2013 Subject Index: Operations and Traffic Management

• Operational and Safety Effects of Using Left-Turn Lanes with Substandard Lengths at Unsignalized Median Openings: Case Study in Houston, Texas
  Abstract: For median-divided roadways, the AASHTO Greenbook specifically encourages the use of left-turn lanes at median openings to eliminate stopping in through-traffic lanes. However, in urban areas, the Greenbook requirements for the lengths of median turn lanes often exceed the available length between two adjacent openings. Thus, left-turn lanes with substandard lengths have been in wide use at median openings on urban arterial roads. The objective of this study was to investigate whether it is operationally effective and safe to use median left-turn lanes of substandard lengths at unsignalized median openings. For this purpose, an analytical model was developed to estimate the delay incurred by left-turn vehicles as they decelerate in through-traffic lanes in preparation for the left-turn maneuvers. A case study was conducted on a 3,000-ft corridor on Jones Rd. in Houston, Texas, where eight median left-turn lanes have been installed, all with substandard lengths. Using calibrated micro-simulation models as benchmarks, the proposed model showed reasonable performance. Actual rear-end crashes and simulated rear-end conflicts generally revealed that such lanes did not result in compromised safety performance.
  Authors: Chen, Xiaoming; Qi, Yi; Liu, Guanqi; Wu, Jianing
  Authors: Chen, Xiaoming; Qi, Yi; Liu, Guanqi; Wu, Jianing
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Deploying Transportation Research-Doing Things Smarter, Better, Faster
  Session: 672
  Paper Number: 13-0071
• An improved approach for the sensitivity analysis of computationally expensive microscopic traffic models: a case study of the Zurich network in VISSIM
  Abstract: Microscopic traffic simulators are useful tools for designing, evaluating and optimizing transportation systems. In order for a simulator to accurately describe reality, the corresponding traffic model must be properly calibrated. However, the calibration can be rather difficult when the model is computationally expensive and has many parameters. To overcome these difficulties, Sensitivity Analysis (SA) can be applied as an essential instrument for supporting model calibration. Through SA the practitioners can obtain valuable information about the relationship between model inputs and outputs, and hence focus on the proper set of most influential parameters for the calibration. In this paper we developed an SA approach based on the Elementary Effects (EE) method. It screens the most influential parameters in a complex model through computing the corresponding EE and qualitatively comparing the Sensitivity Indexes. With the improved sampling strategy, this approach is much more efficient than the original EE method.A case study of the Zurich network in VISSIM is included here to illustrate the methodology of the proposed approach. The results demonstrate its efficiency and accuracy. In addition, they show that it can be a very useful tool for the SA of computationally expensive microscopic traffic models like VISSIM, as well as other complex models in the general scientific community.
  Authors: Ge, Qiao; Menendez, Monica
  Authors: Ge, Qiao; Menendez, Monica
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 769
  Paper Number: 13-0075
• Vehicle Routing Problem with Pickups, Deliveries, and Handling Costs
  Abstract: This paper proposes a novel and practical vehicle routing problem with pickups, deliveries and handling costs (VRPPD-H). The VRPPD-H extends the conventional vehicle routing problem with pickups and deliveries (VRPPD) by taking into account additional handling costs caused by loading and unloading operations for cargo rearrangement. Four mixed integer linear programming models are first built for the VRPPD-H under the four different cargo storage and handling policies. Two types of branch-and-cut exact algorithms are subsequently used to solve each of these four models. Finally, numerical experiments are carried out to assess the models and algorithms proposed in this study.
  Authors: Miao, Lixin; Meng, Qiang; Ruan, Qingfang
  Authors: Miao, Lixin; Meng, Qiang; Ruan, Qingfang
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-0082
• Macroscopic Fundamental Diagram for Urban Streets and Mixed Traffic: Cross-comparison of Estimation Methods
  Abstract: In the last decade, many paper focused on describing vehicular traffic stream of an arterial on an aggregate level. Unfortunately, among this considerable body of research, only few papers account for bus systems. Our paper tries to fill this gap by investigating two potential methods to estimate macroscopic fundamental diagrams of multimodal transport systems of a signalized arterial. The first approach models endogenously motion of bus by extending the work by the moving bottleneck theory, whereas the second approach proposes to incorporate exogenously effects of buses. The estimated macroscopic fundamental diagrams are then cross-compared to results provided by micro-simulation software that finely reproduce traffic stream. It turns out that mean speeds of vehicles and buses produced by the different methods are similar and consistent. Finally, results of the three methods are expressed in terms of levels of service and confronted with the levels of service of the HCM2010.
