adam; Kalayci, Emre; Brena, Sergio; Allen, Chad
  Authors: Civjan, Scott Adam; Kalayci, Emre; Brena, Sergio; Allen, Chad
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 525
  Paper Number: 13-2066
• Safety Impacts of Increasing Lengths of Left-Turn Lanes
  Abstract: Left-turn lanes can improve the safety and operation of intersections by providing space for deceleration and storage of turning vehicles. The length of the lane is critical in the design of left-turn lanes. Insufficient length may result in left-turn lane overflow which seriously impacts the safety of the intersection. The objective of this research is to determine the safety impacts of increasing storage lengths of the left-turn lanes. To achieve the objective of this research, field study was conducted at the intersections with different geometric, signal timing, and traffic flow conditions. Two approaches were employed to determine the safety benefits of increased storage lengths of left-turn lanes: 1) accident data analysis, and 2) simulation-based safety analysis. The research concludes that extending the length of left-turn lane to eliminate the left-turn lane overflow problem can significantly reduce the risk of rear-end accidents.
  Authors: Qi, Yi; Azimi, Mehdi; Yu, Lei
  Authors: Qi, Yi; Azimi, Mehdi; Yu, Lei
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 222
  Paper Number: 13-2097
• Effects of Asphalt Concrete Anisotropy on Predicted Pavement Response at High Temperatures
  Abstract: In this study, predictions of strain gauge calibrated full-scale micromechanical (MM) finite element (FE) models were used to identify the effects of asphalt concrete anisotropy on predicted asphalt concrete pavement performance. The accuracy of layered elastic theory (LET) models that are used in pavement design today were also evaluated. The MM FE model was first developed to simulate a laboratory shear test. Second, model parameters determined for the laboratory shear tests were used to develop MM FE models for full-scale pavement test sections. A virtual strain gauge was also included in the MM FE models for calibration. LET models were also calibrated using the measured strain gauge responses. Predictions of calibrated MM FE and LET models were compared to determine the effects of the absence of anisotropy in LET models on predicted pavement responses. Recommendations were also made for future use of the MM FE models to improve the predictive capability of LET models.
  Authors: Coleri, Erdem; Harvey, John
  Authors: Coleri, Erdem; Harvey, John
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 574
  Paper Number: 13-2166
• Falling Weight Deflectometer Loading Pulse Duration and Its Effect on Predicted Pavement Responses
  Abstract: Falling weight deflectometer (FWD) testing is commonly used to characterize, through backcalculation, in situ moduli of flexible pavement layers. While an often-used tool, it is well known that the short duration impact load applied by the FWD is often much faster than load durations applied by traffic. This can lead to an overestimation of asphalt concrete (AC) layer moduli under traffic which can underestimate computed pavement responses for design. The objective of this study was to determine the ability of FWD testing to represent traffic loading and pavement responses at typical operating speeds. FWD tests were performed on nine sections containing instrumentation at the National Center for Asphalt Technology (NCAT) Test Track. The measured FWD pulse durations ranged from 0.030 to 0.050 seconds over a range of temperatures. Measured loading pulse durations from trucks moving at 45 mph were found to be two to three times greater than the measured FWD pulse durations at the same temperature. The mechanistic analysis software 3D-Move was used to model moving loads to produce a loading pulse equivalent to the loading pulse produced by the FWD. The equivalent speed was determined to be over 120 mph. Statistically significant differences between the simulated responses from the Test Track operating speed of 45 mph and at simulated responses from the equivalent FWD speeds were obtained.
  Authors: Leiva-Villacorta, Fabricio; Timm, David H.
  Authors: Leiva-Villacorta, Fabricio; Timm, David H.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 665
  Paper Number: 13-2171
• Estimating Turning Movements at Roundabouts Using Bluetooth Technology
  Abstract: Turning movement counts at Roundabouts have historically been difficult to acquire. With the advent of Bluetooth wireless communication devices becoming commonplace for individuals to own and possesses while operating a vehicle, an opportunity was created to investigate the feasibility of applying this technology to turning movement counts at roundabouts. Two different locations were studied in Kansas, a rural five-leg, and an urban four leg roundabout were chosen. Bluetooth data loggers were deployed upstream of the central island at each location from which origin-to-destination leg data could be captured. When turning movement percentage data was compared to ground truthed human observations and statistically compared, the rural location was not statistically different, and the urban location barely was statistically different.
  Authors: Rescot, Robert Andrew; Schrock, Steven D.
  Authors: Rescot, Robert Andrew; Schrock, Steven D.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-2265
• Pavement Maintenance Management Through Network Partition
  Abstract: This paper presents a new optimization model to the problem of pavement maintenance planning for a large-scale road network. In the past, this problem has usually been formulated as linear programming or integer programming model. The solutions obtained from those models determine the timing, location and type of treatment to perform the maintenance operation for a given planning horizon. However, a shortcoming of those models is that the selected sections for maintenance are usually distributed spatially across the network, making it difficult to plan and implement maintenance activities in a coordinated manner. In light of the scale of economy, adjacent road sections with similar maintenance needs should be maintained within a single project. Unfortunately, the idea of automatically combining adjacent sections into one large project has not been given serious attention in existing optimization models for pavement maintenance planning. In this paper, a new solution approach to pavement maintenance planning is proposed that utilizes the spatial structure of the road network. The road network is first partitioned into groups of adjacent sections, or maintenance projects, with similar maintenance needs. Then, in order to maximize system performance a Knapsack problem is solved to optimally allocated resources to selected maintenance projects.
  Authors: Gao, Lu; Zhang, Zhanmin
  Authors: Gao, Lu; Zhang, Zhanmin
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 662
  Paper Number: 13-2296
• Evaluation of Large-Truck Crashes at Horizontal Curves on Two-Lane Rural Highways in Kansas
  Abstract: The objective of this study was to investigate the relationship between the roadway, environment, and resulting crash severity of truck crashes at horizontal curves located on rural two-lane state highways in Kansas. Single vehicle truck crashes and multi-vehicle crashes involving at least one truck crashes were extracted from the Kansas Department of Transportation’s crash and roadway databases for 2006 to 2010 which resulted in 452 crash records. Descriptive statistics and 95 percent confidence intervals were constructed for an odds ratio analysis comparing single-vehicle truck crashes to multi-vehicle crashes involving at least one truck for variables that were included in both databases.Overall, the odds ratio analysis indicated that single vehicle truck crashes were less likely to occur on wet pavement, with the shoulder rumble strips present, occurring during non-adverse weather conditions as compared to multi-vehicle crashes involving at least one truck. Single-vehicle truck crashes were also more likely to result in an injury crash as compared to multi-vehicle crashes involving at least one truck which were more likely to result in a fatality or property damage only crash.
  Authors: Fitzsimmons, Eric J.; Lindheimer, Tomas Ernesto; Schrock, Steven D.; Gonterwitz, Kyle
  Authors: Fitzsimmons, Eric J.; Lindheimer, Tomas Ernesto; Schrock, Steven D.; Gonterwitz, Kyle
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 571
  Paper Number: 13-2340
• Bridge Deck Scanning for Condition Assessment of Bare Concrete and Asphalt-Overlaid Decks
  Abstract: This paper presents technologies used for condition assessment of bare concrete decks and asphalt overlaid decks. The study was funded by the NCHRP-IDEA program. The objective of the research and development was to develop a faster, more accurate technology to determine internal conditions of bridge decks. A Bridge Deck Scanner (BDS) prototype with a pair of transducer wheels was originally developed. Later the BDS system was expanded as part of a SHRP 2 R06 (D) research project for asphalt pavement delamination (NCAT study at Auburn University) so that up to three pairs of transducer wheels could be added to the system for more rapid testing. The BDS system can be set to perform either Impact Echo Scanning on all wheels for condition assessment of bare concrete decks or simultaneously perform Impact Echo Scanning and Spectral Analysis of Surface Waves Scanning for condition assessment of concrete decks underneath overlays such as asphalt. In this paper, two case studies are presented (one from a bare concrete deck and one from an asphalt overlaid deck) in which comparison/ground-truthing techniques (sounding, coring, hydro-blasting, etc.) were employed along with BDS results.
  Authors: Tinkey, Yajai; Miller, Patrick K.; Leonard, Mark; Pott, Andy; Olson, Larry Duane
  Authors: Tinkey, Yajai; Miller, Patrick K.; Leonard, Mark; Pott, Andy; Olson, Larry Duane
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 500
  Paper Number: 13-2043
• Premature Cracking in Foamed Asphalt Pavement: Peru-Brazil Highway Case Study
  Abstract: The granular base stabilization with foamed bitumen is an alternative whose application is expanding by the increasing demand to preserve and minimize the use of virgin materials and reduce energy consumption. The purpose of this paper is to analyze the origin of premature cracks in the asphalt foaming of the road section I of Brazil Peru that began within hours of completion of the construction process and the evolution continued even when the surface treatment was placed. The scope of this work includes the evaluation and analysis of three critical components, the construction process, the mix design and structural capacity based on an extensive laboratory program and in situ evaluations. The total extension of the project is 470 miles, with foamed bitumen sections of 200 miles (the largest section of foamed bitumen built in South America) of which approximately 50 miles showed premature failure. The failures were mainly concentrated in areas with altitudes between 8,000 and 15,000 feet above sea level. Premature cracks were mainly due to a combination of poor curing process, low relative humidity, excessive fines content, and reduced structural capacity. It is recommended that similar projects should consider an early curing process, a quick surface seal, and adopt standards that consider at least a minimum required thickness, a tolerable range for fine contents, and a maximum allowable deflection.
  Authors: Menendez, Jose Rafael
  Authors: Menendez, Jose Rafael
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 555
  Paper Number: 13-2381
• Analysis of Knowledge of Crossing Rules, Self-Reported Behavior, and Observed Behavior at Intersections
  Abstract: Intersection crossing crashes are a serious problem for children in China and other countries. The objective of the study is to provide a better understanding of the relationships between children¡¯s intersection crossing knowledge and behavior to enable improvements to traffic safety education and to children¡¯s safety as they walk to and from school. We administered a Questionnaire to 225 primary school children aged 6-12 to assess their knowledge of crossing rules, self-reported crossing behavior, and we acquired 2 hours of Video recordings of children¡¯s observed crossing behavior from the same primary school as they crossed a busy intersection. We found there was large discrepancy between observed intersection behavior and knowledge of crossing rules according to gender and differed depending on whether they crossed with adults, with classmates or alone. Also significant differences existed between observed intersection behavior and the self-reported crossing behavior. One specific gender difference was that girls¡¯ behavior of looking both ways before crossing was better than boys¡¯. We also found that when children crossed intersections alone, their behavior was generally better than when they crossed with classmates or with adults in performing risky behaviors. While we found no significant differences between children¡¯s knowledge of crossing rules and their self-reported crossing behavior. A further observation was that when children were accompanied by adults, we observed the highest frequencies of crossing against the light. However, in spite of these gender differences in behavior, we found no significant gender differences with respect to knowledge of crossing rules. The weakness in the association between intersection crossing knowledge and behavior found in this study suggests that it is not enough to teach children knowledge that describes proper behavior for keeping safe in traffic. Children should also be directly taught the proper behaviors for keeping safe in traffic, preferably in the actual setting where they will be performed. Other countermeasures recommended include educating both children and adults on proper intersection crossing behavior, and emphasizing training for boys to improve their crossing skills. Some ways to implement these recommendations are considered in the discussion of this study¡¯s findings.
  Authors: Wang, Xuesong; Wang, Li; Tremont, Paul J.
  Authors: Wang, Xuesong; Wang, Li; Tremont, Paul J.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-2395
• Assessment of Pavement Cracking in Real Time Using Three-Dimensional Laser Technology and Advanced Image Analysis Algorithms
  Abstract: The analysis of pavement distress through cracking has provided major challenges for road authorities. Manual methods of analysis lack consistency due to the subjective nature of assessment and issues with image quality. Recent advances in image analysis and illumination have enabled automation of the data collection process, but have limitations in terms of data processing and classification. This paper compares two automated systems, RoadCrack and the Laser Crack Measurement System (LCMS), and recent advances in the integration of these technologies to provide real time cracking analysis.
  Authors: Warren, Garry
  Authors: Warren, Garry
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 475
  Paper Number: 13-2434
• Users’ Experience and Evaluation of New Southern Masha’er Metro Line in Makkah, Saudi Arabia
  Abstract: Each year during the 9th month of the Muslim lunar calendar, more than 2 million Muslim pilgrims from around the world travel to the Holy City of Makkah in Saudi Arabia to perform Pilgrimage. A significant milestone in the effort to improve the existing transport system in the Holy City has been the introduction of the Southern Masha’er Rail Line during the 2010 pilgrimage season. In its first year of operation, the line operated at only 35% of its full capacity, before full implementation in the following year when the line operated at full capacity of 72,000 passengers per hour. This paper presents the results of a users’ survey that aimed at assessing the performance of the rail line from the perspective of its users. The analysis revealed that the rail users faced longer access, waiting and egress times compared to regular rail operations standards. However, interestingly enough, the survey results show that the majority of pilgrims found these times to be tolerable. Moreover, the majority of users found the rail line and its stations to be of excellent quality and gave positive recommendations about using the rail line in the future. The analysis also produced some very interesting observations that may be of relevance to rail operation in similar crowded events; these are highlighted throughout the paper.
  Authors: Kaysi, Isam; Alshalalfah, Baha; Shalaby, Amer; Sayegh, Arwa; Sayour, Mounira; Gutub, Adnan
  Authors: Kaysi, Isam; Alshalalfah, Baha; Shalaby, Amer; Sayegh, Arwa; Sayour, Mounira; Gutub, Adnan
  Year: 2013
  Document Type: Paper
  Subject: Design; Passenger Transportation; Public Transportation; Terminals and Facilities
  Session: 389
  Paper Number: 13-2510
• Characterization of Crack Data from Continuously Reinforced Concrete Pavements on Lean Concrete Base
  Abstract: Extensive crack width and crack spacing data from recently constructed continuously reinforced concrete pavements (CRCP) on lean concrete base in China were collected and statistically analyzed in this study. A total of 29 CRCP sections were observed which lead to 1171 crack data. The cracks were classified into six different types according to their shapes and patterns. Kolmogorov-Smirnov test shows that CRCP crack spacing follows a four-parameter Dagum distribution. ANOVA tests show that slab thickness does not have a significant impact on crack spacing. However, it has a significant impact on crack width. Measured data show the crack spacing is not correlated to crack width. In addition, validation result shows that Mechanistic-Empirical Pavement Design Guide (MEPDG) crack spacing model significantly underestimates the field mean crack spacing.
  Authors: Zhang, Xiao; Zhao, Duijia
  Authors: Zhang, Xiao; Zhao, Duijia
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 474
  Paper Number: 13-2517
• Parametric Analysis of Corrugated Steel Plate Structures with Maximum Spans
  Abstract: Corrugated steel plate structures used for small bridges are commonly produced as single layer shell. When stiffness is not sufficient additional ribs are applied ( continuous or intermittent). Ribs are connected to the main barrel through bolts. For larger spans ribs can be filled with concrete giving so called EC ribs. The paper presents hybrid structure consisting of corrugated steel structure and pipes reinforced with concrete CFST (Concrete Filled Steel Tubular). This technology (CFST) is being currently used to construct arch bridges with large spans. Presented hybrid solution give comparable spans to newly developed solutions[5].
  Authors: Janusz, Leszek
  Authors: Janusz, Leszek
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Geotechnology
  Session: 216
  Paper Number: 13-2523
• Extended Validation of Finite Element Model for 2007 Chevrolet Silverado Pickup Truck
  Abstract: A finite element (FE) model based on a 2007 Chevrolet Silverado quad-cab pick-up truck was developed through the process of reverse engineering at the National Crash Analysis Center (NCAC) of The George Washington University (GWU). This detailed FE model was constructed to include full functional capabilities of the suspension and steering subsystems. This model was initially validated by comparing the simulation of the NCAP frontal wall impact with actual data from NHTSA tests for a comparable vehicle. This was supplemented with comparison to inertial and suspension response data that compared the vehicle before tear down to the FE model. Acceptable results of the initial validation led to the release of the FE model. Subsequently, interior elements were added to the model and additional validations were conducted. The first validation involved comparing data from other full frontal wall tests to the simulated test with the updated model. The model was also successfully validated against a side impact test. The robustness of the model was demonstrated by simulations of a centerline pole impact and damage consistency comparisons for rigid wall, offset deformable barrier, and centerline pole impacts at varying speeds. The simulations executed without error in these runs and the results reflected the expected responses and consistency with varying parameters. This led to the conclusion that the model was robust across various impact scenarios.
  Authors: Opiela, Kenneth Steven; Marzougui, Dhafer
  Authors: Opiela, Kenneth Steven; Marzougui, Dhafer
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 730
  Paper Number: 13-2565
• Extended Validation of Finite Element Model for 2010 Toyota Yaris Passenger Sedan
  Abstract: A finite element (FE) model based on a 2010 Toyota Yaris passenger sedan was developed through the process of reverse engineering at the National Crash Analysis Center (NCAC) of The George Washington University (GWU). The resulting FE vehicle model has 974,383 elements, without the interior components or restraint systems. This detailed FE model was constructed to include full functional capabilities of the suspension and steering subsystems. This model was validated by comparing the simulation of the NCAP frontal wall impact with actual data from NHTSA tests for comparable vehicles. Acceptable results of the initial validation led to the release of the FE model. Subsequently, validation efforts continued with comparisons to data from other full frontal wall and offset deformable barrier impacts. Simulation results compared well to data from these tests. Finally, model robustness was demonstrated by additional simulations of centerline pole impacts, full front and offset head-on collisions into a Chevrolet Silverado, and damage comparisons for impacts at varying speeds. The simulations executed without error in these runs and the results reflected the expected responses and consistency with varying parameters. This led to the conclusions that the model was robust across various impact scenarios.
  Authors: Opiela, Kenneth Steven; Marzougui, Dhafer
  Authors: Opiela, Kenneth Steven; Marzougui, Dhafer
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 730
  Paper Number: 13-2567
• Why Do We Tend to Drive Faster and Follow Vehicles Closer Than We Should in an Underground Road?
  Abstract: A driver maybe diminishes his sensitivity to speed gradually because of lack of variation in visual scenery in a long underground road and he tends to drive a vehicle faster and follow a vehicle closer than he should do unconsciously. This paper focuses on mechanism analysis of vehicle operating characteristics affected by visual environment in urban underground road based on information load. CONTENTS: 1) Comparing differences of vehicle velocity maintaining and headway estimating in different road environment; 2) Calculating driver visual information load level from diver¡¯s vision scene; 3) Mechanism analysis of driving behaviors affected by visual environment; 4) Taking technical measures to satisfy driver visual requirements in underground road environment. DATA: vehicle velocity, headway and diver¡¯s vision scene. METHODS: 1) Revealing differences of vehicle operating characteristics in different traffic environment with naturalistic driving; 2) Studying the influence mechanism based on theoretical calculation. 3) Proposing measures to improve urban underground traffic security on driving simulator.
  Authors: Chen, Yuren; Cai, Yang; Wang, Jie; Zeng, Xueke
  Authors: Chen, Yuren; Cai, Yang; Wang, Jie; Zeng, Xueke
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Safety and Human Factors
  Session: 208
  Paper Number: 13-2582
• Research on Dynamic Bending Behavior of Composite Beam Model for Asphalt Overlay on Steel Bridge Deck
  Abstract: A three-point composite beams model simulating asphalt overlay on orthotropic steel bridge deck was studied in this paper, which was designed for investigation of the dynamic bending behaviour of composite structure. Beam specimens were tested at three temperatures (5, 25, 45¡æ) and six frequencies (0.1, 0.5, 1, 5, 10, 20Hz) for the determination of the effect of temperature and frequency on the dynamic bending behaviour of composite beam. A Finite Element (FE) model was constructed to simulate the composite beam. The modulus of the asphalt overlay and the stiffness of the bonding layer were obtained by updating the material parameters in the FE model to fit the experimental results.The test results show that the dynamic deflection of composite beam increases with increasing temperature, but decreases with increase in frequency. The strains distribution in the epoxy asphalt overlay is almost linear but the shearing deformation of the bonding layer exists. With increasing modulus of the overlay and stiffness of the bonding layer, dynamic deflection of composite beam significantly reduced. The results also show that calculated strain distribution agrees fairly well with the results obtained from the dynamic bending tests on the composite beam.
  Authors: Yao, Bo
  Authors: Yao, Bo
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Safety and Human Factors
  Session: 703
  Paper Number: 13-2595
• Effect of Moisture Content on Pavement Behavior in a Heavy-Vehicle Simulator Test
  Abstract: A flexible test road structure was built and tested in an Accelerated Pavement Test (APT) using a Heavy Vehicle Simulator (HVS), to investigate its performance behaviour for a validation in a mechanistic performance scheme. In the test more than one million load cycles were applied, but approximately half way through the test, water was introduced to the pavement structure. The structure was therefore analysed in “moist” and “wet” state, before and after raising the water level. The increased water level had a significant effect on the responses of the structure with decreased resilient modulus and increased rate of accumulation of permanent deformation. Numerical analyses have been carried out to simulate the pavement responses, with the material properties based on field and laboratory testing. The observed accumulation of permanent deformation of the unbound layers was modelled using work hardening material models based on the numerical analyses. Generally good agreement was established between the measurements and calculations.
  Authors: Saevarsdottir, Thorbjorg; Erlingsson, Sigurdur
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 737
  Paper Number: 13-1191
• Development and Field Evaluation of a Texture Measurement System Based on Continuous Profiles from a 3D Scanning System
  Abstract: Pavement texture is a very important indicator of road serviceability. Pavement texture can be linked to the pavement skid resistance and traffic safety to the traveling public. Due to these important links, most transportation agencies across the nation require texture data for their Pavement Management System. Current pavement texture measurement methods use a high speed distance sensor or a 3D line scan device, both of which experience limitations on data stability. Problems caused by vehicle vibration, bad data from optical sensors and most importantly, speed dependency related to the sensor sampling and exposure time make the texture results either unreliable or inaccurate due to severe errors. This paper reports a study on the influence of speed on network level texture data collection and the development of a high speed and high precision 3D texture system. The experiment confirmed that improper selection of a sensor with a large exposure time will suffer significant speed dependency on measured texture data. The system developed in this study adopted a very small exposure time for each sampling and can produce accurate texture data largely independent from vehicle speed.
  Authors: Huang, Yaxiong; Copenhaver, Todd; Hempel, Phillip; Mikhail, Magdy
  Authors: Huang, Yaxiong; Copenhaver, Todd; Hempel, Phillip; Mikhail, Magdy
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 241
  Paper Number: 13-2615
• Development Guidance for Minimum Sign Area for Slipbase Supports
  Abstract: This study seeks to establish a minimum sign area to be mounted on a slipbase system to reduce severity of the roof crush and improve safety according to the new safety-performance evaluation guidelines included in MASH. Computer simulation was used to help predict whether or not secondary contact between a support system and an impacting vehicle would occur, and the probable location of the contact. Full-scale crash testing MASH 3-61 (1100C passenger car) and 3-62 (2270P pickup truck) were conducted with the vehicles impacting the sign support at a speed of 62 mph. A 12 ft2 sign size was mounted on a BWG 10 T-bracket configuration #2 pipe support type. Test 3-61 resulted in a roof crush of 4.75 inches, which did not meet MASH criteria. After carefully reviewing and interpreting a new set of computer simulation results, researchers suggested 14 ft2 to be the minimum sign size for a slipbase support system. A new full scale crash test MASH 3-61 (1100C passenger car) was performed on a 14 ft2 sign area. The new test met the MASH criteria. It is recommended that signs with an area between 14 and 24 ft2 would be mounted on a BWG 10 pipe support with slipbase. All signs with an area smaller than 14 ft2 need to be mounted on a 13 BWG pole with a wedge and socket system. Sign areas between 24 and 36 ft2 should be mounted on a schedule 80 pipe support with a slipbase support system.
  Authors: Silvestri, Chiara; Arrington, Dusty; Bligh, Roger P.
  Authors: Silvestri, Chiara; Arrington, Dusty; Bligh, Roger P.
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 730
  Paper Number: 13-2620
• Selection of Design Parameters for Construction of a Surrogate Model for the MEPDG
  Abstract: The American Association of State Highway and Transportation Officials’ (AASHTO) Mechanistic-Empirical Pavement Design Guide (MEPDG) is the most widely utilized M-E design procedure in the U.S. The MEPDG incorporates extensive climatic and empirical performance data. Inclusion of such extensive data hinders the computational efficiency of design with the MEPDG and likely includes design parameters of little significance to pavement performance. Construction of a surrogate model that emulates the behavior of the MEPDG can be utilized to reduce computational expense and is valuable in any situation where large numbers of evaluations are required. Development of a surrogate improves efficiency, but requires selection of a reduced quantity of design parameters compared to the MEPDG model that it is meant to emulate. This paper includes investigation of the required quantity of input parameters necessary to accurately imitate the MEPDG design procedure. This investigation will provide a tool for sensitivity analysis for the MEPDG. The objective of this paper is to develop a variable selection process for sensitivity analysis and construction of a surrogate model for the Level 1 MEPDG design procedure utilizing the DARWin-ME design software. Investigation of the importance of input variables is investigated for 3 distinct climate regions to examine the impact of climatic data on the relative significance of input variables. Sensitivity analysis will provide insight to the most significant design information for Level 1 analyses. Further, construction and verification of a surrogate model for a Level 1 MEPDG analysis incorporating the information obtained from the selection process is presented.
  Authors: Retherford, Jennifer Q; McDonald, Mark
  Authors: Retherford, Jennifer Q; McDonald, Mark
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 239
  Paper Number: 13-2623
• Development of an Asphalt Pavement Distress Evaluation Method forFreeways in China
  Abstract: Reasonable evaluation of the asphalt pavement distresses condition is a very important part of the pavement management system. The objective of this research is to develop an effective method to evaluate asphalt pavement distress condition in China. Three single evaluation indexes were proposed, namely the Transverse Cracking Evaluation Index (TCEI), Pavement Patching Condition Index (PPCI), and Pavement Surface Distress Condition Index (PSCI), to assessthe critical properties of asphalt pavement distresses. The pavement distress condition index (PDCI) was then developed as a general evaluation index by using the analytic hierarchy process (AHP). The feasibility of this evaluating method was validated using the field distress data collected from Ning Hang freeway and Fen Guan freeway in Jiangsu Province, China. The results showed that the PDCI can reasonably represent the distress condition in asphalt pavements. The index value can be well correlated with the actual condition of the in-place pavement. Therefore, a scientific and rational method has been established to evaluate Chinese asphalt pavement distress condition.
  Authors: Zhou, Lan; Ni, Fujian; Leng, Zhen
  Authors: Zhou, Lan; Ni, Fujian; Leng, Zhen
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 241
  Paper Number: 13-2600
• Case Study for Evaluating Benefits of Pavement Research: Final Results
  Abstract: The purpose of this paper is to describe a retrospective evaluation of heavy duty pavement innovations that were developed through research for a major rehabilitation project in California. The paper examines the performance benefits of the innovations and analyses the economic benefits of the research that resulted from the implementation of innovative pavement designs innovations. Performance benefits are presented through a brief description of the rehabilitation project, background on development of a long Life Pavement Rehabilitation innovation, and design requirements that limited permanent deformation (rutting) within the first five years of service. Results from field measurements confirm the innovative pavements met this performance criterion. Economic benefits of the research which resulted from the development and implementation of the innovative pavements are presented. The paper is a follow-up publication on the subject and contains the latest and final results on the pilot study to quantify direct benefits stemming from APT testing. It incorporates cost-benefit analysis including agency with- and without road-user costs and study the influence of the discount rate in net present value calculations. As expected, road-user costs have a significant influence on the cost-benefit calculations especially in the case of a heavily congested freeway. Results from the cost-benefit analysis show positive cost savings and benefit-cost ratios. Results reported in this paper show clear performance benefits from the innovations, indicate positive economic benefits from the research that led to innovations.
  Authors: du Plessis, Louw; Nokes, William; Burmas, Nicholas; Holland, T. Joseph; Harvey, John
  Authors: du Plessis, Louw; Nokes, William; Burmas, Nicholas; Holland, T. Joseph; Harvey, John
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 737
  Paper Number: 13-2604
• A Methodology to Estimate Bicyclists’ Acceleration and Speed Distributions at Signalized Intersections
  Abstract: As cities across North America install new infrastructure to accommodate a growing number and variety of bicyclists, installation of bicycle-specific traffic signals is a common design element. A recent survey has shown that there is there is a lack of consistency in their design and timing. In particular, minimum green signal timing is highly dependent on the assumed acceleration and speed performance of bicyclists’ but there is no detailed methodology to estimate these performance values. However, recent AASHTO, Caltrans, and NACTO documents require that an adequate clearance interval shall be provided and that in determining this minimum interval field investigation of bicyclists’ speeds is recommended. Furthermore, even if detailed video trajectories are available, the determination of a value for field speed and acceleration is not trivial because values of speeds and accelerations are a function of time and individual bicyclist performance. The purpose of this research is to develop and apply a general methodology to estimate bicyclists’ acceleration and speed for traffic signal timing applications. Utilizing physical equations of motion, this research analytically derives expressions that can be used to classify individual bicyclist’s performance as function of the observed acceleration profile. The analysis indicates that four basic acceleration profiles are possible and the profiles can be obtained using a parsimonious field data collection method. The methodology is successfully applied to two intersections in Portland, Oregon. A detailed statistical analysis of the results shows that the results are intuitive and that the methodology successfully categorizes bicyclists’ performance variations due to topography or demographic characteristics.
  Authors: Figliozzi, Miguel; Wheeler, Nikki; Monsere, Christopher M.
  Authors: Figliozzi, Miguel; Wheeler, Nikki; Monsere, Christopher M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-2697
• Behavior of a Typical Steel Bridge Superstructure Subjected to a Lateral Point Load on the Girder
  Abstract: The object of this paper is to present the results of the static nonlinear analysis of a typical composite I-girder bridge superstructure subjected to a concentrated lateral load at the girder level. The results of the analysis have demonstrated that the response of the bridge to such loads is essentially a local phenomenon rather than a system mechanism in the sense that damage remains concentrated within a limited portion of the loaded beam. It is only when the load is applied at the diaphragm or very close to it that the load is essentially transmitted to all the girders of the bridge. Otherwise, neither the number of girders, girder spacing, nor the distance between the diaphragms have any measurable effect on improving the capacity of the system compared to the capacity of the loaded beam. In that sense, there are no redundancy contributions to such a loading scenario.
  Authors: Fiorillo, Graziano; Ghosn, Michel
  Authors: Fiorillo, Graziano; Ghosn, Michel
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 317
  Paper Number: 13-2712
• Use of Precipitation Records in Drainage Design of Porous Asphalt Surface Layer
  Abstract: Precipitation, including rain and snow, in general has a negative effect on road system efficiency and safety. Porous asphalt (PA) layer, with its high permeability and its capacity to drain water from the surface, can largely mitigate this impact. The performance of PA surface layer should meet drainage requirements that depend on the local weather type and design targets of safety/efficiency levels. This paper proposed a method for incorporating local weather records into PA layer design. As hydrologic constructions are based on intensity duration frequency (IDF) curves, this paper discusses the use of the same method for designing PA layers. As the exposure time of pavement to wet weather may be more directly related to road accidents and efficiency, the method of wet exposure is introduced as well. An IDF versus wet exposure plot shows these two parameters are not correlated; thus the two parameters cannot be used interchangeably.The IDF curves were developed based on extreme weather experienced across a number of years. However, no evidence shows the extreme weather is the prevalent concern of pavement design. The design based on IDF criteria leads to a low invest/outcome ratio. For pavement, the total time of exposure to adverse precipitation appears to be more important. The wet exposure method can be improved to provide exposure times for the different designs and fulfill PA thickness design requirements based on local weather and safety/efficiency expectation.
  Authors: Tang, Lijie; Flintsch, Gerardo W.
  Authors: Tang, Lijie; Flintsch, Gerardo W.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 239
  Paper Number: 13-2720
• Three-Dimensional Finite Element Modeling of Instrumented Airport Runway Pavement Responses
  Abstract: The objective of this paper is to analyze runway pavement responses under moving aircraft tire loading using a developed three-dimensional (3-D) finite element (FE) model. The instrumented runway at Cagliari-Elmas airport (Sardegna, Italy) was modeled in the analysis, which consists of a 350-mm asphalt layer, a 400-mm granular base layer, and subgrade. The FE model characterized the asphalt layer as a linear viscoelastic material, and two interface bonding conditions between asphalt layers (full bonding and partial debonding) were used in the analysis. The aircraft tire loading was simulated using a nontraditional loading assumption that represents the non-uniform distribution of tire contact stresses along contact length and width under five ribs of an aircraft tire. Analysis results show that traditional loading assumption that assumes uniform contact stresses at the tire-pavement interface underestimates the critical tensile and shear strains in the asphalt layer. In particular, the relatively high contact stresses at tire edge ribs under heavy aircraft loading cause significant shear stresses at the pavement near-surface. The pavement responses under various loading conditions (aircraft type, wheel load, and speed) were calculated, and the critical responses were identified. Good agreements were achieved when the calculated pavement responses (vertical pressure and horizontal strain) at various locations were compared to the measured responses from field instrumentation. The model results show that partial debonding between asphalt layers causes much greater tensile strains at the bottom of the whole asphalt layer.
  Authors: Wang, Hao; Al-Qadi, Imad L.; Portas, Silvia; Coni, Mauro
  Authors: Wang, Hao; Al-Qadi, Imad L.; Portas, Silvia; Coni, Mauro
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 737
  Paper Number: 13-2732
• Study on Confirmation by Pedestrians of Approaching Right- or Left-Turning Vehicle While Crossing at Crosswalk
  Abstract: In this study head-turning behavior is analyzed to understand where is the best location for the pedestrian to confirm the approaching vehicle in crossing the crosswalk. From the result of the head-turning frequency, it is found that head-turning frequency is increasing towards the entry of the crosswalk and the conflict point. Moreover, results by the analysis of different attributes, head-turning frequency at nighttime or of the elderly person tends to be low; and head-turning was performed more at the conflict point. These results might show that there is a need to provide the information about approaching vehicle. In the pattern that vehicle approaches behind the research participants, head-turning frequency is low; and this imply the need of information for the pedestrians. By the result of the comparison with the different experiment settings, it is found that the position where pedestrian just enter the crosswalk is the best location to confirm the approaching vehicle in the 3 kinds of cases, such as elderly person (having difficulty in crossing), nighttime (restricted visibility), wearing headphones (restricted hearing sense). Moreover, many head-turning behavior were performed at the middle of crosswalk in the case that start position of research participant is R and right-turning vehicle is approaching, and this could be an appropriate confirming action. From the result described above, there exist many critical locations for the crossing pedestrian to confirm the approaching vehicle in a safe manner.
  Authors: Hamaoka, Hidekatsu; Hagiwara, Toru; Tada, Masahiro; Munehiro, Kazunori; Haga, Kentaro
  Authors: Hamaoka, Hidekatsu; Hagiwara, Toru; Tada, Masahiro; Munehiro, Kazunori; Haga, Kentaro
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-2793
• Assessment of Effects of Pier Configurations on Flow Pattern and Scour: Computational Fluid Dynamics Modeling Approach
  Abstract: Flow past piers with different configurations are modeled using three dimensional Computational Fluid Dynamics (CFD) method. The effects induced by different cross-sectional shapes (circular, square, diamond and lenticular), different aspect ratios and different attack angles are studied. The flow patterns including the horseshoe vortex, wake vortex and the vertical flow in front of the pier are analyzed for each configuration; the maximum values of bed shear stress and its overall distribution patterns around the piers with different configurations are also focused on for analysis. It is founded that pier shapes affect the flow pattern bed shear stress distribution pattern dramatically; aspect ratio does not affect the maximum shear stress and the overall pattern of the shear stress whereas it does influence the interaction between the vortex structures; the effect of attack angle is obvious and the degree of such influence also depends on the aspect ratio. An expression based on the concept of effective width is proposed to evaluate the combination effect of the aspect ratio and the attack angle on the maximum shear stress. The findings in this project are also related to the scour patterns around piers to gain some insights into the scour mechanism; possible applications of the CFD approach into practical engineering areas are also discussed, such as in initial scour rate estimation for bridge risk analysis and design guidance for bridge scour countermeasures and monitoring plans.
  Authors: Tao, Junliang; Gao, Quan; Yu, Xiong
  Authors: Tao, Junliang; Gao, Quan; Yu, Xiong
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Hydraulics and Hydrology; Pavements
  Session: 728
  Paper Number: 13-2840
• Framework for Numerical Simulation of Bridge Scour Focusing on Improvements of Sediment Transport Models
  Abstract: Bridge scour is a complicated process involving the interactions between flow and bridge piers and between flow and bed sediment. The existing numerical studies often coupled different sediment transport models to a turbulence flow model to simulate the scour process. The influence of the turbulence fluctuation and the lift force are not incorporated in the traditional sediment models. In this paper, we proposed a framework to evaluate the performances of different sediment transport models. Specifically, the sediment transport equations are given an in-depth study and a new modification method to the sediment models to include the above mentioned influences was proposed based on a comprehensive review. In this framework, the flow domain will be solved using a URANS approach with a k-? turbulence closure model; the sediment transport models (traditional and modified) will be coupled with the flow domain using the arbitrary Lagrangian-Eulerian method.
  Authors: Tao, Junliang; Yu, Xiong
  Authors: Tao, Junliang; Yu, Xiong
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Hydraulics and Hydrology; Pavements
  Session: 728
  Paper Number: 13-2852
• Probabilistically Characterizing Uncertain Inputs in Life-Cycle Cost Analysis of Pavements
  Abstract: Life Cycle Cost Analysis (LCCA) is an important tool to evaluate the merits of alternative investments. Inevitably, inputs for an LCCA are subject to a high level of uncertainty both in the short-term and long-term. Under its current implementation in the field, however, LCCA inputs are treated as static, deterministic values. Conducting such an analysis, although computationally simpler, hides the underlying uncertainty of the inputs by only considering a few possible permutations, which could potentially lead a decision-maker to the incorrect pavement selection. One methodology that has gained traction the past decade is to describe uncertain parameters probabilistically, allowing the analysis to consider a range of possible outcomes. Although this methodology is recommended by the Federal Highway Administration (FHWA), practitioners still generally conduct deterministic LCCAs. One of the major reasons is that further research must be conducted to statistically characterize uncertainty for input parameters. This research attempts to build upon previous work by probabilistically characterizing several input parameters with and without readily available empirical data. Having characterized uncertainty and variability in the LCCA of pavements, the methodology presented is applied to a case study to determine whether the pavement selection would change by treating parameters probabilistically. The results of the analysis showed the pavement selection could change by conducting a probabilistic LCCA and are dependent upon the risk-perspective of the decision-maker.
  Authors: Swei, Omar; Gregory, Jeremy; Kirchain, Randolph
  Authors: Swei, Omar; Gregory, Jeremy; Kirchain, Randolph
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-2858
• Application of Computer Vision to the Diagnosis of Pedestrian Safety Issues
  Abstract: This paper demonstrates the potential of using computer vision techniques for solving several shortcomings associated with traditional road safety and behavior analysis. Surrogate data such as traffic conflicts provide invaluable information that can be used to better understand collision contributing factors and the collision failure mechanism. Recent advances in computer vision techniques encouraged the use of proactive safety surrogate measures such as conflicts and violations detections. The objective of this paper is to demonstrate the automated safety diagnosis of pedestrian crossing safety issues using computer vision techniques. The automated safety diagnosis is applied on a major signalized intersection in Downtown Vancouver, British Columbia. Concerns were raised regarding the high conflict rate between vehicles and pedestrians as well as an elevated number of traffic violations (i.e., jaywalking) at the intersection. This study is unique in its attempt to extract conflict indicators and detect violations from video sequences in a fully automated way. This line of research benefits safety experts as it provides a prompt and objective safety evaluation for intersections. It also provides a permanent database for traffic information that can be beneficial for a sound safety diagnosis as well as for developing safety countermeasures.
  Authors: Zaki, Mohamed H.; Sayed, Tarek; Tageldin, Ahmed; Hussein, Mohamed Hussein Azab
  Authors: Zaki, Mohamed H.; Sayed, Tarek; Tageldin, Ahmed; Hussein, Mohamed Hussein Azab
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-2889
• Evaluating Sustainability of Face Bricks for Road and Airfield Pavements
  Abstract: The U.S. Army Engineer Research and Development Center evaluated the feasibility of using face bricks as an alternative to concrete or asphalt paving for lightweight and heavyweight vehicle traffic. Paving materials and equipment can be scarce in expeditionary environments, so the use of bricks recycled from existing infrastructure may provide a local resource for constructing pavements suitable for meeting the military’s mission requirements. The field testing documented in this paper follows a laboratory study in which a series of tests, including compressive strength, absorption, Los Angeles abrasion, and specific gravity, were conducted on selected face bricks and brick pavers. The success of the laboratory testing led to the full-scale field testing and evaluation of the face and paver bricks trafficked with a commercial dump truck load of approximately 54,000 lb (24 494 kg) and then trafficked with a 45,000-lb (20 412-kg) single-wheel C-17 aircraft load cart. The field testing indicated brick-paved roads constructed with a moderately high-strength base are capable of sustaining more than 10,000 passes of truck traffic without failure. The same brick-paved roads were not capable of withstanding C-17 aircraft traffic. Further results from the evaluation are presented and include material characterization test data, rut depth measurements, wheel path and cross-section profile measurements, instrumentation response data, and forensic assessments. Recommendations for continuing the study through the use of additional full-scale test sections are also provided.
  Authors: Bell, Haley P.; Edwards, Lulu
  Authors: Bell, Haley P.; Edwards, Lulu
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Pavements
  Session: 705
  Paper Number: 13-2905
• Impact of Bicycle Boxes on Safety of Cyclists: Case Study in Montreal, Canada
  Abstract: This paper presents a methodology to evaluate the effectiveness of a bicycle treatment (bike boxes) at intersections using a before-after surrogate safety analysis based on longitudinal video-data analysis. As a surrogate safety measure, cyclists’ red-light violations are quantified for two periods before and two periods after the installation of a bicycle box at a signalized intersection in Montreal. For this purpose several hours of video were collected before and after the installation of the treatment. Based on the video data, red-light violations and potentially associated factors were collected for each cyclist that crossed the intersection, such as sex, age, group size, use of helmet, whether a cyclist stopped before crossing, vehicle-cyclist gap, etc. Violations with a short vehicle-cyclist gap were classified as dangerous (i.e., those situations in which cyclists pass the intersection during the red phase with a small vehicle gap). For the data analysis, a multinomial logit regression technique was used to identify the factors that increase or decrease the probability of cyclist violations as well as their changes over time. Both raw estimates and model estimates show that the presence of a bicycle box has a significant impact on the total number of cyclists’ violations; however, the impact on the number of dangerous violations is not clear. More video data from other intersections before and after the treatment implementation is required to validate these preliminary conclusions. Moreover, the video-data generation and surrogate approach proposed here can be applied to the evaluation of other bicycle treatments.
  Authors: Zangenehpour, Sohail; Miranda-Moreno, Luis Fernando; Saunier, Nicolas
  Authors: Zangenehpour, Sohail; Miranda-Moreno, Luis Fernando; Saunier, Nicolas
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-2909
• Comparison of LED Luminaires for Roadway Lighting Using Object Detection and Color Recognition Distances
  Abstract: This study compared two LED luminaires and their abilities to provide detection distance and color recognition distance of potential roadway hazards. Detection distance is regarded as a metric of visibility. Color recognition distance is a metric for comparing the impact of the CCT (Correlated Color Temperature) of each luminaire and their color contrast impact. Mesopic vision, the mode of vision most commonly used for night driving, was considered in this study. The impacts of luminance and color contrast were addressed in this study. The experiment was performed on the Virginia Smart Road where small wooden targets of different colors and pedestrians wearing different colors were detected by drivers of a moving vehicle in a controlled environment. The key difference between the two luminaires was their color temperatures (3500K versus 6000K). The results indicated that neither light source provided a significant benefit over the other although significant interactions were found among object color, age, and lighting level. The results indicate that the luminaires provide similar luminance contrast but their color contrasts depend heavily on the color temperature, the object, and the observer.
  Authors: Terry, Travis Neal; Gibbons, Ronald B.
  Authors: Terry, Travis Neal; Gibbons, Ronald B.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 550
  Paper Number: 13-2929
• Development of Roughness Models Using Alberta Transportation’s Pavement Management System
  Abstract: Alberta Transportation (AT) conducts annual automated roughness measurements on Alberta’s core highway network. The measures are used to classify the physical conditions of each pavement segment in the Pavement Management System (PMS) and to establish rehabilitation and preservation strategies for the year. Currently, no prediction model is available to correlate climatic, mechanistic and structural characteristics of the pavement to roughness development for Alberta’s network. Existing models incorporated in the Mechanistic Empirical Pavement Design Guide (MEPDG) and Highway Development and Management Tool (HDM) comprise comprehensive and detailed distress records. Such data record is not currently available for Alberta, so existing models cannot be calibrated for local conditions. The present study focuses on identifying significant variables to roughness development for Alberta’s highway network. In this study, the data available in the PMS is used to develop two new prediction models for the International Roughness Index (IRI): one for new, and the other for straight overlaid asphalt concrete (AC) sections with a granular base. Regression analysis conducted in the study revealed that variables such as age, traffic, percent fines in the subgrade, rut depth and cracking are most significant to IRI for the new AC sections with GBS, and that variables such as age, freezing index (FI), base and overlay thickness and rut depth are most significant to IRI for overlaid sections. The model for new AC sections was validated using data from the General Pavement Section (GPS)-1 in the Long Term Pavement Performance (LTPP) database located in the provinces of Alberta, Manitoba and Saskatchewan in Western Canada.
  Authors: Nassiri, Somayeh; Shafiee, Mohammad Hussein; Bayat, Alireza
  Authors: Nassiri, Somayeh; Shafiee, Mohammad Hussein; Bayat, Alireza
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-2897
• Operational Analysis of “Sharrows” on Roadways with Narrow Lane Widths
  Abstract: Sharrows are intended to encourage shared use of a facility for both bicycles and motor vehicles, as well as indentify the appropriate placement for bicyclists within the roadway. This paper analyzes the influence of several site characteristics on the operational and safety effects on bicyclists and motorists at two curbed roadway segments in Florida. Three main site variables were studied: lateral separation between vehicles and bicyclists, vehicle encroachments to the adjacent inside lane, and distance from face of curb that bicyclists track. Results suggest that installation of sharrows can increase the lateral vehicle clearance significantly. It was also observed that less restrictive lane changing conditions greatly increase the lateral separation between vehicles and bicyclists. Also, the percentage of vehicles that passed along side bicyclists with little to no encroachment was notably reduced after sharrows were placed, suggesting positive safety effects for bicyclists. Overall, operational effects for bicyclists and motor vehicles were positive with the implementation of sharrows.
  Authors: Sando, Thobias; Angel, Michelle; Hunter, William Wesley; Chimba, Deo; Kwigizile, Valerian
  Authors: Sando, Thobias; Angel, Michelle; Hunter, William Wesley; Chimba, Deo; Kwigizile, Valerian
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-2507
• Extracting 3d Transportation Features From Kinect Sensor Array Data
  Abstract: Three-dimensional modeling of transportation infrastructure assets such as roadways, bridges, signage, guard rails, etc., provide engineers an analysis framework that previously was too labor intensive and cost prohibitive to manually collect. The emerging industry standard for point cloud data collection is the use of either airborne or terrestrial based Light Detection and Ranging (LiDAR). The problem is that LiDAR hardware currently costs tens to hundreds of thousands of dollars and requires trained personnel to operate. Described within this paper are examples of how a low cost consumer grade electronic, the Microsoft Kinect sensor, can be used to collect point cloud data similar to terrestrial based LiDAR. For less than two hundred and fifty dollars, a Kinect sensor can be used by engineers to capture a wide range of transportation features such as bridge underpass heights, guard rail features, road signs, and the distance of the nearest roadside object. The approach presented herein automatically locates bridge under-passes with the Kinect Sensor, calculates the lowest clearance, and exports that data in an attributed GIS shapefile. In addition, guard rails and road signs can be identified and measured from Kinect sensor data.
  Authors: Hudnall, Matthew; Graettinger, Andrew J.
  Authors: Hudnall, Matthew; Graettinger, Andrew J.
  Year: 2013
  Document Type: Paper
  Subject: Construction; Data and Information Technology; Design
  Session: 729
  Paper Number: 13-2733
• Application of Impact Echo Scanning for Void Detection on Concrete Test Beams That Replicate Different Surface Finishes
  Abstract: The purpose of this study is to investigate the application of the hand-held impact echo scanning system for void detection in concrete structures. Three beams were designed to represent various surface and void conditions including different surface finishes (smooth, broom, and tined), overlays (rapid set, latex, and polymer), and rebar location. Impact echo (IE) testing was performed using the hand-held IE scanner system, which automatically performs an IE test every 1 in (25 mm). The scans were performed perpendicular to the direction of the foam voids. Comparisons of the defect interpretations and the actual design conditions of the beams are presented. It was concluded that while the hand-held IE scanner performed well in applications with relatively smooth surface, it has difficulty with applications with rough surfaces. The rough polymer, tined, and broomed surfaces caused poor quality data. However, the hand-held IE scanner was still able to detect shallow delaminations even from structures with rough surfaces. The scanner’s small size and weight make it ideal for testing smooth surfaces where testing is more difficult, such as vertical or overhead surfaces.
  Authors: Lewis, Kevin G.; Sharp, Stephen R.
  Authors: Lewis, Kevin G.; Sharp, Stephen R.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 500
  Paper Number: 13-2832
• Streicker Bridge in Its Early Years: Structural Identification and Damage Characterization
  Abstract: Streicker Bridge on the Princeton University Campus is a new pedestrian bridge completed in 2010. It is equipped with a Structural Health Monitoring (SHM) system aimed to transform the bridge into an on-site laboratory for research and educational purposes. Its very slender elements, modern materials and daring geometry create a structurally complex system. This on-site laboratory gives an opportunity not only to assess the structural behavior of this particular bridge but also to gain experience, research and develop sensing technologies, as well as to develop and validate data analysis techniques for damage detection and structural identification. Two fiber-optic sensing technologies are currently permanently deployed: discrete long-gage sensing based on Fiber Bragg-Gratings (FBG) and truly distributed sensing based on Brillouin Optical Time Domain Analysis (BOTDA). The sensors were embedded in the concrete deck during the construction. Several static and dynamic load tests were made and combined with major events such as the removal of the formwork to perform structural identification and damage characterization. An overview of the structural identification of the bridge performed at an early stage of its life is presented in this paper. It includes a description of the monitoring system, the applied monitoring strategies and in particular the global static behavior, characterization of a damaged joint, dynamic behavior and thermal effects. The results show that the selected monitoring strategy was suitable for monitoring this complex bridge, and that the selected monitoring system was able to capture the main features related to the real structural behaviors of the bridge.
  Authors: Sigurdardottir, Dorotea Hoeg; Glisic, Branko; Afonso, Jose Pedro Sousa
  Authors: Sigurdardottir, Dorotea Hoeg; Glisic, Branko; Afonso, Jose Pedro Sousa
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 500
  Paper Number: 13-2714
• Spectral Analysis of Surface Waves Scanning to Identify Debonding Conditions Between Hot-Mix Asphalt Layers in Pavements
  Abstract: This paper presents a recently developed system used for condition assessment of hot mix asphalt (HMA) pavements to detect debonding between layers of HMA pavements. The study was partly funded by the SHRP2 (R06D) research project titled “Nondestructive Testing to Identify Delaminations between HMA Layers” through the National Center for Asphalt Technologies (NCAT). The objective of the study was to develop a reliable technique to determine internal condition of HMA pavements including debonding conditions between each layer. An Impact Echo and Spectral Analysis of Surface Waves Scanner (IE/SASW Scanner) prototype (originally developed for condition assessment of bridge decks) with up to three pairs of transducer wheels using Spectral Analysis of Surface Waves scanning was employed in this project. This paper includes background of the development of the IE/SASW Scanner and a case study performed on HMA pavements of known conditions at the NCAT Pavement Test Track. The research investigation was performed as a “blind” study, with the actual known pavement conditions revealed to the research team after initial data analysis and reporting of detected delamination conditions was completed.
  Authors: Tinkey, Yajai; Miller, Patrick K.; Olson, Larry Duane; Heitzman, Michael
  Authors: Tinkey, Yajai; Miller, Patrick K.; Olson, Larry Duane; Heitzman, Michael
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 260
  Paper Number: 13-2990
• Nondestructive Evaluation-Based Assessment of Deterioration Progression in Concrete Bridge Decks
  Abstract: Within the framework of the Long Term Bridge Performance (LTBP) program, decks of several bridges throughout the United States are being periodically monitored using a variety of nondestructive evaluation (NDE) techniques. This paper discusses the monitoring of deterioration progression by NDE in two bridge decks in the states of Virginia and California over a two-year period, from 2009 to 2011. Given their importance to the state DOT's, three major deterioration types are considered: delamination, reinforcement corrosion, and concrete degradation. The NDE techniques used to detect and characterize the deteriorated areas of the deck include ground penetrating radar (GPR), impact echo (IE), ultrasonic surface waves (USW), half-cell potential (HCP), and electrical resistivity (ER). Deterioration maps for each bridge deck are presented and the damage progression over the two-year period is discussed for each individual deck. A condition rating scheme with respect to each deterioration type is introduced as a quantitative measure of the deck condition. The overall condition rating of a particular deck is calculated as the weighted average of individual condition ratings. Utilizing these condition ratings alongside segmentation of the deck can significantly improve the efficiency of deck rehabilitation prioritization. This study paves the way for developing more objective and realistic performance prediction models for reinforced concrete bridge decks, and for more objective assessment of the effectiveness of various approaches to deck rehabilitation.
  Authors: Gucunski, Nenad; Romero, Francisco A.; Imani, Arezoo; Fetrat, Farhad A.
  Authors: Gucunski, Nenad; Romero, Francisco A.; Imani, Arezoo; Fetrat, Farhad A.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 269
  Paper Number: 13-3043
• Failure Analysis and Retrofit Strategy of Cardenal Raúl Silva Henríquez Bridge During 2010 Earthquake in Chile
  Abstract: This paper presents a case study of the Cardinal Raúl Silva Henàiquez Bridge that experienced significant damage during the February 27, 2010, Chile Earthquake. Supported by reinforced concrete and steel columns with varying heights, the superstructure of the bridge consisted of 22 steel girder spans with one intermediate expansion joint located at the middle of the bridge. At each end of the bridge, the bottom flanges of the girders were welded onto their bearing steel plates that were embedded and anchored into the bridge abutment. Two three-dimensional finite element models (global versus local) with beam and solid elements, respectively, were established for bridge response and damage process simulations. Field observations indicated and finite element simulations verified that the damage was mainly caused by the excessive seismic load of 11 continuous steel-girder spans under longitudinal earthquake loading and its eccentricity from the girder-to-abutment connection, resulting in a significant bending effect. Parametric studies demonstrated that an effective retrofit strategy can be developed by reducing the number of continuous spans, modifying the girder-to-abutment connection detail, and increasing the capacity of girders with enlarged bearing seats, additional stiffeners for girders, and thicker flanges and webs.
  Authors: Wang, Zuocai; Chen, Genda; Yen, Wen-huei Phillip; Buckle, Ian G.
  Authors: Wang, Zuocai; Chen, Genda; Yen, Wen-huei Phillip; Buckle, Ian G.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 810
  Paper Number: 13-3048
• Laboratory Test of the Fire Protection Layer Used in the Soil-steel Tunnel in Poland
  Abstract: Flexible corrugated steel culverts have been used in engineering for many years, with the first application in 1931. Since that time, the popularity of these structures has increased enormously. Soil-steel bridges are more and more used as road and railway tunnels and heightened interest on the issue of structural fire protection of tunnels.In summer 2012 the tunnel built of the steel corrugated sheets were constructed in Karpacz city in Poland. The structure served as road tunnel under ski slope. A 100 m long tunnel is a metal open arch with a span of 11.15 m and a rise of 6.50 m. The steel tunnel with the fire protection is a first buried structure in Europe. This paper describes laboratory tests of protection layer during experimental fire tests. The main goal of conducted laboratory fire tests was to evaluate the steel structure with fire protection layer in configuration of part tunnel structure. Temperature on the surface of the steel plates and deflections in metal plates were measured. The instrumentations included temperature gauges installed on the metal plates and a device to monitor deflections of the structure. The experimental results obtained during measurements are shown in graphs/tables.The research project is sponsored by ViaCon Company and Torkret Company in Poland.
  Authors: Kunecki, Bartlomiej
  Authors: Kunecki, Bartlomiej
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: AFF60
  Paper Number: 13-3015
• Improvements of Full-Depth Repair Practices for CRCP Distresses
  Abstract: The Texas Department of Transportation (TxDOT) has by far the most continuously reinforced concrete pavement (CRCP) lane miles in the nation and sections as old as 50 years are still in service. Having served much longer than intended, some sections are showing distresses. FDR (full depth repair) is one of the methods to repair CRCP distresses in Texas. Over the years, various FDR methods have been used and the effectiveness of each method has varied. The most widely used FDR method – where full-depth cut is made at a minimum of1.5 ft (0.46 m) inside the transverse repair boundaries and partial-depth cut at repair boundaries, with the concrete in between removed to expose longitudinal steel – has inherent disadvantages, with longer repair time required being the primary disadvantage. Full-depth cut FDR method – where full-depth cut is made at repair boundaries with longitudinal tiebars epoxy grouted into the existing concrete – has advantages over other methods, one of which is the fast operations, minimizing the time of roadway closure. Since CRCP is normally utilized at high traffic volume areas, the maximum time allowed for the FDR operation in TxDOT is normally limited to nine hours, which makes the full-depth cut method the only acceptable repair method. Factors affecting the effectiveness of the full-depth cut method were investigated by laboratory testing and field evaluations. The way epoxy is injected, the ability to keep the epoxy in the holes after tiebars are inserted, restoring base support, and embedded length of tiebar were the most important variables affecting the performance of FDR. Based on the research findings, recommendations were made to revise specifications for FDR and epoxy materials, and it is expected that the implementation will result in improved FDR performance of CRCP.