  Authors: Xie, Xiaoyan; Chiabaut, Nicolas; Leclercq, Ludovic
  Authors: Xie, Xiaoyan; Chiabaut, Nicolas; Leclercq, Ludovic
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 807
  Paper Number: 13-0105
• Multi-Objective Vehicle Routing Problems with Time Windows: a Vector Evaluated Artificial Bee Colony Approach
  Abstract: The vehicle routing problem with time windows, widely used in practice, is an NP-hard problem. The proposed optimization algorithm is based on the artificial bee colony algorithm combined with the vector evaluated technique for solving the problem as a multi-objective problem. Unlike traditional two-steps algorithms, this algorithm provides a simultaneous solution set. The approach was tested on standard Solomon benchmark problems and the result shows that this algorithm was better than or equal to other heuristic algorithms.
  Authors: Nahum, Oren E; Hadas, Yuval; Spiegel, Uriel
  Authors: Nahum, Oren E; Hadas, Yuval; Spiegel, Uriel
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-0106
• Measurement Bias and Reproducibility of In-Service Sign Retroreflectivity Readings Made with Handheld Instruments
  Abstract: With new requirements to maintain sign retroreflectivity, a number of agencies have selected maintenance programs that involve measuring retroreflectance of traffic signs. The accuracy and precision of handheld retroreflectometers, however, is not regulated, and the bias and reproducibility of handheld retroreflectometers needs to be assessed. This had, until now, not been done for instruments on in-service signs in field conditions.To assess the measurement bias and reproducibility of handheld retroreflectometers, readings of sign retroreflectance were taken during two periods separated by a 3-week interval, each time by two retroreflectometers. The average measurement bias was found to be 1.59 and 20.0 cd/lx/m2 for readings made on beaded and prismatic signs, respectively, and the reproducibility error was found to be 1.66 and 11.9 cd/lx/m2 for readings made on beaded and prismatic signs, respectively. When compared to the total retroreflectance of these signs, these average differences are relatively small. However, the amount of observed variability is enough to conclude that supplemental readings, whether by another instrument or at a different time, may produce markedly different values of retroreflectance.
  Authors: Brimley, Bradford; Carlson, Paul J.; Ye, Fan
  Authors: Brimley, Bradford; Carlson, Paul J.; Ye, Fan
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 805
  Paper Number: 13-0032
• Driving Simulator Evaluation of Effects of Nine Panel and Overflow Combination Specific Service Logo Signs on Driver Performance and Distraction
  Abstract: The North Carolina Department of Transportation has been experimenting with nine panel and overflow combination service logo signs at interchanges where the number of qualifying businesses providing a certain service exceeds the maximum of six business logo panels per sign. A concern some expressed with respect to nine panel signs is added driver distraction. The objective of this study was to use driving simulation to compare driver performance between nine panel, overflow combination, and six panel logo signs in specific service detection. Twenty-four participants were asked to search for a target food business logo panel as they drove in the simulator. The dependent variables measured included signal detection, response time, average speed, lane deviation, speeding percentage, off-road glance percentage, and maximum off-road glance duration. Based on results, it is suggested that highway agencies can use overflow combination or nine panel logo signs, where there are more than six qualifying businesses in a category at an interchange, without negative implications for driver performance.
  Authors: Hummer, Joseph E.; Rasdorf, William J.; Kaber, David B; Harris, Elizabeth Allison; Zhang, Yu; Rogers, Meghan; Hu, Jia
  Authors: Hummer, Joseph E.; Rasdorf, William J.; Kaber, David B; Harris, Elizabeth Allison; Zhang, Yu; Rogers, Meghan; Hu, Jia
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 429
  Paper Number: 13-0117
• Analysis of Probability of Missing an Overhead Sign due to Heavy-Vehicle-Induced Occlusion: Application to Sign Design
  Abstract: Traffic signs are an important means of communication with drivers on road. With the increase in multi-lane expressways the use of overhead signs has also increased. Like with sideway signs a driver can also miss an overhead sign due to occlusion of the sign by a leading heavy vehicle. Little or no research has been carried out to mathematically analyse conditions under which the driver of a light vehicle will not be able to read a sign due to a leading heavy vehicle. The lack of an analytical understanding of this phenomenon is reflected in the available design standards of the day. This paper analyses the conditions that lead to occlusion of overhead signs because of a leading heavy vehicle. Next, the duration for which the occlusion occurs is determined. Subsequently the results on duration of occlusion are used to evaluate whether enough time is left for the driver to read the sign. If enough time is not available then the driver is said to have “missed” the sign. The analysis indicates that there exists regions in the speed-density (u-k) space where a driver in the light vehicle will miss the sign. Assuming that the speeds of the light and heavy vehicles and the distance headway between them vary randomly, the probability of missing a sign is also obtained. This is used to determine a sign design (in terms of sign features and repetitions of the sign) which keeps the probability of missing the information on a sign below a threshold.