  Authors: Ryu, Sung Woo; Choi, Pangil; Choi, Seongcheol; Won, Moon
  Authors: Ryu, Sung Woo; Choi, Pangil; Choi, Seongcheol; Won, Moon
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 441
  Paper Number: 13-3103
• Roadside Clearance Limit on Horizontal Curves with Transition Arcs:Sites with Circular Arcs Shorter than Sight Distance
  Abstract: The AASHTO guideline for geometric design of highways requires that insides of horizontal curves be cleared of obstacles to vision in order to provide required sight distance. However, the guideline does not have a method for determining the extent of roadside clearance for horizontal curves having transition arcs. Instead, the guideline recommends use of graphical and computational methods for the purpose. The graphical method is tedious and prone to errors. The computational method works only for sites with circular arcs equal to or longer than sight distance. This study has developed an analytical model for design clearance offsets for sites with circular arcs shorter than sight distance. Offsets were defined as normal ordinates from highway alignment to a curve that demarcates roadside area that accommodates sightlines. Variables in the model are sight distance, lengths of transition and circular curves, radius of circular curve, and driver location. Using the model, a design chart for maximum offsets and another for intermediate offsets were developed for use by practitioners. The maximum and intermediate design offsets for horizontal curves that have circular arcs that are shorter than sight distance were found to be significantly shorter than those for circular curves that are longer than sight distance. Use of the design offsets will avoid extra excavation costs that result from using bigger offsets determined by other models. Results of this study will be of value to engineers involved in design policies, highway maintenance as well as improvement designs for sites deficient in sight distance.
  Authors: Mauga, Timur; Ghanma, Mwafag; Ahmed, Kamran
  Authors: Mauga, Timur; Ghanma, Mwafag; Ahmed, Kamran
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 727
  Paper Number: 13-3113
• Analysis of Pavement Surface Distress Condition on Major Corridors in New Mexico
  Abstract: Road and highway networks, as a part of the transportation infrastructure, play an indispensable role in the local economy and community development. The high-quality pavement serviceability of these networks is essential to ensure safe, cost-effective, daily traffic operations. In-depth analyses of wide-range pavement surface condition data are necessary inputs for optimal pavement design and maintenance, traffic safety enhancement, and sustainable traffic infrastructure system development. This study aims to investigate various pavement condition performance measurements and their correlations, and better understand temporal-spatial characteristics of roadway surface distresses based on the pavement distress condition data collected by the New Mexico Department of Transportation (NMDOT) from 2006 to 2009. Eight major corridors across various urban and rural areas were selected for analyzing pavement surface distress conditions and discovering their intrinsic characteristics and patterns across both temporal and spatial domains in New Mexico. The analyses results show there are not significant correlations among different surface distress condition measurements at the significant level of p=0.05, implying the rationality of the current pavement condition performance measurements used by the state transportation agencies. The regression models were established and time series analyses were performed for extracting temporal and spatial patterns of distress rate (DR) data. The model results illustrate strong correlations of the DR data on the same route between two consecutive years, which can be partially characterized by a Markov chain process. GIS-based spatial investigations also show unique features of pavement condition deterioration attributed to diverse geometric characteristics and traffic conditions, such as vehicle compositions and volumes, etc. in urban and rural areas. The research findings are helpful to better understand the characteristics of pavement distress conditions and optimize traffic infrastructure design and maintenance.
  Authors: Chen, Cong; Zhang`, Su; Zhang, Guohui; Bogus, Susan; Valentin, Vanessa
  Authors: Chen, Cong; Zhang`, Su; Zhang, Guohui; Bogus, Susan; Valentin, Vanessa
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 241
  Paper Number: 13-3155
• Aerial Photograph-based Pavement Surface Distress Detection and Assessment
  Abstract: The New Mexico Department of Transportation (NMDOT) has used a manual, visual pavement distress evaluation method for many years. However, manual, visual evaluation of pavement surface distress is labor-intensive, time-consuming, and potentially dangerous. In order to overcome these limitations, this paper presents a novel approach for pavement surface distress detection through the use of aerial photos. This study was conducted using aerial photographs taken in 2010 and 2011 for part of the state of New Mexico. Twenty mileposts were selected as the study sites and the distress rates for these mileposts were calculated based on manual, visual observations using standard NMDOT protocols. Using the aerial photos as the base map, polygons were manually created on the aerial photos to simulate the visual evaluation zones. The statistics of the spectral response of different bands within these polygons were extracted and compared to the calculated distress rates using stepwise linear regression models. The results revealed that the spectral response in the aerial photos closely matches the calculated distress rates. These results open the way for the future use of aerial photographs to measure pavement distress rates, thereby providing a cost-effective, efficient, and safer alternative to traditional evaluation methods.
  Authors: Zhang`, Su; Bogus, Susan; Neville, Paul R.H.; Zhang, Guohui; Chen, Cong; Valentin, Vanessa
  Authors: Zhang`, Su; Bogus, Susan; Neville, Paul R.H.; Zhang, Guohui; Chen, Cong; Valentin, Vanessa
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 241
  Paper Number: 13-3156
• Crack Detection in Pavement Images Using Texture Analysis and Unsupervised Learning
  Abstract: The second phase of a two part study on using an unsupervised learning technique for the detection of road cracks from pavement images is described in this paper. The main concentration is on highly textured road images that make the crack detection very difficult. Road images are split into smaller rectangular cells and for each cells a representative data set is generated by analyzing image texture and colour properties. Texture and colour properties are combined with an unsupervised learning technique called the Kohonen map to distinguish crack areas from the background.Using this technique, cracks are detected to an accuracy of 75% was achieved. The background was segmented correctly with more than 99% accuracy despite it having very strong visual texture. The technique applied here shows a great deal of promise despite that the images were captured in an uncontrolled environment devoid of state-of-the-art image acquisition setups.
  Authors: Mathavan, Senthan; Rahman, Mujib; Kamal, Khurram
  Authors: Mathavan, Senthan; Rahman, Mujib; Kamal, Khurram
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 475
  Paper Number: 13-3174
• Methodology to Assess the Causes and Probability of Road Pavement Structural Failure
  Abstract: This paper presents a method to predict the probability of structural failure of road pavements using information contained in road datasets. Expert knowledge was used to develop failure charts which identify the potential factors that may contribute towards pavement failure. A computational technique, known as a Support Vector Machine, was built to use this information to determine from the datasets the probability of failure of individual road sections. With this prediction comes an indication of the predominant failure types, the causes of structural failure and the risk profile of a road network. The usefulness of the approach was demonstrated on a dataset taken from the New Zealand Long Term Pavement Performance study of State Highways, which predominantly consist of low-volume, flexible, unbound granular pavements. The analysis of the dataset showed that the network was in a good condition. It also identified a small number of pavement sections with a high likelihood of failure. Furthermore, the application of the failure paths examined the three predominant failure types occurring on the network and identified their possible causes. Rutting appears to be significantly influenced by the road pavement strength, cracking seems to be affected notably by the environment (i.e. water ingress) and shear failure is caused primarily by the combination of traffic, pavement composition and strength. In addition, it was confirmed that measured functional pavement condition alone is not a good identifier of failure, and that the inclusion of a parameter related to strength, such as pavement deflection, is essential.
  Authors: Schlotjes, Megan Rose; Burrow, Michael Peter Nicholas; Evdorides, Harry; Henning, Theuns F. P.
  Authors: Schlotjes, Megan Rose; Burrow, Michael Peter Nicholas; Evdorides, Harry; Henning, Theuns F. P.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 809
  Paper Number: 13-3175
• Toward Sustainable Pavement Management: Incorporating Environmental Impacts of Pavement Treatments into Performance-Based Optimization
  Abstract: Transportation asset management systems are concerned with the daunting task of maintenance and upgrade of infrastructures while restricted by annual budgets. However, the consideration of environmental impacts is normally left out of the analysis. This paper incorporates environmental impacts of maintenance and rehabilitation of pavements into the strategic planning. It explicitly considers greenhouse gas (GHG) emissions and energy usage from such activities and conducts a performance-based optimization. It follows a three-step tradeoff process: finding minimum requirement of annual budget, maximizing condition and reducing environmental impacts. The results show that considering environmental impacts in the strategic planning returns a substantial gain in energy savings and GHG emissions reduction although a small sacrifice in pavement performance is required. It reduces energy usage and GHG emissions by 19 percent and 24 percent, respectively, while pavement condition drops slightly to 98.5 percent of optimal solution.
  Authors: Faghih-Imani, Ahmadreza; Amador-Jimenez, Luis
  Authors: Faghih-Imani, Ahmadreza; Amador-Jimenez, Luis
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Pavements
  Session: 705
  Paper Number: 13-3154
• Lack-of-fit Analysis And Locked-in Forces Calculation-a Case Study Of A Curved Steel I-girder Bridge During Construction
  Abstract: Curved bridges generally exhibit critical attributes during construction, such as torsional deformations, diaphragm forces, and potential for uplift at bearings, which may induce fit-up difficulties. However, conventional analysis commonly employed in currently practice only addresses the internal forces associated with no-load fit (NLF) detailing without considering lack-of-fit effects. In this article, a method of lack-of-fit analysis was adopted to solve this problem and applied to a real case study. In this case study, the supports of a steel-concrete composite curved bridge were uplifted in the course of construction. A 3D finite element model was established by SAP2000 to simulate the erection procedures. Lack-of-fit analysis was conducted from total dead load fit (TDLF) detailing, in which locked-in forces in the structure were determined based on the diaphragm drops due to differential camber on and between girders. The results proved that the support uplift was temporary during erection and it was validated by bridge testing. It is concluded that this method of lack-of-fit analysis (3D-FEA method or even 2D-gird method) can simulate construction procedure, estimate lack-of-fit effects, and calculate locked-in forces from steel dead load fit (SDLF) detailing and total dead load fit (TDLF) detailing.
  Authors: Fu, Chung C.; Zhao, Gengwen; Xiang, Changsheng; Ahmed, Mohamed
  Authors: Fu, Chung C.; Zhao, Gengwen; Xiang, Changsheng; Ahmed, Mohamed
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: AFF20
  Paper Number: 13-3194
• Effect of Cross-Anisotropy of HMA Modulus on FWD Deflections and Embedded Sensor Stress-Strain
  Abstract: In this study, the effects of cross-anisotropy on asphalt pavement responses are examined. A dynamic Finite Element Model (FEM) is developed in ABAQUS to simulate pavement responses under Falling Weight Deflectometer (FWD) and truck loads on a pavement section at interstate I-40 (Mile Post 141) in New Mexico. This section has recently been instrumented with strain gauges, moisture probes, and pressure cells. Pavement response (i.e. stress, strain, deflection) from the instrumented section are compared to the FEM predicted values. Two combinations of cross-anisotropy are considered. First combination considers cross-anisotropy of modulus in every layers of the pavement, whereas the second combination considers it only in the Hot Mix Asphalt (HMA) layer. Time-deflection histories, stress, and strain are predicted from the FEM under FWD and truck loads. Results show that predicted deflections, stress, and strain are highly sensitive to cross-anisotropy. Predicted deflections, stress, and strain increase with a decrease in n-value, defined by the ratio of horizontal to vertical modulus of elasticity. Analyses are performed for two different shapes of loading area: semi-circle-rectangle and rectangle. It is shown that predicted stress and strain are larger for rectangular shape of loading area than for semi-circle-rectangle area. This study recommends including modulus anisotropy in FWD backcalculation and in pavement design.
  Authors: Ahmed, Mesbah Uddin; Tarefder, Rafiqul Alam; Islam, Md Rashadul
  Authors: Ahmed, Mesbah Uddin; Tarefder, Rafiqul Alam; Islam, Md Rashadul
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 665
  Paper Number: 13-3203
• Comparative Experimental Performance of Bridge Deck Slabs with AFRP and Steel Prestressed Precast Panels
  Abstract: Full-depth precast concrete panels expedite the construction process, enhance safety and quality control, and reduce the on-site labor requirements for bridge deck slab application. However, corrosion-induced deterioration of conventional steel during the lifetime of the structure is a serious concern affecting the durability and serviceability of the deck panels. Although replacing conventional steel with fiber reinforced polymer (FRP) bars has become more prevalent over the past few decades to overcome corrosion issues, there is still need for a comprehensive experimental study to investigate the structural performance of FRP concrete bridge deck slab with precast prestressed panels at full-scale and to address constructability issues as well. In this paper, a full-scale bridge deck slab consisting of full-depth precast panels reinforced and prestressed with aramid fiber reinforced polymer (AFRP) bars is experimentally investigated in terms of constructability and overall structural performance. Then it is compared to a similar system but reinforced with conventional steel and prestressing strand, deemed as the control specimen. The experimental results show the applicability of the proposed system having sufficient strength per AASHTO LRFD Bridge Design Specifications (2010) and considerable deformability when compared to the conventional system.
  Authors: Pirayeh Gar, Shobeir; Head, Monique Hite; Hurlebaus, Stefan; Mander, John
  Authors: Pirayeh Gar, Shobeir; Head, Monique Hite; Hurlebaus, Stefan; Mander, John
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Materials
  Session: 461
  Paper Number: 13-3207
• Measuring Unsafe Pedestrian Behavior Using Observational Data
  Abstract: Florida has a severe problem with pedestrian and bicyclist fatalities. Recent trends show that Florida’s pedestrian fatality rate is almost double the national average. Traditional safety programs rely on crash data to develop safety campaigns or countermeasures to increase safety. Since crash data are not readily available and a long time has to pass before meaningful data is collected, a “risk score” was developed to measure the behavior of road users at selected sites in Hillsborough and Miami-Dade counties. Surveys were conducted in June-July 2012 in two of the highest pedestrian crash and fatality counties in Florida to collect data and establish baseline conditions. The surveys included opinion surveys of pedestrians and observations of pedestrians and bicyclists, and their interaction with drivers. The locations where the surveys were conducted were selected based on site characteristics including pedestrian treatments or features, crash history, and land use. Thetwo surveys offered insight on the difference between what people know about the law or correct behavior, and what they actually do in reality. Results pinpoint the problems and aid in deciding the focus of safety campaigns and target audience. The risk score showed that the majority of sites exhibited unsafe behavior from pedestrians, bicyclists, and drivers. The risk score has the potential to aid in measuring the effectiveness of a safety campaign launched by FDOT focused on increasing the awareness on traffic laws. This way, appropriate countermeasures or funds can be selected for the higher ranking sites first.
  Authors: Kourtellis, Achilleas; Lin, Pei-Sung; Gawade, Makarand
  Authors: Kourtellis, Achilleas; Lin, Pei-Sung; Gawade, Makarand
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3208
• Monitoring of First “Bridge-in-a-Backpack” Bridge in Massachusetts
  Abstract: An innovative “Bridge-in-a-Backpack” bridge was constructed in Fitchburg, MA. The system, developed at the University of Maine, uses newly implemented technology of fiber reinforced polymer (FRP) tubes filled with concrete to reduce construction time and cost, reduce maintenance costs, and increase lifespan of the structure. The bridge is unique in that it has a 30 degree skew and shallower arch geometry than other bridges of this type that have been constructed. MassDOT, collaborating with the University of Massachusetts at Amherst, instrumented the bridge with a total of 99 gages (strain gages, pressure cells, tiltmeters, displacement transducers, and convergence gages). This paper discusses the bridge response under construction loads, static live load testing, and the first eleven months of long-term monitoring, to report on the observed performance of this innovative bridge.
  Authors: Quinn, Brooke Hollie; Civjan, Scott Adam; Lahovich, Andrew; Brena, Sergio
  Authors: Quinn, Brooke Hollie; Civjan, Scott Adam; Lahovich, Andrew; Brena, Sergio
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 426
  Paper Number: 13-3221
• Roughness Performance Model for Double Surface Treatment Highways
  Abstract: This paper presents the development of a roughness performance prediction model for double surface treatment highways. It is based on a factorial experiment design developed with data from the Department of Transport Infrastructure of the State of Bahia, Brazil, and also from data collected in 2009, when approximately 3,000 km of highways were travelled and 650 km of roughness survey were performed. The factors considered were pavement age, traffic volume and climate, the last one mainly in terms of rainfall. An Analysis of Variance (ANOVA) was performed to assess the significance of the factors and to define the parameters of the performance model. The obtained model was compared to other roughness prediction models and showed better correlation between observed and predicted values, indicating the validity of its use in pavement management analysis of double surface treatment road networks.
  Authors: Soncim, Sergio Pacifico; Fernandes, Jose Leomar
  Authors: Soncim, Sergio Pacifico; Fernandes, Jose Leomar
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-3191
• Investigation and Modification of Available Mechanistic-Empirical Procedures for Reflective Cracking in Asphalt Overlays of Concrete Pavements
  Abstract: Over the past decades, state, local, and federal use of asphalt concrete (AC) overlays to rehabilitate portland cement concrete (PCC) pavements has increased significantly. This situation has increased the attention given to mechanistic-empirical (M-E) modeling of reflective cracking. The paper describes recent research that assesses and modifies the state-of-the-art in mechanistic-empirical modeling of reflective cracking. This research reviewed the original Mechanistic-Empirical Pavement Design Guide (MEPDG) model and the CalME reflective cracking model. Furthermore, the paper details research that involved modification of the CalME model to facilitate its integration into the Mechanistic-Empirical Pavement Design Guide (MEPDG) for composite AC-over-PCC pavement projects.
  Authors: Khazanovich, Lev; Tompkins, Derek; Wu, Rongzong; Harvey, John
  Authors: Khazanovich, Lev; Tompkins, Derek; Wu, Rongzong; Harvey, John
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 579
  Paper Number: 13-3264
• Probabilistic Simulation of Cracking in Asphalt Pavements: Chilean Case
  Abstract: Deterioration models allow predicting pavement condition and the development of maintenance programs. Normally, when evaluating pavement performance through model deterioration, the forecast given is a determinist value. However, pavement engineering projects, as any engineering project, have a degree of uncertainty. This implies that an adequate performance of the engineering solution cannot be absolutely guaranteed.The aim of this research is to incorporate probability in the output of a structural cracking model. To achieve this objective the model of crack initiation and progression of HDM-4 was used under several scenarios defined based on geographic location, type of traffic and structural capacity of 86 roads located in Chile. The input data for each scenario were obtained from the Ministry of Public Works of Chile and calibration studies of deterioration models to local conditions. To incorporate probability in the structural cracking models, a simulation model that reproduced the deterioration due to cracking for a lifecycle of 25 years was developed, based on random input data sets. With the set of outputs of the simulation, probability density functions that represent the probabilistic response of the deterioration model were developed.The main output of this research is a set of probability density functions of cracking initiation and cracking progression of all structural cracks and wide cracks of 14 groups of Chilean roads. Although the research was carried out using Chilean data, the methodology presented could be applied to other states or countries.
  Authors: Rodríguez, Mario Alberto Moreno; Thenoux, Guillermo; Gonzalez, Alvaro Andres
  Authors: Rodríguez, Mario Alberto Moreno; Thenoux, Guillermo; Gonzalez, Alvaro Andres
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-3251
• Mechanistic-Empirical Pavement Design to Mitigate Rutting in Asphalt Overlays of Concrete Pavements Using MEPDG and CalME
  Abstract: This paper describes the development of an approach for the prediction of rutting of newly constructed composite pavements and asphalt overlays of existing concrete pavements (AC-PCC). It investigates the MEPDG rutting model and the CalME procedure being developed by Caltrans and the University of California Pavement Research Center (UCPRC) and introduces a procedure incorporating the CalME rutting model into the MEPDG framework. The overall goal was to provide a procedure for rutting in AC-PCC design and analysis for pavement engineers that does not require uncommon inputs and does not force the user outside of the MEPDG framework. The article also describes the validation of the developed procedure using experimental data from the UCPRC and from the Minnesota Road Research facility (MnROAD); in addition the article details a brief sensitivity analysis of the developed procedure for rutting in AC-PCC. It is hoped that the developed procedure represents a step forward for the design and analysis of AC-PCC using the MEPDG.
  Authors: Khazanovich, Lev; Tompkins, Derek; Saxena, Priyam; Wu, Rongzong; Harvey, John
  Authors: Khazanovich, Lev; Tompkins, Derek; Saxena, Priyam; Wu, Rongzong; Harvey, John
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 239
  Paper Number: 13-3258
• Service and Ultimate Limit State Flexural Behavior of One-Way Concrete Slabs Reinforced with Corrosion-Resistant Reinforcing Bars
  Abstract: This paper presents results of an experimental investigation to study the structural performance and deformability of a concrete bridge deck reinforced with corrosion resistant reinforcing (CRR) bars, i.e., bars that exhibit improved corrosion resistance when embedded in concrete as compared to traditional black steel. Flexural tests of one-way slabs were conducted to simulate negative transverse flexure over a bridge girder as assumed in the commonly employed strip design method. The bar types studied were Grade 60 (uncoated), epoxy-coated reinforcing (ECR, Grade 60), Enduramet 32 stainless steel, 2304 stainless steel, MMFX2, and glass fiber reinforced polymer (GFRP). The experimental program was designed to evaluate how a one-to-one replacement of the Grade 60 with CRR, a reduction of concrete top clear cover, and a reduction in rebar quantities in the bridge deck top mat influences flexural performance at service and ultimate limit states. The MMFX2 reinforced slabs exhibited the highest flexural strength because of the correspondingly high steel yield stress. Crack widths in the CRR specimens at service loads were consistent with the Grade 60 control except for the GFRP tests which resulted in cracks approximately twice as wide as the Grade 60 control. A reduction in CRR rebar quantities produced flexural behavior consistent with Grade 60, regardless of the higher yield strengths in CRR specimens. Increasing bar spacing resulted in larger crack widths, whereas decreasing concrete clear cover reduced crack widths. Moment-curvature predictions from the computer-based sectional analysis program Response 2000 were consistent with the tested results, demonstrating its viability for use with high strength and non-metallic rebar without a defined yield plateau.Deformability of the concrete slab-strip specimens was defined with ultimate-to-service level ratios of midspan deflection and curvature. The MMFX2 and Enduramet 32 one-to-one replacement specimens had deformability consistent with or higher than the Grade 60 controls, demonstrating that bridge deck slabs employing high strength rebar without a defined yield plateau can still provide more than sufficient ductility at an ultimate limit state. The GFRP and 2304 one-to-one replacement specimens had less deformability than the Grade 60 control and further consideration is needed to identify a viable bridge deck reinforcing scheme for this bar type. A reduction in rebar quantity and cover provided an acceptable level of ductility for the 2304 specimens and MMFX2 reinforced slabs, however reserve strength should be provided to accommodate moment redistribution at an ultimate limit state.
  Authors: Bowen, Galo; Zheng, Paul; Moen, Cristopher D.; Sharp, Stephen R.
  Authors: Bowen, Galo; Zheng, Paul; Moen, Cristopher D.; Sharp, Stephen R.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 628
  Paper Number: 13-3314
• Roundabout Critical Headway Measurement Based on High-Resolution Event-Based Data from Wireless Magnetometers
  Abstract: Critical headway is an important parameter for roundabout design, particularly in regards to analytical modeling approaches. These models have been developed over the past 30 years and were typically developed using data obtained from manually reduced video and/or field observations. This paper reports on the application of wireless magnetometers to collect point presence detection to calculate the rejected critical headways. Data was collected at a single lane roundabout in Carmel, IN. Carmel, IN is a community with over 60 roundabouts in operation for several years, representing a community highly experienced in using roundabouts. Over 260,000 entering vehicles were observed at one of the single lane roundabouts over a two week period with over 45,000 rejected headways analyzed. For the roundabout studied, 75% of the rejected headways were found to be less than 3.0 seconds. The rejected headways values were somewhat less than reported in NCHRP Report 572, perhaps due to the evolving driver familiarity with using roundabouts in a community with a particularly large number of roundabouts. The rejected headway characteristics observed suggest that as roundabouts become more common throughout the U.S., it may be appropriate to revisit some of the basic traffic engineering parameters used for analysis, much like the traffic signal community did with saturation flow rate in the 1990s. The techniques presented in this paper could be scaled to several roundabouts with varying geometrics and traffic to diversify the data set necessary to update some of the values developed in the last decade before roundabouts were common in the U.S.
  Authors: Hainen, Alexander Michael; Rivera, Erick Manuel; Day, Christopher M.; McBride, Michael Thomas; Grimmer, Gannon; Bullock, Darcy M.
  Authors: Hainen, Alexander Michael; Rivera, Erick Manuel; Day, Christopher M.; McBride, Michael Thomas; Grimmer, Gannon; Bullock, Darcy M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-3316
• Experiments on a Hybrid-Composite Beam for Bridge Applications
  Abstract: This paper details an effort to study the structural behavior of Hybrid-Composite Beams (HCB) consisting of a Fiber Reinforced Polymer (FRP) shell with a tied concrete arch. This beam offers advantages in life cycle costs through reduced transportation weight and increased corrosion resistance. By better understanding the system behavior the proportion of load in each component can be determined, and each component can be designed for the appropriate forces. A long term outcome of this research will be a general structural analysis framework that can be used by DOTs to design HCBs as rapidly constructible bridge components. The specific focus in this study is to identify the load paths and load sharing between the arch and FRP shell in an HCB without a concrete deck. Testing was performed by applying point loads at midspan and quarter points of three simple span beams, resulting in strain data for the arch and FRP shell. The test results show that strain behavior is linear elastic at service loads and the FRP shell has a relatively linear strain profile. Curvature from strain data is used to find internal bending forces, and the proportion of load within the arch is found. Additionally, a stress integration method is used to confirm the internal force contributions. Ultimately, the arch carries about 70% of the total load, but the amount of arch bending and axial force depends on the position of loading. Work is underway to extend this research to the study of load paths and distributions in an HCB with a bridge deck integrally connected to the tied arch.
  Authors: Van Nosdall, Stephen Paul
  Authors: Van Nosdall, Stephen Paul
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 426
  Paper Number: 13-3318
• Influence of Bridge Facility Attributes on Bicycle Travel Behavior
  Abstract: This paper develops an unlabeled multinomial logit model to estimate the impact bridge facility attributes have on bicycle travel behavior. The data used to estimate the model was collected May through October 2011 in Austin, Texas via a GPS-based smartphone application that allowed trips to be tracked in real-time. Demographic (age, gender, and cycle frequency) and trip purpose information was also collected. Three attributes are analyzed in the model: bridge accessibility/connectivity to the bicycle network, vehicular volume, and bicycle separation from traffic. Accessibility and bicycle separation significantly impacted bicyclists’ behavior, especially for comfort-prone users (female and infrequent bicyclists) as well as for trips where travel time is not a significant issue. Distance was found to be the most significant factor, particularly for time-constrained trips (trips during the peak period and commute trips). Distance was less important for recreational trips as well as for female bicyclists.
  Authors: Melson, Christopher L.; Duthie, Jennifer; Boyles, Stephen
  Authors: Melson, Christopher L.; Duthie, Jennifer; Boyles, Stephen
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-3358
• Nondestructive Evaluation Of Concrete Linings At Hanging Lake Tunnel
  Abstract: Tunnel lining evaluation is performed in the Hanging Lake Tunnel near Glenwood Springs, Colorado, using variations of four nondestructive evaluation (NDE) methods: air- and ground-coupled ground penetrating radar (GPR), ultrasonic echo (US echo), ultrasonic tomography (UST), and impact echo (IE). Potential regions of interest are identified using high-speed air-coupled GPR and visual inspection. A robotic frame with pneumatically-operated vacuum plates was used to automate the ground-coupled GPR, US echo, and IE tests, while the UST technique was used manually. This study shows that a particular combination of NDE techniques is a powerful tool for assessing the condition of tunnel linings and can detect potential anomalies such as delamination, depth of surface cracks, reinforcement depth and layout, and lining thickness. By mapping the phase shift of the ultrasonic pulses at detected interface, the potential bonding of layer interfaces and reinforcement is assessed.
  Authors: White, Joshua; Wolf, Julia; Shokouhi, Parisa; Hurlebaus, Stefan; Wimsatt, Andrew James
  Authors: White, Joshua; Wolf, Julia; Shokouhi, Parisa; Hurlebaus, Stefan; Wimsatt, Andrew James
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: AFF60
  Paper Number: 13-3362
• Effect of Left-Turn Operational Mode on Pedestrian Safety: Development of Models and Guidelines
  Abstract: Pedestrian safety is a growing concern at signalized intersections. Pedestrians crossing a street at an intersection are exposed to interactions with turning vehicles, and these interactions sometimes result in crashes. Conflicts and crashes can be reduced by implementing protected turn phases. However, the inclusion of protected turn phases in a traffic signal cycle typically causes an increase in vehicular delay, which tends to offset the benefit of reduced crashes.Left-turn operational mode (permissive, protected-permissive, or protected) is typically chosen based on vehicular traffic concerns like volumes of left-turning and conflicting through vehicles, lane geometry, and sight distance. Historically, pedestrian safety has not been considered as a factor in selecting left-turn operational mode.Pedestrian safety models have been calibrated using field data. The models allow pedestrian-vehicle conflict frequency and pedestrian compliance with signal indications to be estimated based on volumes and site conditions. These models, along with vehicular delay analysis, form the basis for pedestrian-safety-based guidelines that were developed for choosing left-turn operational mode. The guidelines are based on identifying threshold conditions for which a change in left-turn mode results in a reduction in road-user costs.
  Authors: Pratt, Michael Paul; Bonneson, James A.; Songchitruksa, Praprut
  Authors: Pratt, Michael Paul; Bonneson, James A.; Songchitruksa, Praprut
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3370
• Concrete Tunnel Lining Evaluation Using Nondestructive Techniques: Multimethod Case Study at Eisenhower Tunnel, Colorado
  Abstract: An in-depth investigation of tunnel linings is performed at Eisenhower Tunnel 60 miles west of Denver, Colorado, using a combination of four nondestructive testing methods: air- and ground-coupled ground penetrating radar (GPR), ultrasonic echo (US echo), ultrasonic tomography (UST), and impact echo (IE). A robotic frame with pneumatically operated vacuum plates is used to automate GPR, US echo, and IE. UST was performed manually. These techniques are used to identify and locate the reinforcement mesh and structural steel ribs. By analyzing the phase shift from the ultrasonic data, it is also possible to estimate the bond between the concrete and the embedded steel. It is shown that this combination of methods can be used synergistically to provide tunnel owners with the layout and possible condition of tunnel lining reinforcement and structural components.
  Authors: White, Joshua; Wolf, Julia; Shokouhi, Parisa; Hurlebaus, Stefan; Wimsatt, Andrew James
  Authors: White, Joshua; Wolf, Julia; Shokouhi, Parisa; Hurlebaus, Stefan; Wimsatt, Andrew James
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 269
  Paper Number: 13-3381
• Geospatial Analysis of Pedestrian and Cyclist Crashes in Urban Environment: Case Study
  Abstract: Most urban dwellers today do not need to be convinced of the benefits of walking and cycling, which range from improving health and refining the environment to easing traffic congestion and improving a community’s economy. While practices and policies have been established to promote these transportation modes, many challenges still exist which restrain this growth in practice. To identify some of these challenges, the authors performed pedestrian and cyclist safety analyses in an urban center, the city of Hoboken, New Jersey, where potential demands were anticipated. Having the Hoboken terminal as a major intermodal regional hub in this city, the authors performed geospatial safety analyses of pedestrians and cyclists in the vicinity of this terminal. The findings revealed that the number of pedestrian and cyclist injuries decreased as the distance from the Hoboken terminal increased. The frequency of injury was also normalized against population and land use characteristics. While the estimated rates roughly follow the trend of injury frequency, more investigations have been performed to discover contributors such as inadequacy of pedestrian facilities, ambient lighting, and traffic controls at intersections, which may elevate crash exposure risks. The investigation also showed that there was a correlation between the location of bus stops and pedestrian injuries/fatalities, particularly at a further distance from the Hoboken terminal. The study of pre-crash actions and crash-contributing circumstances suggested that pedestrian safety was in jeopardy mostly at intersections and particularly at crosswalks. The same assessments were also carried out for cyclists and cyclist facilities. Safety analyses suggested that an establishment of dedicated bike lanes had improved safety at the test-bed area; however, more enhancements were required to foster this transport mode.
  Authors: Moini, Nadereh; Liu, Rongfang
  Authors: Moini, Nadereh; Liu, Rongfang
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3389
• Improving the Quality of Profile Measurements by Lifting Wavelet Filters
  Abstract: Profile measurement activities called as profiling require algorithms to eliminate unwanted noise and to extract the information of interest from measured data for the calculation of International Roughness Index (IRI) as well as any roughness index. Pavement cracks particularly cause problems in the calculation. Although a low-pass gsmoothingh filter will reduce a large dip caused by a crack included in a profile, conventional filtering algorithms do not completely remove the influence of cracks. This study develops a new smoothing algorithm using the lifting scheme theory to improve the quality of profile measurements. The procedures for developing the algorithm include (1) learning free parameters by using training signals, and then (2) constructing lifting wavelet filters. The filters are especially intended to remove the influence of cracks in profile measurement data. This paper also provides a profile-smoothing simulation study to demonstrate the advantages of the lifting wavelet filters over conventional digital filters such as the moving average and Butterworth filters. The results indicate that the lifting wavelet filters are superior in eliminating the influence of cracks for roughness evaluation to the conventional filtering algorithms. Finally, we conclude that the lifting wavelet filters allow profile users to improve the quality of profile measurements for the roughness evaluation such as IRI calculation. The findings of this study contribute to many applications related to pavement management such as surface monitoring, development of measurement devices, and interaction analysis between surface properties and vehicles.
  Authors: Tomiyama, Kazuya; Kawamura, Akira; Ishida, Tateki
  Authors: Tomiyama, Kazuya; Kawamura, Akira; Ishida, Tateki
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 241
  Paper Number: 13-3405
• Study on Pedestrian Red Light Crossing Violation Behaviors: Observation at Four-Phase Signalized Intersections in Shanghai, China
  Abstract: Pedestrian violation is a major cause of traffic accidents involving pedestrians. The research objectives were to investigate the relationship between crossing time gap and pedestrian violation and to provide a qualitative and quantitative analysis of the effects of human factors and external environmental factors on red light crossing behavior. Pedestrian red light crossing gap was collected by video cameras and it was assigned as rejected and accepted data to distinguish between normal crossing and violating crossing. Two methods were used to acquire the RLC critical gap. A multiple linear regression model was introduced, and variables revealing personal characteristics, traffic conditions, and trip features were defined as covariates to describe the effects of internal and external factors. The study concluded that Harder¡¯s method is good for getting the RLC critical gap and when time gap is larger than 6.12s violations become more and more. The pedestrian RLC time gap is related with weather, age, group size and violating whether at the beginning of red light time, and it is not related with gender, violation stage and other factors. To improve the safety condition of the intersection well signalized timing and good management are dire in need.
  Authors: Bai, Yu; He, Xiong; Long, Li; Xiaoguang, Yang
  Authors: Bai, Yu; He, Xiong; Long, Li; Xiaoguang, Yang
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3465
• Using Microsimulation to Support Decisions on Transport Infrastructure Planning: Case Study
  Abstract: Through a case study, this paper demonstrates the approach of using micro simulation tools in supporting urban infrastructure planning decisions. The study shows that the approach has great advantages over the current decision making support mechanism: it has large flexibility, it is technically sound, it can be done very quickly, and its powerful visualization capability can significantly reduce the communication gap between technical people and decision makers. While it lacks field observations during infrastructures¡¯ planning stage, micro simulation is usually able to pick up the performance differences for various alternative plans by using some default or assumed parameters and input data based on engineering judgment or practice manual assumptions. In the case study, using the simulation result, the authorities were quickly convinced to adopt a better alternative. It turned out that the approach is quite effective and worth some attention.
  Authors: Wang, Zhigao; Tang, Chong; Shen, Feng
  Authors: Wang, Zhigao; Tang, Chong; Shen, Feng
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 679
  Paper Number: 13-3672
• Structural Evaluation of Pervious Concrete in Pavement Test Sections
  Abstract: An evaluation was made of the structural capacity of pervious concrete pavement on three base types including, virgin aggregate, recycled concrete aggregate, and Cellular Lightweight Permeable Concrete (CLPC). The objective was to determine the structural capability of pervious pavement to handle moderate truck traffic on city streets and low volume roads. Structural testing was performed using the Falling Weight Deflectometer (FWD). The FWD tests were performed on five pervious pavement test sections representing the three base types. Tests were also performed on a conventional concrete (PCC) pavement with stabilized base and results were used as a reference for structural capacity assessment of the pervious sections. The maximum FWD deflections and the deflection profiles of the different pavements sections were analyzed by comparing the deflection data among the various sections and the conventional concrete pavement. Results of the evaluation indicated that the pervious concrete pavement on CLPC has equal structural capacity to that of the previous concrete on aggregate base, and a higher structural capacity to that on recycled concrete base. The results also showed that the structural capacity of pervious concrete is adequate to handle moderate truck traffic on streets and low volume roads.
  Authors: Armaghani, Jamshid M.
  Authors: Armaghani, Jamshid M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 554
  Paper Number: 13-3673
• Stepping off the Curb to Increase Drivers’ Yielding Behavior at Midblock Crosswalks
  Abstract: Interaction between pedestrians and drivers can be witnessed everywhere in the road network, particularly at intersections and mid-block crossings. At unsignalized mid-block crosswalks, drivers typically don’t expect pedestrians, and as a result, pedestrian safety may be compromised. The yielding behavior is affected by various aspects of the roadway and driving environment, including vehicle dynamics, pedestrian’s behavior, roadway function and design. Traditional roadway design indicates that if a driver has adequate sight distance to the crosswalk, then he or she should stop for the pedestrian. This paper focuses on two discrete crossing behaviors - pedestrians standing on the curb; and the other was that pedestrians had stepped off the curb. The data were collected in Boston, MA during the AM and PM peak on a typical weekday. The results show that fewer drivers yielded to pedestrians who were standing on the curb, versus those that were standing in the crosswalk (8.5% of the drivers yielded to pedestrians on the curb and 21.7% yielded when pedestrians had stepped off the curb). Regardless of pedestrian location, more drivers yielded the right of way during the AM peak as compared to the PM peak.
  Authors: Dulaski, Daniel M.
  Authors: Dulaski, Daniel M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-2975
• Externally Bonded GFRP and NSM Steel Bars for Enhanced Strengthening of Concrete T-beams
  Abstract: The technology of FRP strengthening has matured to a great extent. However, there is always room for performance improvements. In this study, external bonding of GFRP and near surface mounting of regular steel bars is combined to improve the behavior, delay the failure and enhance the economy of the strengthening. E-Glass FRP is selected due to its inexpensive cost and non-conductive properties to shield the NSM steel bars from corrosion. On the other hand, the use of NSM bars gives redundancy against vandalism and environmental deterioration of GFRP. An experimental program is conducted in which four T beams are designed and built. The first beam is tested as a control beam failing at about 15 kips. The second beam is strengthened using 5 layers of CFRP, which failed at 25.5 kips by CFRP debonding. The third beam is strengthened using two #5 steel NSM bars and 1 layer of GFRP, both extending to the support. This beam failed at 38.4 kips by GFRP and NSM debonding. The fourth beam is strengthened with the same system used for the third beam. However, the NSM steel bars were cut short covering only 30% of the shear-span while the GFRP was extended to the support. This beam failed at 25.9 kips by GFRP debonding and NSM delamination due to the lack of sufficient development of the NSM steel bars and the shear stress concentration at the steel bar cut off point. Nevertheless, the failure load developed was comparable to 5 layers of CFRP used for beam 2.
  Authors: Traplsi, Abdelbaset; Wuertz, Augustine; Rasheed, Hayder; AlKhrdaji, Tarek
  Authors: Traplsi, Abdelbaset; Wuertz, Augustine; Rasheed, Hayder; AlKhrdaji, Tarek
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Materials
  Session: 461
  Paper Number: 13-3120
• Responses and Performance of Stabilized Full-Depth Reclaimed Pavements at MnROAD
  Abstract: This paper details the efforts regarding the construction and analysis of three stabilized full-depth reclamation (SFDR) sections (cells 2, 3, and 4) constructed at the Minnesota Road Research Facility (MnROAD) on I-94 in 2008. Three test sections with varying pulverized asphalt concrete/granular base ratios were constructed in order to study the performance of full-depth reclaimed (FDR) pavements stabilized with engineered emulsion. Emulsion content and base structure varied between test sections. Each test section was designed for 3.5 million ESALs over a period of five years. The sections have been subjected to approximately 2.2 million ESALs as of 30 June 2012.Strain gages were embedded at the bottom of the hot-mix asphalt (HMA) and SFDR layers in each test section to measure responses. The strain gages indicate that both the bottom of the HMA and SFDR layers are subject to horizontal tensile strain from falling weight deflectometer (FWD) and heavy vehicle loading. Pavement performance in terms of rutting, cracking, and international roughness index (IRI) has been measured periodically. The results indicate that all three cells are performing well. The only crack in the three cells exists in cell 3, IRI values are well within the acceptable range, and rutting, while progressing, is still acceptable. Finally, the paper concludes with modeled responses and performance predictions from DARWinME and BISAR. Model predictions indicate that a SFDR layer will provide greater structural benefits and increased performance than similar structures with unstabilized FDR or granular base layers.
  Authors: Johanneck, Luke A; Dai, Shongtao
  Authors: Johanneck, Luke A; Dai, Shongtao
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 555
  Paper Number: 13-3135
• Patch Analysis of Reinforced-Concrete Bridge Decks Using Ground-Penetrating Radar
  Abstract: The common practice of patching decayed or damaged bridge decks introduces unique challenges to non-destructive testing (NDT) techniques when the deck is extensively patched. NDT techniques are useful to gain knowledge of damaged bridge decks, but it is important to know their limitations to correctly assess the condition and remaining life of the structure. Three bridge decks in the New England area were subjected to a suit of testing which included ground penetrating radar, half cell potential, chain drag/hammer sounding, visual inspection and core sampling. Two of the three decks had large patched areas. The data from each of the tests, specifically ground penetrating radar and half-cell potentials, allow for the comparison and the identification of the limitations of each individual test. Using the gained knowledge of the shortcomings of individual tests, it allows the data interpreter to identify ways to compensate for the unique difficulties caused by patched bridge decks. With a better understanding of the data collected from NDTs, higher precision QC/QA can be performed, which can lead to increased savings and higher durability of the bridge decks.
  Authors: Martino, Nicole; Vilbig, Reid; Birken, Ralf; Maser, Kenneth R.
  Authors: Martino, Nicole; Vilbig, Reid; Birken, Ralf; Maser, Kenneth R.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 500
  Paper Number: 13-3242
• Incorporation of Mechanistic-Empirical Faulting Model into Design of Composite Pavements
  Abstract: This paper describes the development of an approach for the prediction of faulting in the concrete layer of composite pavements, which for this paper are taken to be asphalt concrete (AC) overlays of existing Portland cement concrete (PCC) pavements. Currently the Mechanistic-Empirical Pavement Design Guide considers faulting only for jointed plain concrete pavement (JPCP) projects and does not consider faulting for AC-PCC pavements, which does not permit rational design of dowels in the PCC layer. The paper briefly details the original MEPDG JPCP faulting model. Modifications to this model for the benefit of AC-PCC projects are introduced and detailed, and a procedure is described that incorporates this new model into the existing MEPDG framework. The overall goal was to provide a procedure for faulting in AC-PCC design and analysis for pavement engineers that does not require uncommon inputs and does not force the user outside of the MEPDG framework. The paper also describes a sensitivity analysis of the developed procedure for faulting in AC-PCC. It is hoped that the developed procedure represents a step forward for the design and analysis of composite pavements using the MEPDG.
  Authors: Khazanovich, Lev; Tompkins, Derek; Clyne, Timothy R.
  Authors: Khazanovich, Lev; Tompkins, Derek; Clyne, Timothy R.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 441
  Paper Number: 13-3271
• Field and Software Evaluation of Illuminance from LED Luminaires for Roadway Applications
  Abstract: An evaluation of the illuminance from LED roadway luminaires was conducted using field measurements and lighting analysis software. Three sets of recently-developed LEDs and one set of HPS luminaires were installed in the field and repeated sets of data were collected for each set following IESNA LM-50-99 standard procedures. Field illuminance datasets were compared with expected performance of the luminaires based on AGi32 software using the photometry provided by the manufacturers. Results showed that illumination values from the field were at some points lower than those from software calculations, and these differences varied both in magnitude and location depending on the LED luminaire. Multiplicative factors to describe the differences were estimated and ranged from 0.96 (relatively small differences) to 0.57 (relatively large differences), with larger differences located at points near the light poles, and at middle and third points of the span. This suggests that quick checks can be performed by taking illuminance measurements at key points along the span to provide an approximation on the actual differences between field and software results for the whole grid. Discrepancies between software and field data may play a very important role in the use of the luminaires for a given road and pedestrian conflict classification, as the illuminance in the field may not reach minimum levels required by public agencies. An example using minimum requirements from the Illinois Department of Transportation is provided to illustrate this point. Full sets of repeated field data points following IESNA LM-50-99 are not commonly collected at new or upgraded installations, and moreover, using state-of-the-art luminaires, increasing the potential usefulness of the data and the comparisons included in this paper for practitioners and researchers alike.
  Authors: Medina, Juan C.; Avrenli, Kivanc A.; Benekohal, Rahim F.
  Authors: Medina, Juan C.; Avrenli, Kivanc A.; Benekohal, Rahim F.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-3398
• Viscoelastic Genetic Algorithm for Inverse Analysis of Asphalt Layer Properties from Falling Weight Deflections
  Abstract: Falling Weight Deflectometer (FWD) is a nondestructive test typically used to backcalculate layer properties of in-service pavements. Most backcalculation methods assume the pavement to be layered elastic structure. However, asphalt pavements are multilayered viscoelastic systems and their response under small load level is primarily viscoelastic. Hence, although elastic analysis is computationally efficient, they don’t produce the fundamental material properties such as the complex modulus E* or creep compliance D(t). On the other hand, there are dynamic backcalculation methods that can consider the asphalt pavements as viscoelastic, however they are computationally inefficient and inaccurate if the FWD deflection time history is truncated. Furthermore, most existing methods either ignore the asphalt concrete (AC) temperature or assume the entire depth of the AC layer to be at a constant temperature. In this study, a new inverse analysis method is proposed to backcalculate linear viscoelastic pavement layer properties (i.e., E(t)) as well as the time-temperature superposition shift factor coefficients. In this method, FWD load-response history of a single FWD drop and variation in temperature along the depth of AC layer during the drop are used. Genetic algorithm based optimization scheme is offered to search for the pavement properties, which has the potential of converging to a global solution. As an example, two LTPP sections are selected for backcalculation. The results are positive, indicating that there is a possibility to backcalculate AC properties from a single FWD drop, provided the effect of dynamics is insignificant during the test.
  Authors: Varma, Sudhir; Kutay, Muhammed Emin; Levenberg, Eyal
  Authors: Varma, Sudhir; Kutay, Muhammed Emin; Levenberg, Eyal
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 665
  Paper Number: 13-4091
• Matched Filtering Algorithm for Pavement Cracking Detection
  Abstract: There have been rapid developments of automated cracking survey for pavements in recent years. Especially the introduction of laser-imaging technology has made the acquisition of shadow-free images feasible. However, due to the complexity of pavement surface, diverse characteristics of cracks, presence of foreign objects, and varying identification protocols, the results of fully automated technologies for cracking survey have only been used on limited basis. This paper introduces a novel detection theory, matched filtering algorithm, into pavement cracking detection as part of an effort to improve precision and bias levels of the fully automated system. Unlike traditional edge detection approaches which adopt first- or second-order derivatives of image signals, the matched filtering algorithm detects cracks by matching pre-designed filters with crack features in terms of shape, orientation and intensity. Experimentations are conducted and detection results are compared between the five traditional edge detectors (Robert, Prewitt, Sobel, LoG and Canny) and the matched filtering algorithm. It is demonstrated that the matched filtering algorithm is a robust approach to detecting cracks and has better performance in noise removal and cracking detection. With matched filters aligned at different orientations, this algorithm shows its distinctive advantages at extracting a single crack as it is, and recording the crack’s orientation to be used for more accurate classification in the next step of automated processing.
  Authors: Zhang, Allen; Li, Qiang; Wang, Kelvin C. P.; Qiu, Shi
  Authors: Zhang, Allen; Li, Qiang; Wang, Kelvin C. P.; Qiu, Shi
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 475
  Paper Number: 13-4077
• Modeling of Pedestrian Unsafe Road Crossing Behavior: Comparison at Signalized and Nonsignalized Crosswalks
  Abstract: Background: Many pedestrians are found to indulge in unsafe road crossing at both the signalized and non-signalized crosswalks.Objective: To study and compare unsafe pedestrians’ crossing behaviour at a signalized and/or a non-signalized crosswalk.Method: F and t tests are performed to observe which crosswalk has the larger mean and variance of the available gap-size in the traffic flow and waiting time of pedestrians. Logistic regression models are fitted to examine the pedestrians’ risk and unsafe road crossing behavior at two crosswalks.Results: Mean and variance of available gap size and waiting time to pedestrian at a signalized cross walk is larger than a non-signalized crosswalk. At a signalized crosswalk, probability of crossing by a pedestrian with the gap size less than the adequate gap size is about 98%; and at a non-signalized crosswalk it is about 95%. At a signalized crosswalk only gap size parameter is significant. However, at a non-signalized crosswalk other predictor parameters (such as gender of the pedestrian, whether alone or in a group, type of the conflicting vehicle and traffic volume) are significant in determining the pedestrian road crossing behavior. The odds of an unsafe road crossing by a pedestrian at a signalized crosswalk is about 1.7 times higher than that at a non-signalized crosswalk.Conclusion: Pedestrians unsafely cross roads when gaps are available within the traffic flow, at both signalized and non-signalized crosswalks. Thus gap size is a significant parameter to determine the pedestrians’ unsafe road crossing behaviour at both crosswalks.
  Authors: Khatoon, Mariya
  Authors: Khatoon, Mariya
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-4086
• Experimental Evaluation of Connections in Hybrid FRP-Concrete Bridge Truss Girders
  Abstract: An innovative corrosion-free precast prestressed concrete truss girder has been developed for short- and medium-span slab-on-girder bridges. The girder consists of top and bottom concrete flanges connected by precast vertical and diagonal members made of fiber reinforced polymer (FRP) tubes filled with concrete. The verticals and diagonals are connected, respectively, to the concrete flanges by means of glass FRP dowels and stud reinforcement made of corrosion-resistant steel or FRP material. The flanges are pretentioned with carbon FRP tendons. The deck slab is reinforced with corrosion-resistant steel bars in the bottom transverse layer and with glass FRP bars in the bottom longitudinal and the top layers. The girders may be post-tensioned with external carbon FRP tendons to balance the slab weight and to provide continuity in multi-span bridges. The new system has the advantages of light weight and enhanced durability. The light weight reduces the initial cost and allows for longer spans. The improved durability reduces the maintenance cost and extends the structure’s life span. This paper describes the general details of the system and presents an experimental evaluation of its critical components, namely, the FRP tubes and the truss connections. Two types of FRP tube and four types of connection are investigated. Results of testing eight connection specimens under static loading and four specimens under fatigue are presented. The tests have shown excellent performance of the connection when filament wound tubes and continuous double-headed studs are used.
  Authors: El-Badry, Mamdouh; Schonknecht, Kyle; Abe, Hiroyuki
  Authors: El-Badry, Mamdouh; Schonknecht, Kyle; Abe, Hiroyuki
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Materials
  Session: 461
  Paper Number: 13-4134
• Development of Climate Zones for DARWin-ME
  Abstract: The Enhanced Integrated Climatic Model (EICM) integrated in the DARWin-ME design procedure allows users to select adjacent weather stations to generate a virtual weather station (VWS), whose data are further used to predict environmental impact on pavement performance. The DARWin-ME approach doesn't fully consider the potential spatial variations among these adjacent stations. Therefore, developing climate zones within a state may be necessary to account for the different climatic patterns and improve the accuracy of generated climate data. In this paper, using climate data from the National Climatic Data Center (NCDC), a cluster analysis technique is applied to develop climate zones for the State of Oklahoma. Consequently, climatic data from NCDC, DARWin-ME site-specific weather station, DARWin-ME interpolation approach using adjacent stations, and interpolation using stations within the same climate zone are obtained and compared. It is anticipated that the virtual weather data generated from the approach developed in this paper will provide more accurate data than those using the built-in DARWin-ME database and approach. However, due to the fact that Oklahoma is one of the most geographically flattest states in the US and the spatial variations within the states are insignificant, only minor improvements are obtained using the proposed technique in the DARWin-ME analyses. It is identified in the paper that selecting 5 to 10-year period of climate history data provided in DARWin-ME to generate climate data for a 20 to 40-year pavement design is inadequate. It is recommended that further work needs to be conducted in the states where substantial spatial variations are present.
  Authors: Li, Qiang; Wang, Kelvin C. P.; Zhang, Jun
  Authors: Li, Qiang; Wang, Kelvin C. P.; Zhang, Jun
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 236
  Paper Number: 13-4149
• Pedestrian Crossings at Midblock Locations: Comparative Study of Existing Signal Operations
  Abstract: The increasing accidents happen at mid-block crossings (MBCs) have led traffic engineers to consider treatments to make crossings safer. One common method is to install signalized MBCs. Until now, there are four mature signal control systems at MBCs that currently used in the U.S. , Great Britain and some other countries which are pedestrian actuated (PA), pedestrian light controlled (PELICAN), high intensity activated crosswalk (HAWK) and pedestrian user-friendly intelligent (PUFFIN). Efficiency evaluation of these methods also has been carried out, however, most of the previous studies based on the hypothesis that pedestrians proceed under green signal, but in reality it is very common to see pedestrians enter crossings during pedestrian clearance interval, which is supposed to weaken the effectiveness and safety at crossings.With a strictly calibrated VISSIM model and SSAM software, the research explores how signalization schemes, pedestrian clearance interval violation rates, traffic flow and geometries affect the efficiency and safety of all road users at MBCs, in order to provide traffic engineers some guidance to select proper methods. Based on a Pearson-correlation analysis and multiple linear regression model, it is found that pedestrian signal violation during clearance interval can slightly reduce pedestrian delay, but results in a rapid increase on pedestrian-vehicle conflicts, especially for HAWK. The final results show that PA leads to high delay of both pedestrians and vehicles but less conflicts, PELICAN is beneficial for vehicular traffic by reducing vehicle delay but unbeneficial for pedestrian traffic since pedestrian delay is always high. HAWK and PUFFIN are better than the above two methods from balancing safety and efficiency for all road users. HAWK has a satisfactory performance at low pedestrian flow but it attributes to more conflicts when pedestrian flow increase up to ¡°middle¡± and ¡°many¡±, especially when pedestrian clearance interval violation rate is high. However, PUFFIN has a better performance than HAWK from both perspectives when pedestrian volume is ¡°middle¡± and ¡°many¡± .
  Authors: Deng, Tengyun; Ni, Ying; Li, Keping
  Authors: Deng, Tengyun; Ni, Ying; Li, Keping
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3341
• Evaluation of Seasonal Variation in Pavement Mechanistic Responses Using Falling Weight Deflectometer Data
  Abstract: Pavement structures in regions with severe and frequent freeze and thaw cycles are prone to prompt damage. The pavement structure is in its weakest conditions right after the start of the thawing season each year. The existing practice followed by many highway agencies is to enforce spring road ban (SRB) during the critical thawing period. Alberta Transportation performs an extensive Falling Weight Deflectometer (FWD) test program during the spring to enhance SRB decision making process. In this study, the results from the FWD tests for multiple highway sections in Alberta from 2000 and 2006 were analyzed to investigate the effect of seasonal variation on pavement stiffness and mechanistic responses. The FWD data was used to backcalculate the pavement layers’ moduli and to predict two critical pavement responses of tensile strain at the bottom of the Asphalt Concrete layer and compressive strain at the top of the subgrade in spring and summer. The Asphalt Institute’s predictive models for fatigue cracking and rutting failures were used to relate the pavement responses to the allowable number of load repetitions (Nf for fatigue and Nd for rutting). The comparison of Nf and Nd between the spring and summer shows differences of as high as 88 percent for Nf and 98 percent for Nd. Further analysis showed that a 50% reduction in the load during the critical period of spring can result in about a 90% increase in the Nd and Nf.