  Authors: Agarwal, Vivek; Chakroborty, Partha
  Authors: Agarwal, Vivek; Chakroborty, Partha
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-0126
• Mathematical Modeling Approach to Resource Allocation for Railroad-Highway Crossing Safety Upgrades
  Abstract: In this paper we propose a mathematical model for the resource allocation problem for railroad-highway crossing safety upgrades. The proposed approach is compared to existing methods for resource allocation safety upgrades. The comparison proves that the proposed mathematical modeling approach is more effective than currently used sorting methods.
  Authors: Konur, Dincer; Golias, Mihalis M.; Darks, Brandon
  Authors: Konur, Dincer; Golias, Mihalis M.; Darks, Brandon
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 518
  Paper Number: 13-0128
• Current State of Research on the Long-Term Deterioration of Traffic Signs
  Abstract: The minimum retroreflectivity standard for traffic signs in the Manual on Uniform Traffic Control Devices requires that transportation agencies replace signs when they deteriorate beyond a prescribed minimum level of retroreflectivity. There are many sheeting products available with a variety of initial retroreflectivity levels for agencies to choose from when they need to install signs, but one primary concern agencies may have is their expected life. This paper serves as a compilation of studies related to the long-term deterioration of traffic signs to present what research has been completed in this area. The research compiled here shows that some signs may have an unrealistically long expected lifespan, a conclusion resulting from limitations in the study designs and their assumptions. A controlled long-term study of the deterioration of traffic signs with respect to retroreflectivity and color is encouraged to provide agencies the information necessary to select appropriate traffic sign products.
  Authors: Brimley, Bradford; Carlson, Paul J.
  Authors: Brimley, Bradford; Carlson, Paul J.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 805
  Paper Number: 13-0033
• Development of Evaluation Criterion for Commercially Available Proximity Warning Systems to Prevent Backing Fatalities in Construction Work Zones
  Abstract: Various sensing technologies, such as radars, video cameras, and tag based systems, have been developed and tested to provide hazard warnings to operators in order to prevent collisions within blind areas of construction equipment. However, due to the various construction equipment characteristics, there is no panacea in terms of technology that will work for all types of construction equipment. Therefore, it is necessary to develop criteria for selecting proximity warning systems for specific equipment types. The main objectives of this study were: (1) to select construction equipment types which most frequently cause backing accidents in construction work zones; (2) to establish a generic proximity warning systems selection criteria for selected equipment types; and (3) to select appropriate proximity warning systems for selected vehicle types. From accident and blind area data analysis, pickup and dump trucks were selected for our test. In addition, the sensor selection criteria for both pickup and dump trucks were developed based on eight evaluation factors and criteria which were collected from related publications and specifications from commercially available systems. The selection criteria were validated by 20 external experts in the field of construction safety and sensing. As a result, three sensor systems for pickup trucks and one sensor system for dump trucks were selected based on the developed evaluation criteria.
  Authors: Choe, Soo Young; Leite, Fernanda; Seedah, Dan; Caldas, Carlos
  Authors: Choe, Soo Young; Leite, Fernanda; Seedah, Dan; Caldas, Carlos
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 400
  Paper Number: 13-0129
• Dynamic Programming Approach for Arterial Signal Optimization
  Abstract: Link Performance Functions (LPFs) are essential components of macroscopic models for signal optimization, traffic assignment or combined control-assignment models. Numerous studies have developed a variety of performance functions for signal optimization. Most of these studies attempted to use simplified LPFs that do not capture the important relationships and dependencies among the variables. In this paper we introduce dependent link performance functions (DLPF), where the performance on any link depends not only on the flow pattern on that link alone, but also on the flow patterns on the feeder links. Such functions represent with greater fidelity the performance characteristics of the link and can lead to better control, assignment, etc. We then present an optimization model that explicitly considers flow interactions among successive links and applies it in a dynamic programming procedure to determine optimal signal settings. The procedure is an offshoot of the Combination Method for offset optimization. The procedure is illustrated for an arterial street and demonstrates its efficacy in comparison with existing optimization models.