  Authors: Norouzi, Meisam; Nassiri, Somayeh; Bayat, Alireza
  Authors: Norouzi, Meisam; Nassiri, Somayeh; Bayat, Alireza
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 480
  Paper Number: 13-3346
• Evaluation of Pedestrian Safety: Geographical Identification of Pedestrian Crash Hotspots and Evaluating Risk Factors for Injury Severity
  Abstract: Pedestrian-involved crashes that occurred in the city of San Francisco over six years from 2002-2007 were analyzed to evaluate two key aspects of pedestrian safety: occurrence and severity. This was done to identify locations with frequent occurrences of pedestrian-involved crashes and to examine various risk factors on the injury severity of pedestrian-involved crashes. A Geographical Information System (GIS) analysis used for the former shows that the frequency of pedestrian crashes is higher in the vicinity of the central business district, while the rate is higher in the periphery of the city. The latter specifies an ordered probit model to evaluate risk factors that increase the probability of severe injury and fatality. Those factors were: i) age (<15 and 65+), alcohol consumption and cell-phone use among pedestrian characteristics; ii) nighttime, weekends and rainy weather among environmental characteristics; and iii) influence of alcohol, larger vehicles (pickup, bus and truck) and vehicle proceeding straight in striking a pedestrian among crash characteristics. The methods discussed in this paper are readily applicable to evaluation of safety performance in other regions where pedestrian crash data are available.
  Authors: Jang, Kitae; Park, Shin Hyoung; Kang, Sanghyeok; Song, Kihan; Kang, Seungmo; Chung, SungBong
  Authors: Jang, Kitae; Park, Shin Hyoung; Kang, Sanghyeok; Song, Kihan; Kang, Seungmo; Chung, SungBong
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3433
• Environmental Analysis of Asphalt Pavement Maintenance Using Modified Binders in Developing Countries: Case Study in Bogotá, Colombia
  Abstract: This study presents an environmental analysis of four maintenance alternatives for a case study to be conducted in Bogotá, Colombia. The study involves a conventional hot-mix asphalt (CHMA), a polymer-modified hot mix with styrene butadiene styrene (PM-SBS) and two crumb rubber asphalt mixes, asphalt rubber dense-graded (AR-DG), and asphalt rubber gap-graded (AR-GG). This paper presents an analyzes of the environmental impacts of these maintenance options by using the Eco-indicator99 as a life-cycle inventory -tool (LCIT). The analysis is complemented by estimations of the global-warming potential (GWP) index and energy consumption of each option. Two scenarios and their environmental impacts were considered: using 1) heating oil (HO) or 2) natural gas (NG) as fuel for drying and mixing in an asphalt plant. Also, the binder transportation was analyzed with the consideration that, in Colombia, there are only two national refineries with binder production to cover the country demand. The impacts of a polymer-modified plant (PMP) and the tire-shredding process were considered as well. The results showed that the production of materials contributed roughly 55% to 65% of environmental load (EL), and heating aggregates contributed almost 29% of EL. Maintenance conducted using AR-GG was considered the more eco-efficient option with the lowest EL, on the other hand AR-DG, and PM-SBS showed to have similar EL.
  Authors: Martinez-Arguelles, Gilberto; Crispino, Maurizio; Giustozzi, Filippo; Flintsch, Gerardo W.
  Authors: Martinez-Arguelles, Gilberto; Crispino, Maurizio; Giustozzi, Filippo; Flintsch, Gerardo W.
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Pavements
  Session: 705
  Paper Number: 13-3475
• Key Techniques in Design of Sutong Yangtze River Highway Bridge, China
  Abstract: Sutong Yangtze River Bridge is the longest cable-stayed bridge existing in the world with main span of 1088m. This paper briefly introduces the main technical characteristics of its important design points as steel box girder, stayed cable, steel anchor box for main pylon, foundation for main pylon, structural system of pylon and beam and anti-collision system for main pylon foundation.
  Authors: Zhang, Xigang
  Authors: Zhang, Xigang
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 220
  Paper Number: 13-3531
• Closure Technique for Hybrid Girder Cable-Stayed Edong Bridge, China
  Abstract: Based on Edong Yangtze River Bridge, the second longest hybrid girder cable-stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long span hybrid girder cable-stayed bridge are studied. According to theoretical analysis, numerical evaluation and practical test, the loading assistant closure method with better thermal adaptability and less influence on bridge line and the forced status is employed in Edong Yangtze River Bridge in order to meet the requirements of the unstressed state control method. Based on the mentioned advantages, the loading assistant closure method is applicable to long span hybrid girder cable-stayed bridges. The conclusion can provide a reference for the further design of the similar bridges.
  Authors: Xu, Guoping
  Authors: Xu, Guoping
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 220
  Paper Number: 13-3540
• Homogeneous Road Segment Identification Based On Inertial Operating Speed
  Abstract: Geometric design consistency evaluation is an important tool for the road safety evaluation of a road alignment. This evaluation determines the grade of fitting between road behavior and drivers’ expectations. Therefore, road consistency and road safety are related: a high consistency level leads to lower crash rates.While local consistency models only focus on a road section, such as curves or tangent-to-curve transitions, global consistency models consider the whole road segment. They evaluate the dispersion of the road segment operating speed profile, assuming that highly variable operating speed profiles increase the probability of accident occurrence.The result of those methodologies varies depending on the selection of the road segment. They should be applied to homogeneous road segments. Some methodologies are already established for splitting the road into homogeneous segments, but they are only focused on some geometric or traffic related variables.A new performance-based methodology for determining road homogeneous segments is presented. It is based on a new variable: the inertial operating speed, defined as the 1,000 m moving average value of the operating speed. It is an indicator of the behavior of drivers during last 1,000 m, allowing its comparison with the local requirements and, therefore, allowing a road consistency evaluation. Identifying significant minimum points located along inertial operating speed profile allows determining homogeneous road segments, using those points as limits between segments.
  Authors: Garcia, Alfredo; Llopis-Castello, David; Perez-Zuriaga, Ana Maria; Camacho-Torregrosa, Francisco Javier
  Authors: Garcia, Alfredo; Llopis-Castello, David; Perez-Zuriaga, Ana Maria; Camacho-Torregrosa, Francisco Javier
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 727
  Paper Number: 13-3545
• Design and Construction of Steel Box Girder for Jiashao Bridge, China
  Abstract: The main navigation bridge for Jiashao Bridge is a steel box girder, six-single-pylon, four-plane cable stayed bridge with span arrangement of 70+200+5¡Á428+200+70=2680m. It is the largest multi-pylon cable stayed bridge worldwide currently with steel box girder width of 55.6m, total bridge length of 2680m, the longest longitudinal slope for bridge deck of 0.45%, and total steel consumption of 77,000 ton. The main characteristics for separated carriage box girder structure are: the width of one carriage is more wider which reaches 24m; the distance between left and right carriages is bigger which reaches 9.8m; the four cable planes make left and right carriages have a relatively independent loads carrying state; rigid hinges are used in span middle of the whole bridge. This paper introduces the design and construction for steel box girder of Jiashao Bridge, including the erection of girder segments in no cable area, cantilevered assembling erection of four-plane steel box girder, and the closure plan for steel box girder of multi-pylon cable stayed bridge.
  Authors: Wang, Rengui
  Authors: Wang, Rengui
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 220
  Paper Number: 13-3548
• Application of Innovative Technology in Baling River Bridge Design, China
  Abstract: Baling River Bridge is the longest span steel truss girder suspension bridge in China. This bridge crosses valleys in mountainous zone of west China where mountains are high and slopes are steep. The clearance between the bridge deck and valley bottom is approximately 370m without water under the bridge, which brought about a number of difficult issues to the construction of both superstructure and substructure. This article introduces how a number of innovations in the design technologies had been developed in the course of design of Guizhou Baling River Bridge on the bases of the bridge construction conditions and the implementation of ¡°safe, applicable, economical and aesthetically pleasing¡± design philosophies for the reasonable determination on the proposed bridge type.
  Authors: Peng, Yundong
  Authors: Peng, Yundong
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 220
  Paper Number: 13-3556
• Key Technology in Steel Box Girder Design of Huangpu South Branch Bridge, China
  Abstract: Huangpu South Branch Bridge is a single span steel box girder suspension bridge with main span length of 1108m. A series of key technologies have been used in the steel box girder design. According to the results from wind resistant test study the external shape of aerodynamic of main girder is optimized and the guide plate is arranged, which have improved wind resistant stability of main girder greatly. According to the statistics of regional vehicle loading and based on the analysis on fatigue life of steel deck surface plate by measures of increasing the thickness of top slab, adding transverse ribs between diaphragms the stress of top slab is reduced thus improving the fatigue life of steel bridge deck. An appropriate solution for pavement is prepared according to the local physical climate unique features and vehicular loading situations. The solution of protective coating against corrosion is determined by overall considering the construction method, coat life and cost. By 3D simulation analysis method the forces on main girder under various cases are analyzed. Those above key technologies are of reference value for designs of similar bridges.
  Authors: Wu, Mingyuan
  Authors: Wu, Mingyuan
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 220
  Paper Number: 13-3558
• Effects of Chevron Alignment Signs on Driver Visual Perception, Manipulating Behavior, and Psychological Reactions
  Abstract: In China, Chevron Alignment signs (a vertical rectangle with a white arrow and border on a blue background) have been widely used on roadway horizontal curves to provide advance warning and positive guidance through curves. Chevron Alignment signs are retroreflective guidance devices installed near roadway edges indicating roadway alignment. But the effects of the Chevron Alignment signs on drivers¡¯ visual perception, manipulating behavior and psychological reactions have rarely been studied. Few guidelines have been established for the size and application of Chevron signs in China. Based on driving simulation experiments, drivers¡¯ eye movement, manipulating behavior and psychological conditions data were simultaneously collected for two scenarios: driving through a horizontal curve with and without Chevron Alignment signs. A comparative analysis was conducted to examine the changes in drivers¡¯ visual perception, manipulating behavior and psychological reactions. The results show that drivers pay more attention to the roadside near Chevrons; they are also more relaxed, tending to drop their speed more when Chevrons are present. This finding indicates that Chevron Alignment signs do provide advance warnings, positive guidance and make drivers tend to drop speed more through curves, improving the safety and uniformity in curve delineation on urban expressway ramps.
  Authors: Wu, Yiping; Zhao, Xiaohua; Rong, Jian; Ma, Jianming
  Authors: Wu, Yiping; Zhao, Xiaohua; Rong, Jian; Ma, Jianming
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 544
  Paper Number: 13-3568
• Pavement Condition States Before and After Treatments
  Abstract: When a pavement section is subjected to preservation or rehabilitation treatments, its surface conditions transfer from one set of condition states before treatment to another set of condition states after treatment. This transformation is a function of the pavement condition states before treatment, the treatment types and timing, the project boundaries, and the quality of construction. For most pavement sections, the before and after treatment surface conditions vary substantially along the section and over time. In this study, which is sponsored by the Federal Highway Administration (FHWA), the distributions of the pavement surface conditions and distress before and after treatment along several flexible pavement projects in the State of Louisiana were analyzed. It is shown that the current practice regarding the selection of pavement treatment type, treatment time, and project boundaries are independent of the pavement surface conditions and distress before treatment.For all pavement projects that received certain treatment types in the past, knowledge of the relationships between the before and the after treatment distributions of the pavement surface conditions and distress is crucial to the establishment of future cost-effective pavement treatment strategy. This paper shows that such relationships can be expressed by the probabilities of transforming the before treatment condition states to the after treatment condition states. These probabilities could be housed in one matrix format called the “Treatment Transition Matrix (T2M)”. For each treatment type, the T2M presents a snap shot of the state-of-the-practice.
  Authors: Baladi, Gilbert Y.; Dean, Christopher M.
  Authors: Baladi, Gilbert Y.; Dean, Christopher M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-3599
• Sprinkle Treatment on Thin Durable Asphalt Overlays
  Abstract: This paper presents techniques to improve asphalt overlays through the use of innovative surfacing technologies with durable aggregates spread on a cost-effective base wearing surface mixture using local aggregates. The sprinkle treatment was previously used in a few states in order to improve skid resistance of pavement surfaces on top of typical asphalt pavements. Over past decades, numerous approaches have been introduced to improve the performance of asphalt pavement. These improvements often add cost because of using high quality aggregates and modified binder. Since sustainable and cost-effective pavements are being emphasized, innovative application of the sprinkle treatment has been considered. A fine dense-graded asphalt wearing surface mixture, developed using the Bailey method, provides a promising aggregate structure that makes it possible to ensure compactibility using relatively thinner asphalt mixture layers. The mix design of the base mix was developed using less expensive local aggregates, and its performance was evaluated and compared with two control mixtures for durability, rut resistance, moisture susceptibility, fracture, and complex modulus in the laboratory. In addition, test pavements of various thicknesses were constructed in northern Illinois during October and November 2010 to evaluate the performance of sprinkle treatment pavements under real traffic loading. On-site performance tests that include noise, friction, rut depth and texture profiles were conducted at four-month intervals following construction. The study concluded that it is feasible to use a cost effective alternative wearing surface that performs well.
  Authors: Son, Songsu; Al-Qadi, Imad L.; Lippert, David Leslie; Zehr, Thomas G.
  Authors: Son, Songsu; Al-Qadi, Imad L.; Lippert, David Leslie; Zehr, Thomas G.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-3612
• Impacts of Continuous Data Collection on Accuracy of Pavement Management Decisions
  Abstract: The current economic climate is forcing reduction in the costs of data collection using sampling. For semi-automated distress data collection techniques, data sampling implies continuous pavement imaging and digitization of the images of sampled pavement segments. Although sampling precipitates immediate reduction in the cost of data collection, its true costs cannot be determined unless the impacts of data sampling on the accuracy and variability of the pavement condition data are analyzed.In this study, sponsored by the Federal Highway Administration (FHWA), continuously collected time series pavement distress data were requested and obtained from the Sates of Colorado, Louisiana, Michigan, and Washington. The transverse and longitudinal cracking data for 109 miles of pavement were used to simulate ten percent sampling and determine the effects of data sampling and sample size on the accuracy of the pavement condition data. For each one mile of pavement, the distress data along the sample were assumed to represent the condition along the entire mile.The paper shows that the accuracy of data sampling is a function of the sample size and the uniformity or variability of the distress data. Furthermore, as time elapses and pavement deteriorates with no applied treatments, variability between continuous and sampled data sets increases substantially. As expected, increasing the sample size reduces the differences between the sampled and continuous data. However, given that some states use ten percent sample size, it is likely that the potential misallocation of pavement treatment funds due to sampling may outweigh the savings incurred by sampling.
  Authors: Baladi, Gilbert Y.; Dean, Christopher M.
  Authors: Baladi, Gilbert Y.; Dean, Christopher M.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 780
  Paper Number: 13-3617
• Development of Time-Efficient Genetic Algorithm Backcalculation Method for Flexible Pavements
  Abstract: Non-destructive testing (NDT) methods, especially Falling Weight Deflection (FWD) test, are invaluable for assessing the structural load capacity of pavements. In order to determine the structural capacity of existing roads, engineers need accurate information on the thickness and elastic modulus of the various layers. Layer moduli and thicknesses are used to calculate load capacities to predict the performance of roads and select appropriate rehabilitation actions. Unfortunately, there is no analytical approach for back-calculation of FWD test output. Most of the existing back-calculation programs model deflection basin by minimizing a function which is related to difference of the calculated and measured deflections. Since the objective function is usually complex and has several minima, traditional calculus-based optimization techniques are often ineffective for obtaining the best fit. This paper, reviews different methods that can be used to back-calculate pavements layer moduli. Since genetic algorithms (GAs) have demonstrated significant potential for solving problems involving multi-modal search spaces, in this study GAs were employed to obtain the best deflection basin fit. Although GAs are strong search engines, they are not time efficient and require a long search time. The objective of this study is mainly to improve the time efficiency of GA-based search engine used for back-calculation. Using a novel method of coding and data structure, authors developed a time efficient back-calculation software, named MBGA: Moduli Back-calculation using Genetic Algorithm. Other issues such as the effect of pavement structure on the optimum value of GA parameters, and the effect of a rigid layer on MBGA convergence were investigated. MBGA performance was evaluated under various conditions for three and four-layer pavement systems. Results demonstrated that the new GA-based search engine not only performed well in finding the global optima, but also reduced the search time significantly. Since MBGA unlike the other GA-based programs requires reasonably short computational time, it can meet the engineering needs for practical use.
  Authors: Motamed, Arash; Tabatabaee, Nader; Motamed, Moggan
  Authors: Motamed, Arash; Tabatabaee, Nader; Motamed, Moggan
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 665
  Paper Number: 13-3637
• Effectiveness Evaluation of Mississippi's Pavement Warranty Program
  Abstract: More and more state highway agencies have adopted pavement warranty programs in their project contracting in order to foster contractor innovation, enhance pavement performance, reduce agency costs, and preserve pavement construction investment. The Mississippi Department of Transportation (MDOT) initiated its pavement warranty program in 2000. This study evaluated the effectiveness of MDOT’s pavement warranty program, using the rutting, cracking, IRI, and other typical surface distress data that were collected and stored in MDOT’s pavement management system database. The distributions of the pavement performance data at different service times were developed for both warranty and non-warranty projects to reveal the pavement performance characteristics under the two contracting methods. Furthermore, pairwise comparison of the distributions of pavement performance data at different service times was conducted to investigate the pavement deterioration patterns over time for both warranty and non-warranty pavements. Finally, two-sample t-tests were performed to compare the performance of warranty versus non-warranty pavements at the same service times. The results of the study showed that the deterioration rate of the warranty pavements was slower than the non-warranty pavements and the performance of the warranty pavements was superior to the non-warranty pavements at the same service times. Based on the statistical analyses, it could be concluded that the pavement warranty program in Mississippi can effectively improve the pavement performance for the state.
  Authors: Qi, Yan; Wang, Feng; El Gendy, Amin; Li, Yibo
  Authors: Qi, Yan; Wang, Feng; El Gendy, Amin; Li, Yibo
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 479
  Paper Number: 13-3644
• Using Structural Equations Modeling to Analyze User Satisfaction in Intermodal Transfer Facilities in Lisbon, Portugal
  Abstract: This research evaluates user satisfaction in intermodal transfer facilities, and the characteristics of these infrastructures that could influence passenger satisfaction, using the Lisbon Metropolitan Area as a case study. For this, a survey in eight major transit interchanges was conducted. Also, an inventory of attributes (e.g. platform identification, litter and/or graffiti, restrooms, seating, lighting, presence of security guards, among others) available in these transit interchanges was made. Using both data sources a structural equations model was built to assess the relations between different specific aspects of reported satisfaction levels. This model included also, variables describing the socioeconomic and behavioral characteristics of the respondents and intermodal transfer facilities attributes. The results obtained suggest that there is a hierarchical structure between different specific aspects of satisfaction and that both transit interchanges attributes and respondent characteristics significantly affect user satisfaction levels. Also it was found that the presence of litter and graffiti’s, as well as the presence of guidance signs influence significantly the levels of satisfaction.
  Authors: de Abreu e Silva, João; Bazrafshan, Hossein
  Authors: de Abreu e Silva, João; Bazrafshan, Hossein
  Year: 2013
  Document Type: Paper
  Subject: Design; Passenger Transportation; Public Transportation; Terminals and Facilities
  Session: 389
  Paper Number: 13-3655
• Development of Field Rut Prediction Models from an Instrumented Test Section on Interstate-35
  Abstract: This paper presents the development of two different field calibrated rut prediction models based on data collected from an instrumented pavement section on I-35 in McClain County, Oklahoma. Two rut prediction models: vertical strain-based (VSB) and shear strain-based (SSB) were developed utilizing four years of pavement and environmental data and from approximately 18.7-million accumulated axles. The VSB model considers vertical strain on the top of the aggregate base layer, while SSB model was based on the shear strain in the Hot Mix Asphalt (HMA) layer. Falling weight deflectometer (FWD) tests were conducted over a wide range of temperature to establish modulus and temperature relationship. WinJULEA, a pavement analysis software, was used to develop correlations between temperature and vertical and shear strains for single and tandem axles. In addition, field rut measurements were conducted periodically using a straight edge-rut gauge combination and a Face Dipstick®. The rut progression graphs show that the test section underwent both primary and secondary rutting. The correlation coefficient (R2 value) for VSB and SSB models were found to be 0.86 and 0.80, respectively. Overall, the VSB model performed better when compared to the SSB model. A systematic methodology to develop these models is presented in the paper. The results from this study are expected to be useful in predicting rut of state highway pavements under similar traffic and environmental conditions. In addition, data collected from this study may be used for local calibration of rut prediction model available in the Mechanistic-Empirical Pavement Design Guide (MEPDG).
  Authors: Hossain, Nur; Solanki, Pranshoo; Zaman, Musharraf; Muraleetharan, Kanthasamy K.; Singh, Dharamveer
  Authors: Hossain, Nur; Solanki, Pranshoo; Zaman, Musharraf; Muraleetharan, Kanthasamy K.; Singh, Dharamveer
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 554
  Paper Number: 13-3656
• Three-Dimensional Finite Element Model for Analysis of Transverse Cracking in Continuously Reinforced Concrete Pavement
  Abstract: In this study, a three dimensional finite element model was developed to investigate crack development and mechanical responses of steel bar and concrete slab of continuously reinforced concrete pavement. An incremental method was adopted to take into account variations of free contraction strains and material properties of concrete in the early stage after casting. A model of mechanical interaction between steel and concrete was developed and values of the parameters were identified by comparing calculated and measured responses. Effects of crack spacing, base course stiffness and depth of steel bar on steel bar and concrete slab stresses and crack width were examined. It was found that strong bonding between steel and concrete leads to higher stresses in steel bar and concrete slab. Short crack spacing reduces tensile stresses in steel bar and concrete slab and crack width. Small peak in tensile stress on the top of slab near crack appears when stiffness of base course is low. The peak of tensile stress might cause “secondary” crack near “primary” crack. Deeper steel bar position leads to wider crack width at the top of slab. Embedding steel bars at a third depth of slab thickness is a reasonable practice to keep crack width tight on the slab surface and prevent water penetration.
  Authors: Nishizawa, Tatsuo
  Authors: Nishizawa, Tatsuo
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 474
  Paper Number: 13-3684
• Flexural Behavior of Hybrid FRP-Ultra-High-Performance Fiber-Reinforced Concrete Composite Beams
  Abstract: This paper presents the development of a new composite beam consisting of a hybrid CFRP/GFRP I-beam and precast Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) slab. Hybrid FRP (HFRP) provides the advantage of high corrosion resistance while UHPFRC has high strength and durability. The combination of these two materials is expected to benefit structures subjected to severe environmental conditions and wherever there is a need for accelerated bridge construction. Three full-scale composite beams with varying UHPFRC slab width were tested under four point flexural loading. Bolt shear connectors with/without epoxy bonding were used in the tested beams. The bolt shear connectors and epoxy were used to resist the horizontal shear flow at the interface between the HFRP I-beam and the UHPFRC slab. The composite action between the HFRP I-beam and UHPFRC slab was investigated. The test results showed that all the composite beams exhibited significant improvements in stiffness and strength properties, above those of simple HFRP I-beam without UHPFRC slab. A fiber model was developed to predict the strength and stiffness of the tested beams and the model accuracy was verified. A fairly good agreement between the experimental and analytical results was found. High tensile strength of the CFRP in the HFRP tensile flange can be effectively utilized and delamination failure of the HFRP compressive flange can be prevented by addition of the UHPFRC slab on the top flange of the HFRP I-beam. The study revealed that HFRP-UHPFRC beams are efficient and can provide a very competitive, cost-effective and sustainable solution to bridge structures.
  Authors: Nguyen, Hai D.; Hiroshi, Mutsuyoshi; Zatar, Wael A.
  Authors: Nguyen, Hai D.; Hiroshi, Mutsuyoshi; Zatar, Wael A.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Materials
  Session: 461
  Paper Number: 13-3699
• Measuring Impact of Digital Information Displays on Speed: Driving Simulator Study
  Abstract: Speeding is a major problem in today’s society and is estimated to contribute to about 30 percent of all fatal crashes. The primary objective of this study is to examine the impact of digital information displays on speeding behavior at 70km/h to 50km/h transition zones. Two real world locations with a high percentage of speeding violations are rebuilt as realistic as possible in a driving simulator. Sixty-six participants completed an 18.9km trip within a randomized between (location: A, B) – within (condition: no display or one of three display messages: smiley, “You are speeding! / Thank you” or “Speed control”) subjects design. The first two messages are social approval/disapproval messages, while the “Speed control” message confronts drivers with the (financial) risk of receiving a fine (i.e. a deterring message).Results show a significant speed reduction effect of the three digital messages compared to the control condition from 50m before the digital display until 100m after the digital display. The largest mean deceleration was also located between 50m and 25m before the digital display. The speed reduction effect of the “You are speeding / Thank you” and “Speed control” messages lasted until 175m after the digital display. Overall, the “Speed control” condition was found to be most effective (both in terms of size as in terms of distance) in reducing speed. However, 500 meters after the devices no significant speed reduction was measured anymore. These results imply that a deterring message is more effective in reducing speed compared to the approving/disapproving messages.
  Authors: Ariën, Caroline; Cornu, Joris; Brijs, Kris; Brijs, Tom; Vanroelen, Giovanni; Jongen, Ellen M.M.; Daniels, Stijn; Wets, Geert
  Authors: Ariën, Caroline; Cornu, Joris; Brijs, Kris; Brijs, Tom; Vanroelen, Giovanni; Jongen, Ellen M.M.; Daniels, Stijn; Wets, Geert
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 544
  Paper Number: 13-3701
• Design Model for Confinement Reinforcement in Pretensioned Concrete I-girders
  Abstract: The 2007 AASHTO LRFD Bridge Design Specifications contain prescriptive requirements for the quantity and placement of confinement reinforcement located in the bottom bulb of pretensioned concrete I-girders. This paper proposes a model that can be used to design confinement reinforcement as an alternative to the prescriptive requirements of AASHTO. The model considers a wide range of conditions and variations, yet is intended to be practical enough for use by bridge design engineers. Variables in the design model include: flange and bearing geometry, strand size and placement, effective prestress force, concrete and steel material properties, and the effects of steel bearing plates. The model is based on strut-and-tie and shear-friction concepts and considers the lateral-splitting failure mode. Derivation of the model is presented, and the model is compared to experimental results from the published literature.
  Authors: Ross, Brandon E.; Hamilton, H. R.; Consolazio, Gary
  Authors: Ross, Brandon E.; Hamilton, H. R.; Consolazio, Gary
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 628
  Paper Number: 13-3724
• Recycling of Urban Road Using Foam Bitumen: Indian Experience
  Abstract: Recycling of pavements is a relatively new technique in India and gaining popularity in recent times due to several merits over conventional pavement rehabilitation techniques. The first recycling work of flexible pavements was undertaken nearly a decade ago and since then milling and recycling of pavements has been adopted in some parts of urban and high volume roads in India. However there have been no research studies reported on these works. In recent times, foam bitumen recycled pavement work was undertaken on some urban roads of Kolkata city in India, Detailed investigation on milling and foam bitumen recycling work of these pavements was performed and presented in this paper. Laboratory investigation on milled and recycled material, field evaluation using Falling weight deflectometer (FWD) before and after rehabilitation was carried out.. Results indicate that the foam bitumen recycling is a very promising alternative to rehabilitate the pavements and to address the concern of conservation of energy and natural resources.
  Authors: Muppi Reddy, Amaranath Reddy; Reddy, K. Sudhakar; Pandey, Braj Bushan
  Authors: Muppi Reddy, Amaranath Reddy; Reddy, K. Sudhakar; Pandey, Braj Bushan
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 555
  Paper Number: 13-3740
• Current Practices for Prioritization of Rehabilitation and Preventive Maintenance of Pavement Projects in Texas
  Abstract: With finite resources and an extensive road network to maintain, state agencies must make optimal and cost-effective decisions to prioritize roadways to receive rehabilitation (RH) and preventive maintenance (PM) treatments. Prioritization methods implemented by state agencies range from a simple ranking of projects based on judgment to comprehensive optimization by mathematical programming models. The Texas Department of Transportation (TxDOT) districts make RH and PM decisions based on data extracted from the Pavement Management Information System (PMIS). Each district uses a combination of approaches that rely significantly on judgment for identifying RH and PM projects. There is a pressing need to develop a simple, comprehensive prioritization method that reflects state-wide experience, while it is easy to implement using PMIS data. A state-wide survey was developed to obtain the various methods the districts use to make these decisions. The responses obtained suggested that the PMIS data combined with visual inspection are the main tools use to prioritize projects. A computer tool was developed utilizing the information obtained from the survey data. It relies on a prioritization index based on the weights assigned to various distresses, as well as other factors such as traffic levels and structural condition. This computer tool was successfully verified by comparing its output to actual decisions made by TxDOT district personnel.
  Authors: Dessouky, Samer H; Papagiannakis, A. Thomas; Krugler, Paul E.; Freeman, Thomas John
  Authors: Dessouky, Samer H; Papagiannakis, A. Thomas; Krugler, Paul E.; Freeman, Thomas John
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 479
  Paper Number: 13-3751
• Improvement in Pedestrian Crossing Safety at Continuous-Flow Intersections
  Abstract: Traditional four-phase, four-legged intersections often operate inefficiently, severely restricting the available throughput and resulting in large delays. These configurations are limited by their traditional geometric design, and altering the geometry of the entire intersection can significantly increase capacity. Continuous flow intersections utilize an unconventional lane arrangement to maximize the vehicular throughput. This arrangement involves displacing left turn lanes across opposing through traffic before the main intersection is reached. Such an alteration allows left and through vehicles to proceed simultaneously, and consequently, both the intersection capacity and delay are improved. Numerous studies have validated its operational improvements, but pedestrian exposure to passing vehicles is high due to the unconventional configuration. In addition, both pedestrian crossing time and distance traveled are longer than desired. In this paper, the authors proposed and tested an enhanced continuous flow intersection configuration to improve the pedestrian experience. Heightened intersection delay is often a result of pedestrian crossing activity, for which a flexible signal control program has been developed specifically for this intersection to reduce vehicle delay while prioritizing pedestrian safety. The signal control procedure dynamically chooses the appropriate phase and green time combination to minimize delay by considering pedestrian wait time and existing queue size. A simulation analysis was performed using this advanced control methodology, and the results of this study have strongly shown how the implementation can enhance the pedestrian crossing experience while minimizing vehicle delay at a continuous flow intersection.
  Authors: Coates, Angela; Yi, Ping
  Authors: Coates, Angela; Yi, Ping
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-4103
• Laboratory and Field Evaluation of Cold-in-Place RAP Recycling
  Abstract: Cold in-place recycling (CIR) is a viable pavement rehabilitation technique that recycles 100% of the reclaimed asphalt pavement (RAP) in situ, without heat. Six test sections were constructed on a heavy traffic road in the south of Brazil using CIR with cement and cationic slow set polymer modified emulsion (CSS-1P). Different thickness of the recycled layer (80mm, 110mm, and 150mm) and two types of asphalt surface layers (HMA and Microsurfacing) were investigated. The RAP was sampled during the recycling operations and brought to the laboratory for its characterization and further mechanical tests evaluation (tensile strength, moisture sensitivity, and triaxial resilient modulus). Field samples were obtained from the test sections to evaluate the performance of recycled mixture. They were tested for rutting resistance (LCPC wheel tracking test) and indirect tensile resilient modulus. Structural evaluation of the test sections were performed through the FWD in different seasons of the year. It was observe a decrease in the modulus of the recycled layers during the rainy season, in comparison with the dry season results. The laboratory tests also indicated a moderate moisture sensitivity material. The backcalculated resilient moduli of the CIR layer presented the same order of magnitude of the moduli obtained in the laboratory tests. The CIR presented reduced permanent deformation in the laboratory and low rutting in the field after two years of the rehabilitation.
  Authors: Marcandali da Silva, Amanda Helena; Vasconcelos, Kamilla L.; Aranha, Ana Luisa; Bernucci, Liedi Bariani; Chaves, José Mario
  Authors: Marcandali da Silva, Amanda Helena; Vasconcelos, Kamilla L.; Aranha, Ana Luisa; Bernucci, Liedi Bariani; Chaves, José Mario
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 555
  Paper Number: 13-4178
• Three-Dimensional Parametric Data Exchange for Curved Steel Bridges
  Abstract: Improved software interoperability is key to more fully realizing the potential benefits of integrated and accelerated project delivery in a way that somehow also ensures product quality. The increasing appeal of 3D BIM (Building Information Modeling) notions applied to bridges (BrIM – Bridge Information Modeling) motivates the need for principled prescriptions of associated electronic data exchanges among various project stakeholders and the various software applications they use. Such data exchanges need to be sufficiently precise to facilitate detailing for fabrication and construction while also being sufficiently concise to facilitate parametric modeling and thereby avoid needless data duplication. The highway geometry to which bridges must conform distinguishes BrIM from the building column-grid orientation of BIM at the outset of the bridge lifecycle. In contrast to the overdefined highway geometry contained in the LandXML data exchange standard, this paper defines, presents, illustrates, and recommends the use of a “3D control curve” as the basis for parametric data exchange suitable through the lifecycle of steel I-girder bridges on (straight and) curved alignments. This 3D control curve combines in a single curve the traditional horizontal control line and profile grade line that bridge structural engineers receive from highway designers in order to define bridge geometry. Data exchanges associated with 3 distinct stages in the steel bridge lifecycle are defined and illustrated herein: analysis and design, detailing for fabrication, and erection/construction. It is shown that “3D control curve” based data exchange suffices for the data integrity required through the steel bridge life-cycle.
  Authors: Karaman, S. Gokhan; Chen, Stuart S.; Ratnagaran, Benny J.
  Authors: Karaman, S. Gokhan; Chen, Stuart S.; Ratnagaran, Benny J.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 317
  Paper Number: 13-4186
• Hazardous Bicycle Maneuvers at Single-Lane Roundabouts in Massachusetts: A Conflict and Events Study
  Abstract: Roundabouts have been known to relieve congestion, reduce travel times, and decrease accident rates. Studies indicate that despite reducing the total crash rate, roundabouts show a significant increase in the proportion of crashes that involve a cyclist. These crashes are primarily due to cyclists who create a bicycle lane through the roundabout. The purpose of this study is to determine if cyclist safety should be of particular concern in roundabouts in Massachusetts, specifically whether or not cyclists and/or vehicles are performing maneuvers outlined in previous studies to be major contributors for cyclist-based crashes. A custom conflict/event and compliance study was designed. Preliminary studies were performed at a roundabout located at the University of Massachusetts, Amherst. Subsequent studies were performed at various roundabout locations throughout Massachusetts. This study recorded all bicycle movements and any observed bicycle/vehicle interactions, tracking specific maneuvers that could create a hazardous or unsafe situation. The number of bicycles that performed unsafe maneuvers was compared to the total number of bicycles observed traversing the roundabout.This study confirms that some cyclists who use the roundabout at the University of Massachusetts Amherst operate in an unsafe manner or in a way defined to be a leading cause of accidents involving a bicycle in a roundabout (32% of all observed cyclists). Similar results were found at other roundabouts throughout Massachusetts (33% of all observed cyclists). Possible solutions were postulated.
  Authors: Berthaume, Andrew Leo; Knodler, Michael A.
  Authors: Berthaume, Andrew Leo; Knodler, Michael A.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-4216
• Real-Time Monitoring of Bridge Scour with Magnetic Field Strength Measurement
  Abstract: Scour was responsible for most of the U.S. bridges that collapsed during the past 40 years. The maximum scour depth is the most critical parameter in bridge design and maintenance. Due to scouring and refilling of river-bed deposits, existing technologies face a challenge in measuring the maximum scour depth during a strong flood. In this study, a new methodology is proposed to integrate passive sensors into the process of bridge scour for real time monitoring during a flood event. Towards this end, a permanent magnet can be embedded in a natural rock to function as a passive sensor, which is herein referred to as a smart rock. The smart rock can be designed such that, once deployed around a bridge pier, it continually falls into the bottom of a gradually growing scour hole and thus registers the maximum scour depth with magnetic field strength measurements. Specifically, this paper discusses the societal needs for bridge scour monitoring, demonstrates the concept and the working principle of smart rocks, and summarizes the findings from various calibration and validation tests recently conducted at Missouri University of Science and Technology and at Turner-Fairbank Highway Research Center. It was demonstrated that the magnetic field strength can be strongly correlated with the increase of scour depth over time. Properly designed smart rocks fell into and remained at the bottom of a scour hole, providing critical data in the process of scour development.
  Authors: Chen, Genda; Schafer, Brandon; Lin, Zhibin; Huang, Ying; Suaznabar, Oscar; Shen, Jerry
  Authors: Chen, Genda; Schafer, Brandon; Lin, Zhibin; Huang, Ying; Suaznabar, Oscar; Shen, Jerry
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Hydraulics and Hydrology; Pavements
  Session: 728
  Paper Number: 13-4235
• Influence of Temperature on Tire-Pavement Friction-1: Laboratory Tests and Finite Element Modeling
  Abstract: The temperature development in tire-pavement contact region results in a complex relationship between temperature and friction. Tire rubber hysteresis on a road is considered to play an important role in countering skidding for a vehicle travelling at high speed. Past studies showed that the contribution from hysteresis component in comparison to adhesion has a larger influence on friction measurements. Variation in the tire temperature may result in unreliable interpretation of friction data particularly with continuous friction measuring equipment. Ever increasing need of driver safety poses challenges to the highway authorities to evaluate pavement conditions even more precisely. The present paper aims to develop a finite element model capable of assessing the effect of temperature on hysteric friction over a scan of real textured pavement surface. A dynamic analysis of tire rolling at any defined slip ratio, over a textured pavement surface and subsequent development of tire temperature would require a large computational time even for a powerful computer. Thus a new methodology using sequential analysis of static (for smooth surface) to dynamic (for slipping over rough surface) followed by a staggered temperature-analysis is developed. In this methodology, using the laboratory test data, a thermo-mechanical coupling model was developed to calculate the progressive development of temperature and its effect on the hysteretic friction. It was observed that the hysteretic friction of tire rubber decreases with increase in temperature.
  Authors: Srirangam, Santosh Kumar; Anupam, Kumar; Scarpas, Athanasios; Kösters, Anton
  Authors: Srirangam, Santosh Kumar; Anupam, Kumar; Scarpas, Athanasios; Kösters, Anton
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 552
  Paper Number: 13-4260
• Assessment of Background Complexity of Overhead Guide Signs from Nighttime Digital Images of Roadway Scenes by Image Processing
  Abstract: Researchers have developed a systematic method to assess the background complexity of overhead guide and street name signs under nighttime driving conditions using image processing techniques. These techniques are used to extract image properties such as entropy, contrast, energy, homogeneity, number of saturation pixels, edge ratio, and number of objects, all of which are considered as potential factors for evaluating the background complexity. The researchers combined these factors with image survey ratings by human participants to develop a multivariate linear regression model that could be used by practitioners to evaluate background complexity of overhead guide and street name signs under nighttime conditions. Bootstrapping, a resampling method, was employed to improve the performance of proposed model due to the small samples of the data sets. The empirical results demonstrate that the proposed model has a good performance in the analysis of background complexity of traffic signs with high consistency with ratings from survey participants. It is believed that this model could be used by practitioners to identify potential overhead guide and street name signs that have highly complex backgrounds and may require sign lighting, supplemental signs, and/or relocation to minimize driver difficulty in detecting and obtaining information from the signs.
  Authors: Ge, Hancheng; Zhang, Yunlong; Miles, Jeffrey David; Carlson, Paul J.
  Authors: Ge, Hancheng; Zhang, Yunlong; Miles, Jeffrey David; Carlson, Paul J.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 550
  Paper Number: 13-4305
• Associations Between Road Network Structure and Pedestrian-Bicyclist Accidents
  Abstract: It is widely known that the road network layout can impact the non-motorized users’ traffic safety by changing the non-motorized traffic volume and road users’ behavior. Different road network patterns lead to different traffic safety levels for non-auto users and a single pattern can even have both the safe and unsafe features at the same time. By knowing what features can lead to safer traffic environment, existing road networks can be improved and new network patterns can be produced by combining all safe features from different patterns. Therefore, the associations between road network structure and pedestrian-bicyclist crashes are analyzed in this paper to determine how the structural features of a road network affect non-motorist safety. Three structural measures including average geodesic distance, network betweenness centrality, and overall clustering coefficient are calculated based on the road networks of 321 census tracts in Alameda County, California. Then the three measures together with other factors like traffic behavior, land use, transportation facility, and demographic features are employed separately in a spatial statistical model called geographically weighted regression. Conclusions are: if a network is more highly centered on major roads, there will be fewer non-motorist crashes; the network which has more average number of intersections between each pair of roads tends to have fewer accidents for pedestrians and bicyclists; and, the more a network is clustered into several sub-core networks, the lower the non-motorist crash count will be.
  Authors: Zhang, Yuanyuan; Bigham, John M.; Li, Zhibin; Ragland, David R.; Chen, Xiaohong
  Authors: Zhang, Yuanyuan; Bigham, John M.; Li, Zhibin; Ragland, David R.; Chen, Xiaohong
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-4316
• Experimental Analysis and Methodological Approach by Microsimulation of Crossing-Speed Distribution on Small- and Large-Diameter Roundabouts
  Abstract: In literature many studies have shown how speed distribution in roundabouts, together with other parameters (entering flow, circulating flow, entry curvature, entry path radius, entry width, approach width, ratio of inscribed circle diameter/central island diameter, angle to next leg, etc.), can be used as a measure of safety performance for these kind of intersections. The wide use of several micro-simulation models for a preventive analysis of roundabouts performance (capacity, delays, safety, etc.) emphasizes the need for a deeper study of the most sensitive parameters for a better fitting between simulated and observed traffic conditions.This paper focuses on an experimental analysis of the through movement in two roundabouts characterized by different values of the inscribed circle diameter (D1˜1/2•D2) and located close together in the same road-straight in the University Campus of Arcavacata, Italy. The main aim of the research is the suggestion of a methodological approach to the simulation process of the through movement by the use of VISSIM® micro-simulation software for the above mentioned roundabouts.Results concern the following issues: (i) coherence validation of experimental data regarding speed distributions along the trough movement as a function of roundabout radius; (ii) methodological and procedural issues related to the implementation of simulation parameters in VISSIM, particularly referring to speed distributions along the crossing movement, in order to better understand the effects of the change of roundabouts geometric features on simulation results.
  Authors: Vaiana, Rosolino; Gallelli, Vincenzo; Iuele, Teresa
  Authors: Vaiana, Rosolino; Gallelli, Vincenzo; Iuele, Teresa
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-3787
• Exploratory Evaluation of the Impact of Spectral Power Distributions on Driver Performance
  Abstract: The purpose of this project was to provide an initial investigation into the effects of different light source spectral distributions on detection and color recognition of roadway objects and pedestrians. This project included an investigation of both the light source spectrum from the overhead lighting spectrums as well as that from the vehicle headlamp. In order to investigate this, high-pressure sodium (HPS) and light emitting diode (LED) overhead lighting systems were considered, as well as headlamps filtered to resemble LED and the amber HPS sources. The detection and color recognition of pedestrians and wooden targets were evaluated by driver participants under controlled combinations of overhead and headlamp lighting using a similar protocol to studies that have already been performed at the Virginia Tech Transportation Institute.The main conclusions from this investigation indicate that: 1) There is not a significant difference between the spectrum of the vehicle headlamps selected in terms of the detection of pedestrians and targets located immediately alongside the roadway. 2) Overhead lighting is a significant factor in the detection and color recognition of pedestrian clothing, but results indicate it’s the intensity not necessarily the color of the lighting that makes it a significant factor. 3) Spectral components of overhead lighting and headlamp lighting may play a much more significant role in pedestrians located peripherally, rather than strictly along the roadway.
  Authors: Gibbons, Ronald B.; Meyer, Jason
  Authors: Gibbons, Ronald B.; Meyer, Jason
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-3803
• Characterization of Opposite-Direction Lane Departure Crashes in the United States
  Abstract: Opposite direction crashes have the potential to be extremely severe because opposing vehicles often have high relative speeds. The objective of this study was to characterize opposite direction crashes in overall frequency as well as fatal and serious injury crash frequency. The results of this study can be used to guide future research and investment in infrastructure opposite direction countermeasures, such as centerline rumble strips. We used the 2010 National Automotive Sampling System (NASS) General Estimates System (GES), the 2010 Fatality Analysis Reporting System (FARS), and 2006-2010 NASS Crashworthiness Data System (CDS). We found that the most common opposite direction crash scenario was a driver departing over the center line or road edge to the left, which accounted for only 5% of non-junction vehicle-to-vehicle crashes but 48% of fatal and 44% of serious injury crashes of the same type. Of these cross over to left crashes, 72% of fatal crashes occurred on rural undivided two-lane roads accounting for 1,618 fatal crashes in 2010. In cross over to left crashes on rural two-lane roads, the driver was going straight or negotiating a curve in 87% to 94% of crashes. The driver was overtaking another vehicle in only 6% of fatal and 2% of serious injury crashes. Crashes occurred on both curves and straight segments. Those that occurred on curves were to the outside of the curve more often than the inside of the curve. This research suggests that opposite direction countermeasures should focus on rural two-lane roads.
  Authors: Kusano, Kristofer D; Gabler, Hampton Clay
  Authors: Kusano, Kristofer D; Gabler, Hampton Clay
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 631
  Paper Number: 13-3805
• Use of Monte Carlo Filtering Method for Regional Sensitivity Analysis of DARWin-ME
  Abstract: Since AASHTO released the Mechanistic-Empirical Pavement Design Guide (MEPDG) for public review in 2004, many highway research agencies have performed sensitivity analyses using the prototype MEPDG design software. The information provided by the sensitivity analysis is essential for design engineers to better understand the MEPDG design model and to identify important input parameters for pavement design. In the past, both local and global sensitivity analyses have been carried out. Meanwhile, different sensitivity indices have been proposed for ranking the importance of the input parameters. However, both local and global sensitivity analyses have their limitations. In this paper, a regional sensitivity analysis method, Monte Carlo filtering (MCF), is presented. The MCF method maintains many advantages of the global sensitivity analysis, while focusing on the regional sensitivity of the MEPDG model near the design criteria rather than the entire problem domain. It was shown the information obtained from the MCF method is more helpful and accurate in guiding design engineers in pavement design practices. To demonstrate the methodology, a typical three-layer flexible pavement structure was used as an example. A detailed procedure to generate Monte Carlo runs using the new DARWin-ME software was provided. Based on the example, the strengths, practical issues, and applications of the MCF method are also discussed.
  Authors: Yang, Xiaoming; Wu, Zhong
  Authors: Yang, Xiaoming; Wu, Zhong
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 239
  Paper Number: 13-3842
• Calibration of Traffic Distributions and Model Coefficients Within MEPDG for Local Energy-Affected Roads in Wyoming
  Abstract: The Mechanistic-Empirical Pavement Design guide was developed in 2004 under NCHRP Project 1-37B. Since this time, considerable efforts to calibrate the program and its performance prediction models for local conditions have taken place in multiple states attempting to implement the program. Currently, Wyoming DOT is in the process of implementing the MEPDG on the interstate and the state highway systems. In order to compliment that effort, this study attempted to develop a set of calibration coefficients and localized inputs that can be used on local paved roads. Wyoming is an energy rich state and has seen an increase in the amount of heavy truck traffic that its roadways encounter, thus requiring calibrated inputs for the MEPDG. Predicted distresses using the MEPDG were largely different from measured distresses on local paved roadways included in the study, particularly alligator cracking, rutting, transverse cracking, and longitudinal cracking. These distresses were measured on the local paved roads using Pathway Services Inc. and the surface imaging that it provided. Inputs for trial runs using the MEPDG were determined through work with local county road maintenance superintendents as well as previous research regarding climatic data in Wyoming. Localized traffic inputs were developed using Weigh-In Motion (WIM) data collected on non-interstate roadways across Wyoming. Once a significant error was found between predicted and measured distresses, calibration coefficients for alligator cracking, rutting, and longitudinal cracking were altered to reduce bias. The final calibration coefficients settled on in this study reduced the error between predicted measured distresses by nearly one hundred percent for the three calibrated models. The process followed in this study can be utilized by other local governments around the country to help them implement the MEPDG.
  Authors: Kasperick, Taylor; Ksaibati, Khaled
  Authors: Kasperick, Taylor; Ksaibati, Khaled
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 242
  Paper Number: 13-3866
• Flow Characteristics of Permeable Pavements by Water Demand and Supply
  Abstract: Permeable pavement is one of the widely used methods to recover the city¡¯s water circulation. The advantages of using permeable pavement is storage of rainwater, reduction of runoff, out-flow delay, and decrement of peak out-flow. Most of the cases out-flow characteristics of different types of permeable pavements were explained focus on runoff coefficient or the relationship between runoff and infiltration rate. With convenient theories which can explain out-flow characteristics and compare different pavement system considering water balance have been insufficient. In this study, an empirical model cumulative water flow versus time concept, is suggested to explain characteristics of out-flow of permeable pavement. This model is suggested to define and explain the variable by accumulating runoff at surface and outflow at subsurface over time that relates to accumulated rainfall. Through this model advantages of different permeable pavement can be compared and explained through rainfall simulation experiment.
  Authors: Cho, Yoon-Ho; Lin, Wuguang; Park, Dae-Geun
  Authors: Cho, Yoon-Ho; Lin, Wuguang; Park, Dae-Geun
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Hydraulics and Hydrology; Pavements
  Session: 728
  Paper Number: 13-3867
• Infrared Thermography-Based Inspection Technique for Void Detection in Bridge Stay-Cables
  Abstract: Cable-stayed bridges are being constructed more frequently due to their architectural appeal, ease of construction, and lower cost and environmental footprint in comparison to other bridge types. On some more recent bridges of that type built in the past 10-20 years, the stay-cables are comprised of greased-and-sheathed, stranded steel wires enclosed in high density polyethylene (HDPE) pipes with the interstices filled with a cementatious grout. This design is susceptible to voids in the grout, which can possibly promote cracking in the HDPE piping and reduce the ability of the corrosion protection to safeguard the wires. Several non-destructive techniques have been used to detect defects (voids) in stay cables. In this work, voids in stay cables are studied using passive infrared thermography during solar irradiation over days from sunrise to sunset. Effects of stay cable material properties, time of the day, solar orientation and void sizes on the capacity of passive infrared thermography to detect defects were studied using a mockup cable constructed with known void sizes and locations. Field testing of the thermographic method was also performed on the US 231 William Natcher Bridge in western Kentucky to validate the mockup results. Grout voids in the bridge stay cables were successfully detected, the detectability of which was found to be dependent on the cable orientation relative to the solar irradiation and the angle of the cable relative to the ground. The thermographic void findings correlated well with other nondestructive methods (GPR and sounding).
  Authors: Salaimeh, Ahmad
  Authors: Salaimeh, Ahmad
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 269
  Paper Number: 13-3912
• Thickness Measurements of Structural Concrete Members with Compact Dimensions Using Ultrasonic Pulse-Echo and Impact-Echo
  Abstract: Thickness measurements are one of the most common applications for acoustic non-destructive testing (NDT) methods for concrete components such as ultrasonic pulse echo and impact-echo. They become relevant whenever components are accessible from only one side and, for example, the design thickness needs to be verified or the geometry of a structure needs to be assessed.While such measurements are relatively easy to conduct on test objects with simple geometries and wide dimensions, they become challenging when the geometry of the test object is more complex or when the dimensions of the test object are rather compact. In this study, measurements have been performed on two test blocks with different geometries. Block A is a solid slab-like block of mostly constant thickness. Block B consists of areas of different thickness. All measurements are conducted using an automated test frame, thus providing dense scan grids and therefore good statistical significance. Two- as well as three-dimensional imaging techniques are applied to the data.Within the thickness range investigated here (169 to 510 mm), ultrasonic pulse-echo has proven to be generally robust even on block B with a rather complex geometry.While impact-echo provides satisfying results on the rather simple slab-like block A, it is severely affected by geometrical effects when measurements are being conducted on a test block B.
  Authors: Algernon, Daniel; Hiltunen, Dennis R.; Ferraro, Christopher C.; Ishee, Charles A.
  Authors: Algernon, Daniel; Hiltunen, Dennis R.; Ferraro, Christopher C.; Ishee, Charles A.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 269
  Paper Number: 13-3913
• Comparison of Material Behavior of Steel and Synthetic Fibers in Dry Cast Application
  Abstract: This study presents the material behavior results of steel and synthetic fiber reinforced concrete. ASTM C1609 flexural beam test and ASTM C39 compressive strength cylinder tests were completed for various fiber dosages of each synthetic and steel fiber. Synthetic and steel fiber dosages ranged from 4 lbs/yd3 to 18 lbs/yd3 and 22 lbs/yd3 to 88 lbs/yd3, respectively. From these tests, material properties were found including; compressive strength, first-peak load, peak load, Modulus of Rupture and specimen toughness. Load- deformation plots were completed for each beam to show the fiber behavior and strengthening after the initial crack.
  Authors: Abolmaali, Ali
  Authors: Abolmaali, Ali
  Year: 2013
  Document Type: Paper
  Subject: Design; Geotechnology; Pipelines
  Session: 249
  Paper Number: 13-3925
• On Accommodating Spatial Dependence in Bicycle and Pedestrian Injury Counts by Severity Level
  Abstract: This paper proposes a new spatial multivariate count model to jointly analyze the traffic crash-related counts of pedestrians and bicyclists by injury severity. The modeling framework is applied to predict injury counts at a Census tract level, based on crash data from Manhattan, New York. The results highlight the need to use a multivariate modeling system for the analysis of injury counts by road-user type and injury severity level, while also accommodating spatial dependence effects in injury counts.
  Authors: Narayanamoorthy, Sriram; Paleti, Rajesh; Bhat, Chandra R.
  Authors: Narayanamoorthy, Sriram; Paleti, Rajesh; Bhat, Chandra R.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-3967
• Enhanced Crack Segmentation Algorithm Using Three-Dimensional Pavement Data
  Abstract: Automatic pavement crack segmentation has gained attention among researchers and transportation agencies over the past two decades. However, most existing algorithms using 2-D pavement intensity images cannot provide satisfactory performance. With the advance of sensing technology, 3-D line laser pavement imaging systems have become available. The objective of this paper is to propose an enhanced dynamic optimization based algorithm utilizing the advantages of 3-D pavement data to improve crack segmentation. The proposed algorithm consists of three major stages. First, a two-step Gaussian filter is applied to remove outliers from the collected laser data and rectify the profile in order to reduce the influence of cross-slope and ruts on crack segmentation. Then, a rough crack segmentation stage is conducted to adaptively identify the crack regions of interest. Finally, a bounding box and major orientation for each valid crack region of interest will provide searching space and direction for the precise crack segmentation using the dynamic optimization based algorithm. Experimental tests are conducted using actual pavement data collected near Savannah, Georgia. The four most common types of pavement cracking (longitudinal, transverse, block, and alligator cracking) are tested, and the performance between original dynamic optimization algorithm and the proposed algorithm is compared. Experimental results show that the proposed algorithm only take about 1/4 of the average computation time of the original algorithm. Also, the accuracy of crack segmentation has been improved, since the proposed algorithm removes the unnecessary false positives and better handles cracks in multiple directions. Finally, conclusions are made and recommendations for future research are discussed.
  Authors: Jiang, Chenglong; Tsai, Yichang (James)
  Authors: Jiang, Chenglong; Tsai, Yichang (James)
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 475
  Paper Number: 13-4021
• Investigation into Top-Down Cracking of Asphalt Pavements in North Carolina
  Abstract: Top-down cracking has become a commonly reported cracking mechanism in asphalt pavements worldwide. In top-down cracking a crack initiates at the surface of an asphalt concrete pavement and propagates to the bottom of the asphalt pavement layer. Because the location and governing state of stress for top-down cracking are different than for bottom-up cracking, pavement cracking performance analysis needs to be robust enough to account for the complex mechanisms that are involved in top-down cracking. This study applies the viscoelastic continuum damage finite element model to the evaluation of two pavement sections in North Carolina where top-down cracking has been identified. Small specimen geometries are used to perform simplified viscoelastic continuum damage (S-VECD) testing on individual asphalt layers obtained from field cores. The S-VECD model and the Fourier finite element program are used together (as the VECD-FFE model) for pavement cracking performance simulations and employ the structure and layer material properties obtained from the two study pavements. The simulation results clearly support the propensity of these pavements to exhibit top-down cracking. In addition to this laboratory testing and analysis, the deflection-based method suggested by Uhlmeyer et al. is applied to the data obtained from pavement sections with known crack initiation locations in order to investigate the method¡¯s validity. The Uhlmeyer method uses the AREA parameter that is determined from falling weight deflectometer deflections, and pavement thicknesses. The analysis results show a clear difference in the AREA versus pavement thickness relationship between the pavement sections with top-down cracking and those with full-depth cracking.
  Authors: Park, Hong Joon; Kim, Y. Richard
  Authors: Park, Hong Joon; Kim, Y. Richard
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 377
  Paper Number: 13-4141
• Evaluation of Community Café's Utility for Public Transportation Use in a Local Community in Japan
  Abstract: Demographic aging and depopulation are forcing local communities in Japan to confront the dilemma of maintaining public transportation services while reducing public transport costs. As a solution, this study discusses the usefulness of a community café (a non-profit-managed public space for eating, drinking and deepening personal interactions) as a bus waiting place. The idea is that passengers can wait comfortably for a bus at a community café even when financial constraints have caused the waiting time to increase as a result of reductions in transportation service frequency. To analyze the relationship between passenger satisfaction with bus transportation when a community café is used as a bus waiting place, a multiattribute utility function (MUF) and orthogonal arrays were used. A questionnaire survey to collect data for analysis was conducted in Atsuma Town, Southern Hokkaido. The bus transport attributes to which MUF was applied in order to evaluate the passenger satisfaction included waiting time, bus fare, and type of waiting place. The analysis shows that the utility function scores for factor combinations such as community café as a bus waiting place and either longer waiting time, or higher bus fare are higher than those for the combinations of canopied shelter with seats and either shorter waiting time or lower bus fare.Such results indicate that using a community café as a bus waiting place may be able to make up for reductions in public bus transport services due to financial constraints.