  Authors: Gartner, Nathan H.; Deshpande, Rahul
  Authors: Gartner, Nathan H.; Deshpande, Rahul
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-0177
• 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
• Safety and Operational Benefits of Variable Speed Limit Under Different Traffic Conditions and Driver Compliance Levels
  Abstract: Control of traffic by Variable Speed Limit (VSL) has been researched for a long time but there is lack of consensus on the safety and operational benefits of VSL and on the impact of driver compliance. The objective of this paper is to provide quantitative evaluations of these benefits and show the importance of driver compliance to VSL which ultimately narrows down the lack of consensus. Combination of VISSIM and Surrogate Safety Assessment Model (SSAM) was used in the study. SSAM analyzes the trajectories of simulated vehicles and detect possible conflicts along their journey. To support the safety analysis of this study, an attempt was done to correlate the simulated vehicle conflicts with historic crashes. Three scenarios of traffic conditions were considered, namely: 1) heavily congested, 2) lightly congested, and 3) non-congested. Each scenario is further examined under four driver compliance levels, including: 1) low compliance, 2) medium compliance, 3) high compliance, and 4) very high compliance. The results confirmed that VSL has safety and operational benefits on motorway traffic. VSL has the highest safety benefits during highly congested traffic conditions followed by lightly congested and least during non-congested conditions. Moreover, the system has the highest operational benefits during lightly congested traffic conditions, little during non-congested and no benefit during heavily congested conditions. It was also found that the safety benefits of VSL are not at the expenses of increase in travel time. However, these benefits showed significant variations depending on the level of compliance to the system. The study concludes that the success of VSL is highly dependent on the level of driver compliance.
  Authors: Habtemichael, Filmon; Picado-Santos, Luis Guilherme
  Authors: Habtemichael, Filmon; Picado-Santos, Luis Guilherme
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 438
  Paper Number: 13-0138
• Impact Assessment of Adaptive Cruise Control and Forward Collision Warning Within Field Operational Test in Europe
  Abstract: The euroFOT project is the first large-scale Field Operational Test (FOT) of multiple Advanced Driver Assistance Systems (ADAS) in Europe. It will evaluate the impacts of ADAS on safety, traffic efficiency, environment, driver behaviour and user-acceptance in real life situations with normal drivers, by means of collected data from instrumented vehicles. By offering valuable information for the short- and long-term impact of ADAS the euroFOT project aims to encourage the deployment of ADAS. Altogether, about 1000 vehicles from different manufacturers and with different advanced driver assistance systems will take part in the FOT. The euroFOT fleet is coordinated by five Vehicle Management Centers (VMC).The Institute of Automotive Engineering (ika) of the RWTH Aachen University analysed the effects of ACC usage in combination with FCW under normal driving conditions of 100 passenger cars. The results of the data analysis show positive effects on traffic safety and fuel consumption. In addition, the complete process chain from the data collection to the analysis was defined and conducted at the ika.
  Authors: Benmimoun, Mohamed; Pütz, Andreas; Zlocki, Adrian; Eckstein, Lutz
  Authors: Benmimoun, Mohamed; Pütz, Andreas; Zlocki, Adrian; Eckstein, Lutz
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 303
  Paper Number: 13-0195
• Incorporating Weather Effects in Highway Capacity Manual Reliability Analysis
  Abstract: This study details a methodology for incorporating weather effects in an HCM-based Freeway Reliability analysis. The methodology is capable of estimating historical weather probabilities as well as predicting future year weather probabilities by weather condition from a 10 year historical average probability database. Probabilities for historical analyses are directly calculated from detailed hourly weather reports for the period of time that freeway reliability is reported. The methodology is applied for the 101 largest metropolitan areas in the US to create a probability database for use in a probabilistic scenario generator to incorporate non-recurring effects in HCM freeway operations analysis.In addition to presenting the methodology, sample results are validated at four locations. Probabilities of each weather type are shown with a confidence interval based on the variability of probabilities by year within the 10 year sample. Finally, prediction errors are calculated with multiple sample sizes. The results show that prediction errors stabilize near the 10 year sample size.
  Authors: Chase, R. Thomas; Hajbabaie, Ali; Schroeder, Bastian J.
  Authors: Chase, R. Thomas; Hajbabaie, Ali; Schroeder, Bastian J.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 313
  Paper Number: 13-0227
• Modeling Driver Behavior at Signalized Intersections in India
  Abstract: Safety at signalized intersection depends on a number of factors, among which human behaviour is the sole significant factor that is unpredictable. No serious attempts have been made to collect and analyse the driver behaviour data in Indian conditions. While a few researchers have tried to analyse the driver behaviour during the onset of yellow phase, some potentially significant factors in an heterogeneous traffic conditions have not yet been studied. No literature was available for the analysis of driver behaviour during the green and red phase. There comes the need for the present study for analysing the driver behaviour on all the three phases of the signal. This study is aimed at modelling the behaviour of drivers at few urban signalized intersections in India during yellow phase, red phase and green phase. A binomial logistic regression model was developed for the drivers’ stopping behaviour during yellow phase. The result shows that yellow-onset distance from stop line, yellow-onset speed, vehicle type and age of the driver are statistically significant factors that influence the drivers’ stopping behaviour. A multinomial logit model was developed to represent the vehicle accumulation pattern during the red phase and it was found that type of vehicle, time of arrival and the position of vehicles are all statistically significant factors. Lane changing behaviour during green phase was also modelled relating the type of vehicle, distance to intersection, the speed of the subject vehicle and the relative speed between the subject vehicle and the lead vehicle.
  Authors: Alex, Sheela; Isaac, Kuncheria P.; Varghese, Vincy
  Authors: Alex, Sheela; Isaac, Kuncheria P.; Varghese, Vincy
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-0257
• Traffic Signal Timing Optimization: Choosing the Objective Function
  Abstract: Choosing an appropriate objective function in optimizing traffic signals in urban transportation network is not a simple and straightforward task because it most likely would affect the set of constraints, modeling variables, outputs obtained, and computer and human resources needed. In this study we develop a methodology for selecting the appropriate objective function for the signal timing optimization problem, and apply it to a realistic case study network under four different demand patterns (symmetric/asymmetric undersaturated/oversaturated). The selection is made from five candidates: delay minimization, travel time minimization, throughput-minus-queue maximization, maximizing the number of completed trips (or trip maximization), and maximizing the weighted number of completed trips (or weighted trip maximization). Findings indicated that for all demand patterns, weighted trip maximization improved network performance compared to the other objective functions. It reduced system total delay by 0.1% to 5.2% in symmetric undersaturated demand, by 1.0% to 2.4% in asymmetric undersaturated demand, by 1.2% to 16.6% in symmetric oversaturated demand, and by 11.7% to 27.4% in asymmetric partially oversaturated demand. These figures indicate that the weighted trip maximization objective function is most suitable among the candidate for oversaturated conditions especially when demand is not symmetric. Throughput-minus-queue and trips maximization objective functions were the second most suitable objective functions for oversaturated conditions where trip maximization was slightly more suitable when demand was asymmetric.
  Authors: Hajbabaie, Ali; Benekohal, Rahim F.
  Authors: Hajbabaie, Ali; Benekohal, Rahim F.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-0261
• Empirical Evacuation Response Curve During Hurricane Irene in Cape May County, New Jersey
  Abstract: Understanding evacuation response behavior is critical for public officials in deciding when to issue emergency evacuation orders during an impending hurricane. Such behavior is typically measured by an evacuation response curve that represents the proportion of total evacuation demand over time during evacuation. This study analyzes evacuation behavior and constructs the evacuation response curve based on traffic data collected during Hurricane Irene (2011) in Cape May County, New Jersey. The evacuation response curve follows a general S-shape with sharp upward changes in slope following the issuance of mandatory evacuation notices. The sharp upward changes in slope represent quick response behavior, which may be in part caused by an easily mobilized tourist population, lack of hurricane evacuation experience, and/or the nature of the location, which in this case is a rural area with limited evacuation routes. Moreover, the widely used S-curves with different mathematical functions and state-of-art behavior models are calibrated and compared with empirical data. The results show that the calibrated S-curves with Logit and Rayleigh functions fit better with empirical data. The evacuation behavior analysis and calibrated evacuation response models based on this recent Hurricane evacuation event may benefit evacuation planning in similar areas. In addition, traffic data used in this study may also be valuable for the comparative analysis of traffic patterns between the evacuation periods and regular weekdays/weekends.