  Authors: Kishi, Kunihiro
  Authors: Kishi, Kunihiro
  Year: 2013
  Document Type: Paper
  Subject: Design; Passenger Transportation; Public Transportation; Terminals and Facilities
  Session: 389
  Paper Number: 13-4157
• Dynamic Behavior of Ribbon Floating Bridges: Analytical and Experimental Studies
  Abstract: Floating bridges are economical means for crossing water bodies, especially in times of emergencies and war. Ribbon pontoon floating bridges are a special type of floating bridge designed, built and stocked by the military and emergency management organizations and deployed in times of need. They are light-weight, fast to erect, and use the buoyancy of water to aid in supporting the self-weight and traffic loads imposed on the bridge.With increasing vehicular weights and need for fast traversing times, it is necessary to develop analytical tools capable of designing and analyzing floating bridges. This is ideal for optimizing the vehicle weights and spacing to achieve greater economic efficiency.This paper presents an analytical and experimental research program designed to study the dynamic behavior of ribbon pontoon floating bridges under two-axle vehicular loading. The developed analytical method yielded maximum bridge displacements comparable to the experimental results. In most cases, the analytical results were higher than experimental, providing a level of conservatism for design. The midspan displacements were accurately predicted as the vehicle traversed the floating bridge. However, at higher vehicle weights the analytical model failed to accurately predict midspan displacement at axle locations beyond midspan.
  Authors: Viecili, Giannin Marie; Braimah, Abass; Abd El Halim, Halim Omar; El-Desouky, Osama Ibrahim
  Authors: Viecili, Giannin Marie; Braimah, Abass; Abd El Halim, Halim Omar; El-Desouky, Osama Ibrahim
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 317
  Paper Number: 13-4341
• Mechanistic-Empirical Pavement Design Guide Calibration for Pavement Rehabilitation in Oregon
  Abstract: The performance prediction models within the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) were calibrated primarily using design inputs and performance data largely from the national Long-Term Pavement Performance (LTPP) program. Before implementing the MEPDG at the state level, performance (distress) prediction models warrant detailed validation and calibration because of potential differences between national and local conditions. The Oregon Department of Transportation (ODOT) is in the process of implementing the new MEPDG for new pavement sections. However, the vast majority of pavement work conducted by ODOT involves rehabilitation of existing pavements. Hot mix asphalt concrete (AC) overlays are the preferred rehabilitation treatment for both flexible and rigid pavements in Oregon. However, like new work sections, AC overlays are also susceptible to fatigue cracking (alligator cracking and longitudinal cracking), rutting, and thermal cracking. Additional work is therefore needed to calibrate the design process for rehabilitation of existing pavement structures. A detailed comparison of predictive and measured distresses was made using recently MEPDG released software Darwin M-E (version 1.1). It was found that Darwin M-E predictive distresses did not accurately reflect measured distresses, calling for a local calibration of performance prediction models is warranted. While the local calibration of rutting and thermal cracking prediction models is currently underway, alligator (bottom-up) cracking and longitudinal (top-down) cracking models were calibrated. The Microsoft Excel Solver was employed to optimize the calibration coefficients by minimizing the sum of the squared errors (SSR) between the predictive and measured distresses. A comparison was made between the results before and after the calibration to assess the improvement in accuracy of the distress prediction models provided by the local calibration. Both alligator cracking and longitudinal cracking models were improved by local calibration. However, there was a high degree of variability between the predicted and measured distresses, especially for longitudinal cracking, even after the calibration. It is recommended that additional sites, which would contain more detailed inputs (mostly Level 1), be established to be included in the future calibration efforts and thus, improve the accuracy of the prediction models.
  Authors: Rahman, Md Shaidur; Williams, Ronald Christopher; Scholz, Todd
  Authors: Rahman, Md Shaidur; Williams, Ronald Christopher; Scholz, Todd
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 318
  Paper Number: 13-4347
• Relationships Among Road Geometry, Drivers’ Risk Perception, and Speed Choice: Experimental Study
  Abstract: This paper presents the results of an experimental trial conducted on a population of 64 road users. Test participants drove a vehicle equipped with GPS on an oval racetrack. The GPS system returned the position and the speed of the vehicle. The objectives of this study are to analyze1) the correlation between risk and the speed perceived by the drivers, 2) the influence of the geometric layout on the perceived risk, 3) the influence of the familiarity with the environment on the perceived risk, 4) the analytical perception of the speed. Test participants were recruited to drive the test track for a total of 18 laps. The population demographics have been identified through a questionnaire. Three different scenarios have been conducted during the experimental trials. The scenarios consisted of different driving instructions given to the drivers, namely 1) the adoption of three vehicle speeds indicated qualitatively (low, medium, high) with no real time information to the driver about the speed, 2) the adoption of three speeds indicated quantitatively with no real time information to the driver about the speed, 3) the adoption of three speeds indicated qualitatively (i.e., using a low, medium and high level of safety) with real time information on the speed to the driver. The study permitted to identify a correlation between risk perception and drivers’ familiarity with the test track. The test also showed the relationship between speeds and perceived risk and the relationship between speed and the geometric layout of the racetrack.
  Authors: Colonna, Pasquale; Aquilino, Rita Alessandra; Berloco, Nicola; Ranieri, Vittorio
  Authors: Colonna, Pasquale; Aquilino, Rita Alessandra; Berloco, Nicola; Ranieri, Vittorio
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 544
  Paper Number: 13-4373
• International Roughness Index Models for Hot-Mix Asphalt Overlay Treatment of Flexible and Composite Pavements for Louisiana
  Abstract: Timely rehabilitation and preservation of pavement systems are imperative to maximize benefits in terms of driver’s comfort and safety. However, the effectiveness of any treatment largely depends on the time of treatment and triggers governed by treatment performance models. This paper presents the development of International Roughness Index (IRI) models for overlay treatment of composite and flexible pavements in the state of Louisiana. Various factors affecting the IRI of overlay treatment were identified. New climatic factors were developed and regression analysis was conducted and IRI prediction models were generated. The models provided a good agreement between the measured and predicted IRI values with majority of data within 5% of prediction error. The models could be used as a good pavement management tool for pavement maintenance and rehabilitation actions.
  Authors: Khattak, Mohammad Jamal; Nur, Mohammad Abdullah; Bhuyan, Mohammad Reza-ul Karim; Gaspard, Kevin
  Authors: Khattak, Mohammad Jamal; Nur, Mohammad Abdullah; Bhuyan, Mohammad Reza-ul Karim; Gaspard, Kevin
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-4396
• Surface Characteristics of Ultrathin Bonded Wearing Course Preservation Treatments
  Abstract: Ultrathin bonded wearing course (UBWC) has been used by many states as a pavement preservation treatment, particularly on high traffic volume roads. This paper presents the results of a research conducted to evaluate the surface properties of UBWC pavements placed by the Indiana Department of Transportation (INDOT). Four UBWC test sections were selected with respect to their service times, traffic volumes, and roadway functions. Surface friction testing was conducted every six months since the completion of construction. Field testing was also conducted to determine the characteristics of surface macrotexture. The type and gradation of aggregates used in the UBWC mixes were examined to identify their effects on the friction properties of UBWC. It was found that UBWC is capable of providing sufficient and consistent skidding resistance to allow quick opening to traffic. The friction numbers in the UBWC test sections tended to peak approximately 6 months earlier compared to conventional HMA mixes. The mean profile depth (MPD) of macrotexture for UBWC pavements is around 1.0 mm, which is much greater than that for conventional 9.5-mm HMA pavements, and very close to that for SMA pavements. However, the microtexture may play an important role in the development of UBWC surface friction. UBWC can provide sound, durable surface friction, but requires highly polish-resistant aggregates.
  Authors: Li, Shuo; Yang, Yonghong; Guan, Bowen; Zhao, Guangyuan; Harris, Dwayne; Jiang, Yi; Noureldin, A. Samy
  Authors: Li, Shuo; Yang, Yonghong; Guan, Bowen; Zhao, Guangyuan; Harris, Dwayne; Jiang, Yi; Noureldin, A. Samy
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 552
  Paper Number: 13-4436
• Evaluation of the Structural Response of Cracked Pavements at CEDEX Test Track
  Abstract: Flexible pavement structural response is typically modeled by using multilayer linear elastic theory. This is applicable to almost all mechanistic-empirical design procedures, but also in other fields of pavement engineering, like the interpretation of deflection data in order to assess pavement structural condition. The applicability of this theory, even with some limitations, has been validated for new or undamaged pavements, where the hypothesis of continuity is reasonably realistic. But still an effort is required in order to understand the structural response of damaged pavements, where the presence of discrete cracks is not compatible with continuum mechanics theories.Three flexible sections were instrumented with sensors in order to measure the structural response under moving vehicles at CEDEX test track. The response was systematically measured in terms of different response variables during a full-scale experiment where 1.3 million loads where applied. Structural response measured at the beginning of the experiment, when asphalt damage was null, was used as a reference in order to compare the evolution during the test. It was shown that the evolution of the different response variables can be explained by continuum mechanics, in particular by linear elasticity, as soon as asphalt damage is uniformly distributed in the material. As soon as discrete cracking appears, response stars to deviate from that predicted by multilayer linear elastic models.The importance of adopting a rational approach for the determination of the modulus of the asphalt layers is also shown in this paper.
  Authors: Mateos, Angel; Ayuso, Javier P.; Cadavid Jáuregui, Belén
  Authors: Mateos, Angel; Ayuso, Javier P.; Cadavid Jáuregui, Belén
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 574
  Paper Number: 13-4458
• Effects of High-Modulus Asphalt Binders on Performance of Typical Asphalt Pavement Structures
  Abstract: High modulus asphalt binders (HMABs) have been widely studied in the last 10 years. One of the most significant advantages of HMABs is their rutting resistance. In this study other factors related to the performance of HMABs in pavement engineering were studied: stiffness, elastic recovery, asphalt layer thickness reduction, workability and thermal cracking resistance. One neat binder, one hard-grade paving asphalt binder, three high modulus modifiers, and linear styrene-butadiene-styrene were included. Rotational viscosity, frequency sweep, elastic recovery and bending beam rheometer tests were performed. MEPDG software (Mechanistic-Empirical Pavement Design Guide) was selected to analyze whether HMABs could reduce the thickness of wearing or binder course. Workability was evaluated by measuring the effect of mixing temperatures of HMABs using a newly proposed method for evaluating coating using coarse aggregate water absorption. Results showed that HMABs had higher stiffness and elasticity than neat binder (Performance Grade 64-22). Based on MEPDG analysis for the same total pavement permanent deformation, it was estimated that the asphalt layer thickness was reduced by 8.9 to 27.9% by replacing the neat binder with HMABs in the study. Pavements constructed with HMABs had slightly less bottom up cracking than pavements constructed with neat binders. The coarse aggregate absorption method provided evidence that acceptable coating could be achieved at reasonable mixing temperatures for HMABs. A drawback of HMABs was the slight decrease in the low temperature performance grade. The application of HMABs where the low design temperature of the pavement is lower than -16 ¡ãC should be with caution.
  Authors: Geng, Han; Clopotel, Cristian; Bahia, Hussain U.
  Authors: Geng, Han; Clopotel, Cristian; Bahia, Hussain U.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 377
  Paper Number: 13-4423
• Comparison between wide base single tire and dual tires assembly based on experimental pavement response and predicted damage
  Abstract: Past studies suggest that Wide-Base Single Tires (WBST: 455/55R22.5) induce pavement strains, which are different than duals of similar sizing, some higher and some lower depending on the direction and the location in the pavement. An experimental assessment of strain basins occurring at various positions within the hot-mix asphalt (HMA) layer as well as within the pavement unbound layers was undertaken to further this understanding. The method and results of this assessment along with the pavement damage predicted using available models is presented in this paper. Four failure mechanisms were considered; HMA rutting, bottom-up and top-down fatigue cracking, and structural rutting. Testing was conducted at two sites on a total of four different roads over a range of loads, pressures, and temperatures, using WBST and different sizes of dual tires. Analysis of data showed several critical strain zones near the tire edges and at the tire center. Optic fiber sensors allowed analyzing these phenomena. HMA rutting was calculated considering vertical shear strain near the surface under the edge of the tires. The other failure mechanisms were calculated using maximum strain. The results predict that the WBST tested may induce less damage in the upper part of the HMA layer and more damage considering fatigue cracking and rutting of soils and unbound materials. The data collected was from specific tires and all tests were conducted only under smooth, steady-state rolling conditions. Thus, results should not be generalized to all tires nor extrapolated to predict actual field performance.
  Authors: Grellet, Damien; Doré, Guy; Bilodeau, Jean-Pascal; Gauliard, Thomas
  Authors: Grellet, Damien; Doré, Guy; Bilodeau, Jean-Pascal; Gauliard, Thomas
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 554
  Paper Number: 13-4494
• Improving Durability and Constructability of Connections for Prefabricated Bridge Elements and Systems: Recommendations and Special Provisions
  Abstract: Prefabricated Bridge Elements and Systems (PBES) is an integral part of Accelerated Bridge Construction (ABC) projects. The prefabricated components are required to be in good quality that is verified by strict quality control during manufacture and acceptance. In ABC, components are assembled and connected through field-cast joints. Construction of durable bridges not only requires good quality prefabricated components, but also durable connections. However, durability performance records of the field-cast connections are not encouraging. The majority of the durability problems are associated with the connection details, grout material properties, workmanship, application procedures, and quality assurance and quality control practices. Further, post-construction reports have documented challenges in selecting the grout material with properties compatible to those listed in the construction documents. Identifying the appropriate grout material depends on many parameters such as (a) site specific exposure conditions, (b) grout pocket dimensions, (c) application procedures and limitations, (d) curing and protection requirements and also (e) grout properties such as compressive strength, volume stability, initial setting time or working time, and application temperature range. This article describes (1) a grout property database, (2) specification of grout and special mix properties early in a project for connection detail design to assure constructability, and (3) a special provision template for material selection, leveraging contractor experience, and enhancing durability and constructability of PBES connections.
  Authors: Mohamed Ibralebbe, Mohamed Rusthi; Attanayake, Upul Bandara; Aktan, Haluk M.
  Authors: Mohamed Ibralebbe, Mohamed Rusthi; Attanayake, Upul Bandara; Aktan, Haluk M.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 498
  Paper Number: 13-4497
• DARwin-ME Evaluation of Flexible Pavements in Louisiana
  Abstract: This paper presents a recent study on using the DARWin-ME pavement design software to evaluate the performance of typical Louisiana flexible pavement structures as compared to pavement performance data available in the pavement management system. The overall comparison results indicated that the DARWin-ME rutting models over-predicted the total rutting for Louisiana flexible pavements; whereas, both fatigue and smoothness models in DARWin-ME seemed to be adequate for most pavements evaluated. A special optimization approach was used to determine a set of preliminary local calibration factors for DARWin-ME rutting models based on Louisiana conditions. A sensitivity analysis of DARWin-ME was also performed to determine if a small variation in design inputs would significantly affect the design asphalt concrete layer thicknesses. The results revealed that a 20 percent variation among each of primary design inputs could result in a design thickness variation of approximately 1.5 in.
  Authors: Wu, Zhong; Yang, Xiaoming; Zhang, Zhongjie
  Authors: Wu, Zhong; Yang, Xiaoming; Zhang, Zhongjie
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 318
  Paper Number: 13-4516
• Influence of Temperature on Tire-Pavement Friction-2: Analyses
  Abstract: Past experimental studies show that the tire-pavement friction values are related to tire surrounding conditions such as pavement temperature, ambient temperature, contained air temperature and surface characteristic of pavement. Various road agencies use correlation factors to estimate frictional characteristics of the road tested in various temperature conditions. These correlation factors are mainly based on the experience and field test measurements which has a very limited scope in terms of transferability. This paper studies frictional behavior of test tire under different surrounding temperature conditions using the finite element model. The scope of this research is to analyze the effect of pavement temperature, ambient temperature and contained air temperature on frictional measurements. Finite Element models of fully and partially skidding tires over different asphalt pavement surfaces, namely, Porous Asphalt, Ultra-Thin Surface and Stone Mastic Asphalt are analyzed. It was observed that pavement with high macrotexture results in high hysteretic friction. It was also observed that a higher pavement temperature, ambient temperature and contained air temperature would result in a lower hysteretic friction for a given pavement surface and a given tire slip ratio. On the other hand, a lower tire slip ratio and a pavement with higher macrotexture would result in a higher friction. This study shows that a critical combination of these factors may decrease the friction values significantly.
  Authors: Anupam, Kumar; Srirangam, Santosh Kumar; Scarpas, Athanasios; Kasbergen, Cor
  Authors: Anupam, Kumar; Srirangam, Santosh Kumar; Scarpas, Athanasios; Kasbergen, Cor
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 384
  Paper Number: 13-4521
• Crash Severity Analysis at Roundabouts: Case Study in Quebec, Canada
  Abstract: Numerous studies both in North America and abroad have studied the roundabout as a means to improve the capacity and safety of intersections. The focus of these studies has been to reduce both the number and the severity of accidents, and have generally come to agreeable results. Nevertheless, few studies have dealt with the identification of accident factors within roundabouts. The varied physical and environmental characteristics of Quebec’s roundabouts and the behavioral traits of its drivers requires further study in order to help reduce the occurrence and severity of accidents. This paper presents a crash severity analysis to identify the effects of different contributing factors on injury severity outcomes. To achieve this, an ordered logit modeling technique was used for the analysis. Moreover, an important effort was made to integrate an accident database containing accident records from the year 2000 to 2011. Among other results, it was found that factors such as a larger number of involved vehicles, accidents occurring within the intersection, vehicle rollovers, the involvement of buses, accidents occurring in the dark on unlit roads and snow conditions led to increased injury severity within roundabouts, whereas factors associated to accidents involving only cars, animal strikes and snow-covered roadways were found to reduce the likelihood of severe injuries.
  Authors: Burns, Shaun; Miranda-Moreno, Luis Fernando; Saunier, Nicolas; Ismail, Karim
  Authors: Burns, Shaun; Miranda-Moreno, Luis Fernando; Saunier, Nicolas; Ismail, Karim
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-4527
• Behavior of Bell and Spigot Joints in Buried Reinforced-Concrete Pipelines
  Abstract: The behavior of joints in reinforced concrete pipes when buried and subjected to service live loading needs to be assessed to define the expected response of these elements. Excessive rotation and/or shear across the joint could generate leakage and subsequent loss in soil support which can bring the system to its serviceability or resistance limits. Two reinforced concrete pipelines with bell and spigot joints, one 600 mm (24 in.) and the other 1200 mm (48 in.) in diameter, were buried and subjected to surface loads. The pipelines were examined under AASHTO Type 2 installation conditions, at two burial depths, and applying the maximum service live loading at three independent locations above the pipeline. In addition, the smaller specimen was tested under burial conditions not specified by AASHTO where the protruding bells were placed directly on the stiff foundation. Subsequently, each pipeline was tested up to and beyond the fully factored load at shallow cover under AASHTO Type 2 installation and applying the load directly over the central joint. The displacement of the joint and barrels for each pipeline was monitored employing reflective prisms, and strain gages were attached in the main joint and barrels of the 600 mm (24 in.) diameter specimen. The response of these joints due to variations of burial depth, burial conditions and loading locations when subjected to live loads is presented and discussed, and recommendations are made regarding development of structural design requirements for rigid pipe joints.
  Authors: Becerril Garcia, David; Moore, Ian D.
  Authors: Becerril Garcia, David; Moore, Ian D.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 782
  Paper Number: 13-4577
• Characteristics of Multimodal Conflicts in Urban On-Street Bicycle Lanes
  Abstract: In urban areas, bicycles traveling in bicycle lanes encounter a variety of obstructions, including pedestrians and various types of motor vehicles. While previous studies have focused on identifying the frequency of such events, the goal of this study is to characterize these conflicts. In order to evaluate specific characteristics that may influence the frequency of specific conflict types, including bicycle lane designs, curb regulations, and land uses, field data collection was performed in the Manhattan and Brooklyn boroughs of New York City. This paper describes a method for evaluating the frequency of conflicts between bicycles traveling in on-street bicycle lanes and various other transportation modes, and for identifying factors that may impact these frequencies .
  Authors: Conway, Alison J.; Cheng, Jialei; Peters, Diniece; Lownes, Nicholas E.
  Authors: Conway, Alison J.; Cheng, Jialei; Peters, Diniece; Lownes, Nicholas E.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-4545
• Modeling and Calibration of Concrete Slab Interfacial Effects
  Abstract: For many years, concrete pavement construction, whether new or overlay, has been done with a variety of layer interfaces ranging from strongly cemented having a high degree of shear strength to completely unstabilized having only internal frictional resistance between the individual particles. In this regard, both past and present design methodologies have been limited in their capability to address the bond between the slab and the underlying layers – essentially considering either unbonded or fully bonded conditions for design purposes. However, this limitation ignores a wide range of partially bonded conditions that can exist between these two limits that may consist of a variety of combinations of different levels of friction and adhesion. For most instances of design, unbonded conditions are principally hypothetical where qualification of the amount of adhesive strength and frictional restraint that develops along the interfacial between the slab and the underlying layer is key to the characterization of slab behavior resulting for varying degrees of partial bond. This paper addresses a framework to model the effects of the concrete pavement slab/subbase interface for design purposes relative to these and other factors as they may pertain to the prediction of short and long term performance.
  Authors: Bari, Muhammad Ehsanul; Zollinger, Dan G.; Jung, Youn su
  Authors: Bari, Muhammad Ehsanul; Zollinger, Dan G.; Jung, Youn su
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 236
  Paper Number: 13-4607
• Severity of Pedestrian Crashes at Highway-Rail Grade Crossings
  Abstract: The objective of this research was to quantify the impacts of various factors on three different severity levels of pedestrian injuries sustained in crashes reported at highway-rail grade crossings (HRGCs). This research utilized the 2007-2010 HRGC crash data and the national highway-rail crossing inventory data, both publically available from Federal Railroad Administration (FRA). HRGC crash data were limited to those reported at public crossings and only involving pedestrians; crashes that were suicides or attempted suicides were excluded. The three crash severity levels were based on the intensity of pedestrians’ injuries; these levels were no injury, injury, and fatality. The crash and crossing inventory data files were merged together using the unique USDOT crossing identification number that was common in both files. The ordered probit modeling technique was used to investigate different variables that contributed to more severe pedestrian injuries in crashes at HRGCs. Model results showed that more severe injuries were associated with higher train speeds and when rail equipment struck pedestrians as opposed to rail equipment struck by pedestrians. Injury severity was higher for female pedestrians compared to others. Pedestrian crashes reported at HRGCs surrounded by commercially developed areas were more severe compared to other types of developments (e.g., open space, residential, etc.). Lower crash severity levels were associated with HRGCs with greater number of crossing highway lanes, HRGCs equipped with standard flashing light signals, and in clear weather.
  Authors: Khattak, Aemal
  Authors: Khattak, Aemal
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-4587
• Assessment of Reliability and Load Factor Design Approach Against Fatigue Cracking in Flexible Pavements
  Abstract: A reliability based approach to design flexible pavements against bottom-up and top-down fatigue cracking has been developed. The approach involves the use of load factors applied to the nominal fatigue cracking values to obtain the failure values in field. The uncertainty in input parameters has been modeled via Weibull and Lognormal distribution of the damage index with different values of skewness and coefficient of variation. The field data from Long Term Pavement Performance database have been used to model the uncertainty in prediction between the nominal (predicted) and the field cracking. The probability density function of fatigue cracking was found to be unsymmetrical in nature; the skewness of the distribution changes with the level of damage. The nonlinear limit state performance function has been used to determine the reliabilities and the load factors using Monte Carlo simulation. The differences between the failure values obtained from the standard Gaussian assumption and the simulation have been observed. Design charts and load factor tables have been developed which can be used with the newly developed Mechanistic Empirical Pavement Design Guide for designing new and rehabilitated pavements. Finally, the use of the load factors in flexible pavement design has been presented via practical examples.
  Authors: Bhattacharjee, Sudip
  Authors: Bhattacharjee, Sudip
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 242
  Paper Number: 13-4632
• Behavior of Bell and Spigot Joints in Buried Thermoplastic Pipelines
  Abstract: Failures in joints are among the most common sources of problems in buried gravity flow pipelines. Poor performance of these elements can cause infiltration and exfiltration, which leads to soil erosion and eventually serviceability or strength limits states for the soil-structure system. To prevent this, joints should be designed to adequately accommodate the demands generated under normal loading conditions. However, such demands are not clearly understood, since joint behavior has received scant attention. Thus the goal of this research is to examine the response of joints in two thermoplastic pipelines employed in gravity flow applications when subjected to live loading. The specimens examined were a 1500 mm (60 in.) diameter High Density Polyethylene (HDPE) pipeline and a 900 mm (36 in.) diameter Polyvinyl Chloride (PVC) pipeline, both specimens with gasketed bell and spigot joints. Two burial depths and three different loading locations were examined for each pipeline buried according to AASHTO Type 2 installation. Moreover, two installations not specified by AASHTO were examined for the PVC specimen, which featured voids in the bedding under the joint. Finally, each specimen was loaded directly over the joint up to and beyond fully factored loads to observe the joint performance under this condition and the final failure mode of the pipelines. The specimens were instrumented with string potentiometers and reflective prisms to monitor changes in diameter in the joint and barrels, and to obtain patterns of vertical displacements along the pipeline. The observed response for each pipeline is presented and discussed here and recommendations are made regarding the development of structural design procedures.
  Authors: Becerril Garcia, David; Moore, Ian D.
  Authors: Becerril Garcia, David; Moore, Ian D.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 782
  Paper Number: 13-4591
• Injury Risk due to Side Impact of Non-Tracking Vehicles into Guardrail
  Abstract: One of the most dangerous types of guardrail crash is side impact. Of particular concern is when a non-tracking vehicle slides sideways into a guardrail end treatment. This study has investigated the issue of end terminal side crashes using a dataset of 142 guardrail crashes extracted from the National Automotive Sampling System / Crashworthiness Data System (NASS/CDS). Side crashes involving an end terminal are substantially over-represented in driver injuries. End terminal contact occurs in about 25% of all guardrail side crashes but represents almost 70% of driver injuries. Non-crashworthy terminals are roughly twice as likely as crashworthy designs to cause serious injury. Terminals are also about twice as likely to initiate rollover than length of need. When injuries due to drivers in rollover, unbelted drivers and driver ejection are accounted for, the risk presented by terminal contact is accentuated, as is the difference between cars, light trucks, and vans in terminal impacts.
  Authors: Johnson, Nicholas Sean; Gabler, Hampton Clay
  Authors: Johnson, Nicholas Sean; Gabler, Hampton Clay
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-4694
• Combined Effect of Three-dimensional Tire-Pavement Contact Load and Thermal Load on Cracking Performance of Heavy-Duty Asphalt Pavements
  Abstract: Top-down cracking (TDC) has been well recognized as a major distress for the heavy duty asphalt pavements yet the mechanism is still not fully understood. Studies indicated the non-uniform tire-pavement contact stress might play a significant role in the initiation of TDC, and thermal stress due to temperature gradient might contribute to the initiation and development of TDC. For this concern, a sophisticated three-dimensional (3-D) viscoelastic finite element model was developed to study cracking performance of heavy duty flexible pavements under combined 3-D tire-pavement contact stress and thermal stress induced by temperature gradient. It was found the stress distribution in asphalt concrete (AC) layer is continuously changing as the pavement is loaded due to rheological behavior of AC. Significant maximum principal tensile stresses are presented at the edge of tire at AC surface, which may result in an accumulation of dissipated creep strain energy (DCSE) over time (or with number of loads) and may eventually lead to the initiation of a crack. And pavement near-surface responses associated with top-down cracking under 3-D contact pressure is more severe as compared to uniform contact pressure. Comparing with pavements without thermal effect, the negative temperature gradient increases the potential for top-down cracking while the positive temperature gradient increases the potential for bottom-up cracking. The study may provide some meaningful insight into crack mechanisms and help improve current heavy duty asphalt pavement design procedures for cracks.Key words: Viscoelastic; 3-D; TDC; Temperature; Contact Stress; Pavement.
  Authors: Wang, Guangming; Morian, Dennis A.; Frith, Douglas
  Authors: Wang, Guangming; Morian, Dennis A.; Frith, Douglas
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 242
  Paper Number: 13-4699
• Using Vehicle Simulations to Understand Needs and Strategies for Accommodating Oversize, Overweight Vehicles at Roundabouts
  Abstract: There is considerable evidence that roundabouts are the safest and most efficient form of traffic control for most intersections. The potential use of roundabouts with all their inherent benefits may be greatly diminished if they are not able to accommodate oversize/overweight vehicles, sometimes called “Superloads”. To use these OSOW vehicles as a design vehicle for roundabouts could negate the benefits of roundabouts which rely on being designed to operate at slower speeds from adequate deflection. The problem, therefore, is how to accommodate OSOW vehicles without sacrificing the integrity, safety and other benefits of roundabouts.This study uses TORUS software to design six standard roundabouts using guidance from the Federal Highway Administration (FHWA) latest roundabout guide (NCHRP 672). Six OSOW check vehicles from the Wisconsin Department of Transportation’s (WisDOT) library were used to modify the designs to accommodate these selected check vehicles at the roundabouts. These six OSOW check vehicles were used to conduct swept path analysis using AutoTURN software at the selected six standard roundabouts for right turn, through, and left turn simulations and their space requirements were analyzed in detail. Various strategies for better accommodating these OSOW check vehicles were suggested and experimented with in this study. The effectiveness of using a straight passage through the center island for OSOW vehicles was also addressed in this study and was found to be effective. The needed total truck apron was calculated for the accommodation strategies. Tables were presented to show the total truck apron area required for various accommodation strategies.
  Authors: Godavarthy, Ranjit Prasad; Russell, Sr., Eugene R.; Landman, Dean
  Authors: Godavarthy, Ranjit Prasad; Russell, Sr., Eugene R.; Landman, Dean
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-4725
• Unmanned Aerial Vehicle-Based Automatic Traffic Incident Detection System for Low-Volume Roads
  Abstract: This paper presents an automatic traffic incident detection system for low volume roads based on Unmanned Aerial Vehicle (UAV). Using computer vision techniques, the traffic flow parameters and vehicle trajectories were extracted from the real-time video. Then, various traffic incidents can be detected automatically by using the proposed algorithms, which can detect collisions that happened already or dangerous events that would result in collisions. A unique feature of the system is the Geographic Information System (GIS) based property while with Google Earth embedded, which enables the users to see real time large scale terrain image around the existing UAV location. This system supports video retrieving according to traffic semantics, such as stalling vehicles and vehicle running in wrong direction, which enables users to confirm incidents according to traffic video. To evaluate the performance of proposed system, two field experiments have been done. One was conducted in Gainesville, Florida U.S. in May, 2011. Another was carried out in Feb, 2012, China. In the first experiment, the video with 24567 frames contains 2 slow moving incidents, 3 wrong direction incidents, and 55 vehicle stalling incidents. The slow moving, wrong direction incidents detection rate is 100% and the vehicle stalling incident detection rate is 96.36%. For the second experiment, three test cars were driven to simulate incidents, all the vehicles including static ones were detected successfully when the UAV cruised along the highway.
  Authors: Zhang, Li-Ye
  Authors: Zhang, Li-Ye
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 571
  Paper Number: 13-4724
• Study of Accommodating Oversize, Overweight Vehicles at Roundabouts
  Abstract: Roundabouts can offer several advantages over signalized and stop-controlled intersection alternatives, including better overall safety performance, lower delays, shorter queues, better management of speed, and opportunities for community enhancement features. In some cases, roundabouts can avoid or delay the need for expensive widening of an intersection approach that would be necessary for signalization.However, potential use of roundabouts with all their benefits may be greatly diminished if they cannot accommodate oversize/overweight vehicles (OSOW). How to accommodate OSOW at roundabouts is the central issue and the need for this research.This research project is necessary to compile current practice and research by various states and countries related to the effects OSOW have on roundabout location, design, and accommodation. Second, the research will attempt to fill in information gaps with respect to roundabout design and operations for these classes of vehicles. Currently there is little information available for accommodating the OSOW vehicle classes in roundabout design.To obtain additional information and data needed to complete the stud, the following were performed:•Surveys of all the states and a sample of the trucking industry•Personal contact with designers and researchers and examples provided•Simulations of OSOW operations at roundabouts. Based on material gathered for this study, surveys and interviews, it may be possible to accommodate OSOW at roundabouts with designs that consider the following: widened entries and exits, unobstructed central islands with large truck aprons, outer truck aprons, bypass lanes and lanes through the center island, mountable curbs, no vertical obstructions on the splitter islands, easily mountable curbs 3 inches or less, and with signs, light poles etc. outside of the turning paths and/or designed to be easily removed.
  Authors: Russell, Sr., Eugene R.; Landman, Dean; Godavarthy, Ranjit Prasad
  Authors: Russell, Sr., Eugene R.; Landman, Dean; Godavarthy, Ranjit Prasad
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-4759
• Calibration and Application of Treatment Performance Models in Pavement Management System
  Abstract: To utilize the pavement management system (PMS) for maintenance strategy decision making, it is necessary to use locally calibrated performance models and other related parameters. In this study, the performance family models of typical asphalt resurfacing treatments used in Tennessee were calibrated for the PMS by investigating historical maintenance projects. Multiple regression method was employed to analyze the influence of pre-treatment PSI, traffic level, overlay thickness and milling depth on the post-treatment performance curves. The specific designs of asphalt resurfacings and performance classes were determined based on the regression analysis. Then, the performance curves for each identified treatment methods at different performance classes were established and calibrated for the PMS. Rehabilitation trigger values, typical treatments and decisions trees for pavement with different functional classes were determined and designed by investigating the historical maintenance projects. A network optimization using calibrated models and determined parameters was conducted by the PMS.Investigation on the treatment performance models indicated that pavement with lower pre-treatment roughness, thick overlay and deep milling deteriorated slower. Pavement with high traffic level tended to have lower post-treatment roughness. The distress condition decreases much faster than smoothness. Network optimization analysis of the PMS indicated the most cost-effective maintenance strategy can be determined by conducting a network optimization analysis with a sufficient high budget limit, in which the highest annual cost is lower than the budget limit. Several suggestions on how to use the budgets according to the HPMA analysis include combining cost-effective and worst-first, rolling over budget and redistributing budget among the four regions.
  Authors: Dong, Qiao; Huang, Baoshan; Richards, Stephen H.
  Authors: Dong, Qiao; Huang, Baoshan; Richards, Stephen H.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-4745
• Roundabout Versus Traffic Signal Control: Comparative Analysis
  Abstract: The research presented in this paper quantifies the efficiency, energy, and environmental impacts of single-lane and two-lane roundabouts compared to all-way stop control (AWSC), two-way stop control (TWSC), and traffic signal control. Furthermore, the research develops guidelines for the identification of the optimum intersection control as a function of the level of intersection demand, the distribution of demand across various approaches, and the distribution of approach demand between left, through and right turner movements. The research first compares the alternative control strategies using field data collected from two roundabouts in the Blacksburg Area. The field data are then used to validate the INTEGRATION software for the modeling of different intersection control strategies. The field data demonstrate that in both cases roundabouts are the optimum control strategy. The sensitivity analysis demonstrates that single-lane roundabouts are more effective for high through and right turn demand levels and less effective for high left turn demands in comparison to other isolated intersection control strategies. The two-lane roundabout results suggest roundabouts are effective regardless of the demand level and distribution of demand across the various movements.
  Authors: Wang, Zhao; Boon, Teck Ong; Rakha, Hesham
  Authors: Wang, Zhao; Boon, Teck Ong; Rakha, Hesham
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-4422
• Synthesis of Roundabout Geometric Capacity Measurement: Calibration and Validation to U.S. Field Measurements
  Abstract: The implementation of modern roundabouts in the U.S. began in the 1990s. Since then U.S. researchers and practitioners have increasingly debated which capacity estimation method(s) are most suited to U.S. conditions. Capacity research continues in the US, as it has for the past 50 years in some other countries.Early U.S. research concluded that international models over predict U.S. roundabout capacities. This has raised questions about the transferability of non US models to US conditions. Such questions include: are non US drivers more experienced with roundabouts: is their driver behavior different to US drivers? Does the different size of cars and trucks have an effect? Will such differences persist into the future?Recent independent capacity research on saturated roundabouts is providing increasing support for the transferability of the U.K. empirical capacity model to US conditions. This model derives capacity from detailed geometry, with six geometric parameters per leg. The wide range of all the geometric parameter encompasses entire spectrum of modern Roundabout design. This paper provides a synthesis of the development of the UK empirical model and reviews recent US research and data collection, comparing HCM 2010 calibration and validation and the transferability of the UK geometric capacity model to the US.
  Authors: Johnson, Mark T.
  Authors: Johnson, Mark T.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 542
  Paper Number: 13-4790
• Influence of Tire Configuration on Pavement Response and Predicted Distress
  Abstract: The 2011 TRB paper, titled "Pavement Shear Strain Response to Dual and Wide-Base Tires," (1) described the background, objective, analysis and partial results for the Hot Weather Shear loading tests conducted on the Strategic Highway Research Program (SHRP) Long-Term Pavement Performance (LTPP) Specific Pavement Study (SPS-8) asphalt concrete (AC) sections at the Ohio Test Road (OTR) on State Route 23 in Delaware County, OH. However the results presented in that paper were limited to one strain rosette sensor location. This paper describes analysis results and performance predictions from all other sensor locations.The data from all rosette sensors was analyzed for one speed and inflation pressure condition. The pavement response software 3D-Move was used to verify that measured values followed expected trends The comparison of strain in various direction at different locations of pavements reveals the difference and similarity of different tire configurations. Fatigue cracking and rutting models were used to present the damage brought by different tires to experimental sections. The effects of wide-base and dual tires to flexible pavement responses from two structural conditions are presented. Impacts on predicted fatigue and permanent deformation as a result of tire configuration are included, showing that pavement structure has a more influential role than tire configuration.
  Authors: Xue, Wenjing; Weaver, Eric
  Authors: Xue, Wenjing; Weaver, Eric
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 554
  Paper Number: 13-4810
• Roadway and Infrastructure Design and Its Relation to Pedestrian and Bicyclist Safety: Basic Principles, Applications, and Benefits
  Abstract: Road deaths are forecast to double by 2020, with the burden falling most heavily on low- and middle-income countries and, within those countries, on the most vulnerable and poorest road users. Half of the 1.2 million people killed and 50 million injured in road crashes each year are pedestrians, motorcyclists, bicyclists, and users of unsafe public transport; and more than 90 percent are from low- and middle-income countries. Because these are the areas where rapid motorization is taking place, the issue of safety in increasingly multi-modal environments is now of critical importance, particularly for pedestrians and bicyclists, since as vulnerable road users (VRU), they comprise a large proportion of injuries and deaths, and similar strategies for prevention of injuries and fatalities for these two groups are available. Although a great deal of additional research is needed to determine the costs and benefits of various proposed solutions, some basic principles can be identified to guide roadway and infrastructure design for improved pedestrian and bicyclist safety. The three broad but separate strategies for reducing the probability of an injury or fatality are: (i) reducing exposure, (ii) reducing the probability of a collision given exposure, and (iii) reducing the probability of injury given a collision. The purpose of this paper is to describe and illustrate these principles, discuss issues related to each one, and discuss the benefits—indeed, imperativeness—of the application of these principles by planners and traffic engineers.
  Authors: Ragland, David R.; Grembek, Offer; Orrick, Phyllis; Felschundneff, Grace
  Authors: Ragland, David R.; Grembek, Offer; Orrick, Phyllis; Felschundneff, Grace
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 222
  Paper Number: 13-4820
• Automated Analysis of Cyclist Crossing Speed: Validation and Investigation of Influencing Factors
  Abstract: This study investigates the use of an automated video analysis technique to calculate cyclist speed. The proposed technique enables the automated observation of large volume of naturalistic cyclist movements in a resource-efficient manner. Video data was collected for a total of 190 hours at a busy intersection in the Downtown area of Ottawa. Observations were distributed over the Fall and Summer seasons. Video subsequences were identified in which crossing was performed by one or more cyclists. Automated tracking was performed to record the sequence of positions which cyclists occupy while traversing an intersection. Extensive validation work was performed. The first validation experiment relied on the measurement of actual cyclist paths based on following the trace of bike tires to estimate average crossing speed. The second validation task utilized cyclist tracks which moved reasonable matched paths with measured lengths. The total number of crossing events in the first task was 16 and in the second task was 482. The average percentage of absolute difference between measured and actual speed for the first task was 5.22% and 4.98% for the second task. Statistical analysis was conducted to investigate the effect of different factors on average crossing speed and the error in speed measurement. Several observations are reported regarding patterns of tracking errors and recommendations are made for future improvements.
  Authors: Kassim, Ali; Ismail, Karim; Abd El Halim, Halim Omar
  Authors: Kassim, Ali; Ismail, Karim; Abd El Halim, Halim Omar
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-4879
• Analyzing Nighttime Visibility of In-Service Pavement Markings
  Abstract: Traditionally, retroreflectivity is used to quantify the visibility of traffic control devices, including pavement markings. However, retroreflectivity is a physical property of a material that is used as a surrogate for luminance. By itself, retroreflectivity is only limited in terms of describing the visibility of a pavement marking at night. One way to quantify the visibility of pavement markings at night is to assess the visibility level (VL) at the perspective of drivers’ visual demands. Based on the previous research on VL modeling, an extended VL model for pavement markings is introduced in the paper and used to determine the visibility of in-service pavement markings along lighted and unlighted highway sections in Anchorage, Alaska. We compare the measured pavement marking retroreflectivity with the FHWA proposed minimum required levels, and the calculated VL with the implied pavement marking visibility derived from the FHWA proposed minimum pavement marking retroreflectivity levels. The results indicate that areas with continuous roadway lighting appear to have more than adequate visibility despite having low retroreflectivity levels. The benefit of the roadway lighting was most evident when the pavement marking retroreflectivity was relatively low and at the longer distances tested (54 and 64 m).
  Authors: Ye, Fan; Carlson, Paul J.; Miles, Jeffrey David
  Authors: Ye, Fan; Carlson, Paul J.; Miles, Jeffrey David
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-4902
• Performance-Based Risk Estimation of Bridges Under Seismic Hazard
  Abstract: The present study develops a performance-based risk estimation framework for bridges located in seismically active regions. Instead of using code-specified design level earthquakes, seismic performance of bridges are evaluated under earthquake ground motions with various hazard levels. This enables the estimation of bridge seismic risk at different seismic performance levels starting from the full functional stage to an extensive damaged stage when the bridge needs to be closed from traffic. The framework is demonstrated through the development of seismic risk curves of a two-span reinforced concrete bridge. Progressive damage data of the bridge is obtained from large-scale shake table tests that are performed in series with increasing seismic intensities. Seismic performance levels of the bridge at different stages during the experiment are assigned to categorize observed bridge damage (physical) in various seismic damage states. Numerical simulations are performed to generate seismic damage data of the bridge under a suite of earthquake ground motions with various hazard levels. These simulated damage data are used in a probabilistic analysis and fragility characteristics of the bridge at the pre-defined seismic damage states are estimated. Developed fragility curves are used to generate seismic risk curves of the bridge. Risk curves exhibit annual exceedance probabilities for various levels of expected direct losses arise due to the repair of bridge damage resulting from regional seismic hazards. Results obtained from this study show a nonlinear increase in seismic risk of the bridge when it has more damage due to seismic activity. Such risk curves are the foundation for decision-making on post-event bridge repair or replacement. These curves also facilitate the development of a rapid yet cost-effective post-seismic bridge restoration process.
  Authors: Banerjee, Swagata; Chi, Chao
  Authors: Banerjee, Swagata; Chi, Chao
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 750
  Paper Number: 13-4924
• Conflict Analysis and Crash Severity Estimation of Four Transportation Modes in China
  Abstract: This study attempts to analyze conflict and estimate the crash severity for users of four transportation modes in China -- automobile, motorcycle, e-bike and bicycle. Surveys were performed in Kunming and Beijing to collect self-reported crash data of these users. The surveys indicated that Beijing residents have lower crash rate than people in Kunming. Among the four modes, E-bike riders have the highest crash rate, motorcycle riders have the second highest crash rate, automobile and bicycle users have the lowest crash rate. Vehicle operators are more likely to crash with other users of the same vehicle class than with other types of vehicles. Respondents are more likely to say the crash is because of other's fault or both side's fault than admitting it is their fault. Logistic regression models were constructed to predict the crash severity level. Results show that crashes involving motorized vehicles generally are more likely to be severe than crashes involving the non-motorized vehicles. Crashes occurring in an automobile lane have higher crash severity than crashes happening in a bicycle lane or sidewalk. Crashes occurring at Beijing are less likely to be severe than crashes in Kunming. Countermeasures should focus on maintaining segregated and protected travel ways for vulnerable road user groups.
  Authors: Yang, Hongtai; Cherry, Christopher R.
  Authors: Yang, Hongtai; Cherry, Christopher R.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-4926
• Factors Influencing Life-cycle Performance of Pavement Utilizing Decision Tree Analysis
  Abstract: Accurate prediction of pavement performance during its lifecycle plays an important role in selecting the most cost-effective solution during pavement type selection process. However, State Highway Agencies (SHAs) have reported lack of consensus between asphalt and concrete industries on life-cycle cost analysis (LCCA) models utilized for pavement type selection. This is despite the fact that the Oklahoma Department of Transportation (ODOT) along with other state DOTs stores a large amount of highway project data throughout the life-cycle of highway projects. This paper applies the decision tree analysis in data mining to the historical pavement treatment data set available in the ODOT in order to identify the timing of maintenance and rehabilitation (M&R) activities. The data is divided into training and validation data sets. Therefore the models are created utilizing the training data set then their complexities are optimized to minimize the classification errors utilizing the validation data set. The results of the classification trees indicate that categorizing performance of pavement sections based on the type of material and level of traffic create errors in predicting the performance of pavements. Utilizing the historical pavement treatment projects, new criteria are identified in this paper that predicts the timing of M&R strategies adopted by ODOT. Since decision tree models developed in this paper are based on the actual treatment strategies performed by ODOT, it is expected that classifying pavement sections based on these factors help in predicting the future performance of pavement more accurately.
  Authors: Abdollahipour, Saeed; Jeong, David Hyung Seok
  Authors: Abdollahipour, Saeed; Jeong, David Hyung Seok
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 659
  Paper Number: 13-4983
• Behavior of Laterally Damaged Bridge Girders Repaired with CFRP Laminates Under Fatigue and Static Loading
  Abstract: This study investigates the optimum configurations of carbon fiber reinforced polymers (CFRP) laminates to repair laterally damaged prestressed concrete (PSC) bridge girders due to impact by over-height vehicles collision. Experimental and analytical investigations were conducted to determine the most efficient CFRP repair configuration to restore girders’ flexural capacity. Impact damage was simulated in the lab by (1) concrete damage and (2) reducing the prestressing force by cutting some of the prestressing strands. The repair systems for eight 40-ft-long AASHTO Type II PSC girders and thirteen half-scale 20-ft-long PS girders were designed to restore the original ultimate flexural capacity.In addition to the static load tests, some of the girders were tested under fatigue loading for 2 million cycles to examine the behavior under simulated traffic conditions. The study investigated and recommended the proper CFRP repair design in terms of the CFRP longitudinal layers and U-wrapping spacing to obtain flexural capacity improvement and desired failure modes for the repaired girders. The analysis of the test results investigated the most efficient CFRP configurations having evenly spaced transverse U-wrappings that provided an efficient configuration to mitigate debonding of soffit CFRP longitudinal laminates. Test results showed that with proper detailing, CFRP systems can be designed to restore the lost flexural capacity and maintain the desired failure mode.
  Authors: Elsafty, Adel; Fallaha, Sam
  Authors: Elsafty, Adel; Fallaha, Sam
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design
  Session: 426
  Paper Number: 13-5000
• Development and Initial Testing of Total Pavement Acceptance Device
  Abstract: A new, multi-function pavement testing device has been developed by a joint effort between the Texas Department of Transportation (TxDOT), the Center for Transportation Research (CTR) at the University of Texas at Austin (UT) and the Texas Transportation Institute (TTI) at Texas A&M University. This new device is called the Total Pavement Acceptance Device (TPAD). The objective of TPAD testing is to nondestructively and nonintrusively investigate the total pavement’s structural adequacy. The multiple functions of the TPAD presently include the following measurement capabilities: (1) rolling dynamic deflectometer (RDD), (2) ground penetrating radar (GPR), (3) global positioning system (GPS), (4) pavement surface temperature, (5) digital video imaging of pavement and right-of-way conditions, and (6) longitudinal survey offsets through a distance measurement instrument (DMI). The TPAD is designed to perform continuous measurements at speeds around 3.2 to 4.8 km/hr (2 to 3 mph), with increased speeds planned in future developments. The main developmental efforts have focused on developing: (1) a moving platform with precise speed control in the range of 0.8 to 16 km/hr (0.5 to 10 mph), (2) automated RDD pavement loading and deflection sensing systems, (3) an improved analysis scheme for processing RDD deflection data on the fly over incremental distances of 6 to 30 cm (0.2 to 1 ft) and (4) a new data collection system that integrates the results from all measurement functions and displays them in real time. Descriptions of the equipment and example sets of continuous RDD pavement deflections and GPR evaluations are presented.
  Authors: Stokoe II, Kenneth H.; Lee, Jung-Su; Nam, Boo Hyun; Scullion, Tom; Liu, Wenting; Leidy, Joe; Claros, German J.
  Authors: Stokoe II, Kenneth H.; Lee, Jung-Su; Nam, Boo Hyun; Scullion, Tom; Liu, Wenting; Leidy, Joe; Claros, German J.
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 260
  Paper Number: 13-5040
• Assessment of Emission Costs due to Maintenance and Rehabilitation to Reduce Pavement Roughness
  Abstract: Asphalt pavements constitute a major portion of the transportation network of the United States and play an important role in the US economy. Poor roadway conditions create user delay costs and additional user costs i.e. fuel, vehicle repair and maintenance, tire wear, depreciation, etc. due to the effects of pavement roughness. A previous investigation showed that pavement rehabilitation resulting in maintaining smoother pavement could result in as much as a 50-to-1 return on investment (ROI); however, the study did not consider the environmental impacts of construction, maintenance, and rehabilitation (CMR) activities. In this study, emissions due to CMR activities and pavement roughness have been quantified in monetary terms using PaLATE and MOVES program. While the environmental impact of CMR activities tends to reduce the ROI, maintaining relatively smooth pavement throughout its service life is still estimated to create an approximate 48-to-1 ROI.
  Authors: Islam, Shahidul; Buttlar, William G.
  Authors: Islam, Shahidul; Buttlar, William G.
  Year: 2013
  Document Type: Paper
  Subject: Design; Environment; Pavements
  Session: 660
  Paper Number: 13-5084
• Assessing the Completeness of Bicycle Trail and Designated Lane Features in OpenStreetMap for the United States and Europe
  Abstract: This paper assesses the completeness of OpenStreetMap data for cycling features, in particular bicycle trails and designated lanes, for selected cities in the United States and Europe. While most available comprehensive road network datasets, either from commercial data vendors or public agencies, are tailored towards motorized traffic, OpenStreetMap as a community based, open access platform for geospatial vector data provides a viable alternative for data retrieval of cycling feature data. The analysis in this study reveals a steady growth of cycling related data in the OpenStreetMap platform over the past few years, rendering the data more complete and appropriate to be used as base map for planning studies on non-motorized transportation. A comparison with the Google Maps Bicycling layer shows that the data quality of OpenStreetMap designated lanes is particularly high. OpenStreetMap bicycle trail data are somewhat more erroneous through missing data and incorrectly classified trails, however still of relatively good quality. For practical purposes it is recommended to check OpenStreetMap trail data against the Google Maps Bicycling layer before an analysis is conducted based on OpenStreetMap trail data.
  Authors: Hochmair, Hartwig; Zielstra, Dennis; Neis, Pascal
  Authors: Hochmair, Hartwig; Zielstra, Dennis; Neis, Pascal
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 494
  Paper Number: 13-5099
• Dynamic Characterization of a Truss Bridge by Falling-Weight Deflectometer
  Abstract: There are several full-scale testing methods that can be used to characterize and evaluate the global performance and condition of bridges. These global methods mainly consist of static load tests and dynamic testing methods using either controlled or uncontrolled dynamic excitation. Each approach has advantages and disadvantages with respect to experimental and logistical considerations, data analysis requirements, and the scope and utility of the characterization results obtained. This paper presents a global dynamic characterization program based on controlled impact dynamic testing that was applied to a truss bridge. The impact testing was performed using a hand-held impact hammer and a falling weight deflectometer (FWD) as dynamic excitation sources. The objective of the project was to evaluate if the FWD, which can produce a broadband dynamic force, can be effectively used as a tool for quantitatively characterizing the performance and condition of bridges. Many transportation agencies already use FWD devices for their pavement evaluation programs and it follows that if the device can be successfully used for impact dynamic testing of bridges, these agencies could their FWDs to also quantitatively evaluate their bridges. The paper discusses different dynamic testing approaches and presents an impact dynamic testing program executed for the truss bridge. The results obtained using the two dynamic excitation devices are presented and compared with each other, and with the results from an analytical model of the bridge. Finally, several observations and conclusions related to the efficacy of FWD devices for impact dynamic testing of bridges are presented and discussed.
  Authors: Fernstrom, Eric Victor; Carreiro, Jessica L.; Rawn, Jeremy D.; Grimmelsman, Kirk A.
  Authors: Fernstrom, Eric Victor; Carreiro, Jessica L.; Rawn, Jeremy D.; Grimmelsman, Kirk A.
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Design; Maintenance and Preservation
  Session: 525
  Paper Number: 13-5182
• Pedestrian Crash Risk on Boundary Roadways: University Campus Case Study
  Abstract: Prominent pedestrian trip attractors, such as college campuses and major urban parks, are often surrounded by roadways with high volumes of motor vehicle traffic. While many pedestrians cross busy boundary roadways, relatively little is known about pedestrian crash risk along these types of facilities. This study quantifies pedestrian crash risk at roadway intersections on the boundary of the University of California, Berkeley campus during typical spring and fall semester weekdays. Manual pedestrian counts were extrapolated using data from three automated counter locations to represent pedestrian exposure. Pedestrian crash risk was highest at intersections along the boundary roadways with the lowest pedestrian volumes. In addition, pedestrian risk in the evening (6 p.m. to midnight) was estimated to be more than three times higher than in the daytime (10 a.m. to 4 p.m.). The crash risk estimation approach presented in this paper can be used to study pedestrian safety on the boundary of campuses and other major attractors so that agencies can identify and prioritize engineering, education, and enforcement treatments to reduce pedestrian injuries.
  Authors: Schneider, Robert J.; Grembek, Offer; Braughton, Matthew
  Authors: Schneider, Robert J.; Grembek, Offer; Braughton, Matthew
  Year: 2013
  Document Type: Paper
  Subject: Design; Pedestrians and Bicyclists; Safety and Human Factors
  Session: 669
  Paper Number: 13-5204
• Comparative Analytical and Experimental Investigation of Pavement Hydroplaning-Predictive Methods
  Abstract: Hydroplaning risk reduction is one important consideration for safety in pavement network design and lane expansion, in particular. First, the authors performed an extensive study of all analytical methods that are available to predict water film thickness due to rain events and dynamic hydroplaning threshold speeds. Subsequently, field experiments were conducted in order to validate these existing methods of calculating such parameters. A rainfall simulator, which produces uniform, regulated rainfall, was used to quantify water buildup on an actual roadway segment. The results of the rain simulator experiment were consistent with models previously developed in the PAVDRN software, and by Gallaway and the New Zealand Roadway Laboratory. A locked wheel skid tester was used to detect the onset of dynamic hydroplaning by measuring friction loss under different speed and water film thickness scenarios. The results of the hydroplaning experiment were consistent with models previously developed in the PAVDRN software, and by the Texas Department of Transportation, and Ong and Fwa. These models give conservative estimates for hydroplaning-related parameters; therefore they are appropriate for use as highway design tools.
  Authors: Metz, John
  Authors: Metz, John
  Year: 2013
  Document Type: Paper
  Subject: Design; Pavements
  Session: 552
  Paper Number: 13-5216
• Decision Tool to Define and Quantify Interchange Complexity
  Abstract: Because complexity is typically a qualitative characteristic, the ability to objectively evaluate the complexity of an interchange is somewhat difficult. This difficulty is compounded when trying to compare the complex features of multiple interchanges. This paper discusses a spreadsheet-based decision tool developed as a method of quantifying and comparing the complexity of freeway interchanges in the United States. Initial discussion focuses on the steps that guided researchers in developing the spreadsheet, followed by a description of the spreadsheet itself and how practitioners can use it to evaluate the complexity of interchanges under their consideration. The paper also contains a review of the results researchers obtained from the spreadsheet in an evaluation of the complexity of 28 existing interchanges in 11 states; these study sites ranged from relatively simple to very complex, and results indicate that the spreadsheet generated scores that were generally consistent with researchers’ qualitative estimation of the sites’ relative complexity. The concluding section of the paper contains discussion on what the spreadsheet results mean and how they can be interpreted.
  Authors: Brewer, Marcus A.; Fitzpatrick, Kay; Chrysler, Susan T.
  Authors: Brewer, Marcus A.; Fitzpatrick, Kay; Chrysler, Susan T.
  Year: 2013
  Document Type: Paper
  Subject: Design
  Session: 679