  Authors: Li, Jian; Ozbay, Kaan; Bartin, Bekir; Iyer, Shrisan; Carnegie, Jon
  Authors: Li, Jian; Ozbay, Kaan; Bartin, Bekir; Iyer, Shrisan; Carnegie, Jon
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 772
  Paper Number: 13-0285
• Analysis of pedestrian-vehicle traffic conflicts in street designs with elements of shared space
  Abstract: This paper investigates changes in pedestrian-vehicle traffic conflicts in urban streets redesigned according to the principles of shared space, using a recently developed Pedestrian-Vehicle Conflicts Analysis (PVCA) method. In a first step, the PVCA method is revised to more accurately reflect the features of shared space: this includes the definition of a systematic process for identifying conflict occurrences on one hand, and the full quantification of the conflict severity grading process on the other. Then, the refined PVCA method is applied to a case study in London, using video data from periods before and after the redevelopment of the Exhibition Road site from a conventional dual carriageway to a modern design with some elements of shared space. The results of the comparative analysis carried out indicate a general decrease in traffic conflict rates as a result of the redesign, but also highlight specific issues that may require additional analysis.
  Authors: Kaparias, Ioannis; Bell, Michael G.H.; Dong, Weili; Sastrawinata, Aditya; Singh, Amritpal; Wang, Xuxi; Mount, Bill
  Authors: Kaparias, Ioannis; Bell, Michael G.H.; Dong, Weili; Sastrawinata, Aditya; Singh, Amritpal; Wang, Xuxi; Mount, Bill
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Pedestrians and Bicyclists; Deploying Transportation Research-Doing Things Smarter, Better, Faster
  Session: 700
  Paper Number: 13-0309
• SURTRAC: Scalable Urban Traffic Control
  Abstract: This paper defines and evaluates a pilot implementation of a recently developed approach to real-time, adaptive traffic signal control. The pilot system, which is called SURTRAC (Scalable Urban Traffic Control), integrates concepts from traffic control theory with recent work in the field of multi-agent planning and has several important distinguishing characteristics. First, to promote scalability and reliability, SURTRAC operates in a totally decentralized manner; each intersection independently and asynchronously allocates its green time, based on current incoming vehicle flows. Second, SURTRAC aims at managing urban (grid-like) road networks with multiple (competing) traffic flows; network-level coordination is accomplished by communicating projected outflows to downstream neighbors, which gives these intersections a more informed basis for locally balancing competing inflows while simultaneously promoting establishment of larger "green corridors". Third, SURTRAC truly operates in real-time; each intersection recomputes its allocation plan and re-communicates projected outflows every 1-2 seconds in rolling horizon fashion, enabling both effective operation in tightly spaced signal networks and responsiveness to sudden changes in traffic conditions. After describing our basic approach to adaptive traffic signal control and the pilot implementation of SURTRAC, we present the results of a field test conducted on a nine-intersection road network in the East Liberty section of Pittsburgh, Pennsylvania. In this pilot test, SURTRAC is seen to achieve major reductions in travel times and vehicle emissions over pre-existing signal control.
  Authors: Smith, Stephen F.; Barlow, Gregory J.; Xie, Xiao-Feng; Rubinstein, Zachary B.
  Authors: Smith, Stephen F.; Barlow, Gregory J.; Xie, Xiao-Feng; Rubinstein, Zachary B.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-0315
• Developing a Comprehensive Sustainable Transportation Analysis Framework
  Abstract: As climate change has become understood and accepted by state, regional and local governments, there has been a growing impetus to set goals and targets for reduction of greenhouse gas emissions and use of fossil fuels. Tools to prioritize and implement regional and local transportation sector emissions reduction policies have been unavailable to practitioners and policy makers. At the same time, the transportation industry is undergoing a paradigm shift from mobility to access, requiring new ways of defining and evaluating success. Furthermore, transportation agencies are under pressure to deliver projects in a safer, more equitable and cost effective manner. To fill this void, a grass roots group of transportation and sustainability professionals formed to develop a rating system and the planning tools needed to make measurable headway toward improving the performance of transportation in all these areas. Since 2009 the Sustainable Transportation Analysis and Rating System (STARS) has been under development and is being tested on both transportation projects and regional plans. This paper identifies characteristics of STARS that advance the state of the practice while highlighting challenges and gaps. STARS provides a suite of credits incorporating tools and guidance based upon triple bottom line principles. Backcasting is used to establish desired future outcomes, rather than the more traditional forecasting process. STARS uses performance measures to analyze all transport modes and strategies. A pilot project in Santa Cruz County, California is highlighted. Performance monitoring will determine whether the system changes practices and outcomes.
  Authors: Dondero, George A; Hurley, Peter
  Authors: Dondero, George A; Hurley, Peter
  Year: 2013
  Document Type: Paper
  Subject: Construction; Environment; Operations and Traffic Management
  Session: 274
  Paper Number: 13-0348
• 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
• Impact of Ramp and Mainline Flow Mix on Freeway Breakdown and Capacity Characteristics
  Abstract: This study examined how the mix between ramp and mainline flows influences breakdown and capacity characteristics such as: pre-breakdown flow (PBDF), queue discharge flow (QDF), queue discharge speed (QDS), breakdown duration (BDD), and capacity change after breakdown. The mix between ramp and mainline flow was represented using the Ramp Volume Ratio (RVR) which is defined as the percentage that the ramp flow is of the total merge area traffic flow. The research also examined how results may alter if the analysis adopts the plain Ramp Volume (RV) itself, as a flow mix index, instead of the RVR. Four freeway bottlenecks in Milwaukee freeway system were used in the analysis. Because merge areas can have different utilization levels or congestion intensities, bottlenecks were ranked based on the utilization of the merge influence area and treated distinctly. For bottlenecks with heavily-utilized merge-areas, both capacities (PBDF and QDF) were reduced when RVR increased. Interestingly, BDD appeared to be very sensitive to RVR. BDD was found to double, triple or almost quadruple when ramp flow comprised a higher percentage of mainline flow. For bottlenecks with moderately-utilized merge-areas, results were usually different and counter-intuitive. For some cases, increasing the RVR resulted in a capacity flow increase and BDD decrease. The adoption of the RV index instead of the RVR index altered or reversed many results and trends for all bottlenecks. The study explains the difference between RVR and RV, demonstrates the impact of merge-area utilization, and provides further recommendations.
  Authors: Dehman, Amjad; Drakopoulos, Alexander
  Authors: Dehman, Amjad; Drakopoulos, Alexander
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-0388
• Toward Smart Intersections for Urban Travelers on Sustainable Modes:Better Service via Real-Time Sensing
  Abstract: Sustainability has emerged as a social goal for transportation to pursue by making a change, and transpor-tation engineering should be aimed to increase the level of walking and pedalcycling travels to advocate “New Urbanism and Smart Growth”. More walkable communities are believed more beneficial to the moving public and the sustainability of multimodal transportation systems. Walking and pedalcycling modes promote healthy living style and possess sustainable advantages over the motorized modes in man-ifold aspects. Moreover, the increase in walking and pedalcycling travels fosters the ridership level of public transportation systems. Hence, to boost advancements in pedestrian-/pedalcycle-related infrastruc-ture is essential to bettering transportation sustainability in real-world practice.This research innovatively realized a system prototype which improves non-motorized traveler service at typical urban intersections, in order to resolve the problem that the existing signal timing stand-ard cannot offer friendly accommodation and adequate safety for waiting and crossing pedestrians and/or pedalcyclists. The new system resorts to the real-time sensing concept to smartly adjust signal displays to ensure that waiting pedestrians and/or pedalcyclists are released in a responsive manner and crossing ones are safely protected by signals. In simulation tests, this research quantified the benefits from the new sys-tem in comparison with its original counterpart. Simulation experiments unveiled a current timing safety countermeasure is deficient for mobility efficiency. In contrast, the new functions smartly serves for all non-motorized travelers with friendly accommodation and adequate safety, while maintaining good mobility efficiency for motorized travelers.
  Authors: Lu, George; Noyce, David A.
  Authors: Lu, George; Noyce, David A.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0478
• Evaluation of InSync Adaptive Traffic Signal Control in Microsimulation Environment
  Abstract: InSync, an ATCS developed and supported by Rhythm Engineering, is one of the youngest ATCSs on the market. Yet, dozens of InSync systems were recently deployed around the country. InSync has been evaluated in microsimulation before. However, previous attempts lacked: a rigor of scientific approach, effort to carefully build a field-like microsimulation model, and analysis that investigates a comprehensive set of performance measures including environmental and safety metrics. This study addresses these issues by evaluating performance of InSync on segment of SR 421 - a 12-intersection corridor in Volusia County, FL. InSync adaptive traffic control logic has been compared to three conventional Time-Of-Day signal timings plans in a virtual reality of microsimulation model. VISSIM model of SR 421 was carefully calibrated and validated to resemble field conditions as much as possible. Each of scenarios was simulated multiple times and results were tested for statistical significance. Findings show that InSync outperforms TOD signal timings in terms of traffic efficiency. Savings vary between 2-20% depending on a particular performance measure and time of the day. In terms of environmental factors and surrogate safety measures InSync also outperforms TOD signal timings but sometimes it pays the price of enabling more efficient traffic operations than the TOD plans. Further research is necessary to investigate InSync benefits in the environment of volatile changes in traffic flows.
  Authors: Stevanovic, Aleksandar; Zlatkovic, Milan
  Authors: Stevanovic, Aleksandar; Zlatkovic, Milan
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0487
• Free-Flow Speed Model Based on Portuguese Roadway Design Features for Two-Lane Highways
  Abstract: Speed is a key performance measure in economic and environmental analyses of two-lane highways. Speed, combined with the percent time-spent-following, is also used in the assessment of level of service. Under free-flow conditions, the circulation of a given vehicle is not constrained by the presence of other vehicles, and the driver’s speed choice reflects his response to the geometric features of the road and roadside interference, as well as his perception of risk. Many studies concerned with the effects of road characteristics, design features in particular, on vehicle speed, have been conducted in several countries in recent decades, providing useful tools for modeling speed and evaluating alignment consistency.This paper presents an exponential free-flow speed model, applicable to both curves and tangents, that was developed for two-lane highways in Portugal. The variables included in the model are representative not only of the road element under consideration (curve or tangent) but also of the preceding road section and of the visual field downstream from the element. The results from this model are compared with other authors’ results and with the guidelines in the Highway Capacity Manual 2010. In addition to the primary influence of the horizontal curvature on speed, the results show that other factors, such as the cross-sectional width, the density of access points and the downstream visibility, are also important.
  Authors: Lobo, António; Rodrigues, Carlos; Couto, António Fidalgo
  Authors: Lobo, António; Rodrigues, Carlos; Couto, António Fidalgo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 405
  Paper Number: 13-0512
• Effects of Flashing Yellow Arrow Signal Displays on Driver Comprehension and Operations
  Abstract: In the spring of 2010, the Illinois Department of Transportation initiated an area-wide implementation of the flashing yellow arrow (FYA) as the display for the left-turn permissive interval at over 100 intersections operating with protected/permissive left-turn (PPLT) control in the Peoria, Illinois area. The authors of this paper conducted research to evaluate the effectiveness of FYAs on driver comprehension and traffic operations. A total of 363 drivers completed an online static survey that included seven left-turn scenarios which portrayed the protected and permissive indications of PPLT phasing, with the flashing modes being animated. The results of the survey indicated that drivers had a high comprehension of both the circular green (CG) and FYA permissive left-turn indications. However, the survey results provided evidence of some drivers misinterpreting the meaning of a permissive left-turn with CG display and incorrectly and unsafely interpret the meaning as “go” under some circumstances. With supplemental traffic signs present, driver understanding of the correct action to take when confronted with a FYA significantly increased, and the percentage of fail-critical, incorrect “go” responses significantly decreased. Before and after field observations including 128 hours of data collected at 16 study approaches were collected and the following variables were investigated: critical gap, left-turn red light running and yellow light running, and traffic conflicts. Overall, the findings of this study suggest that drivers in the Peoria, Illinois area had high comprehension and acceptance of the FYA message. Additionally, the FYA did not appear to have any negative impacts on traffic operations.
  Authors: Schattler, Kerrie L.; Lund, Jessica A.; Lorton, William B.; Burdett, Beau
  Authors: Schattler, Kerrie L.; Lund, Jessica A.; Lorton, William B.; Burdett, Beau
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-0529
• Urban Traffic Information System for Intelligent Transportation System Applications
  Abstract: Travel speed is an important parameter in the measurement of road traffic. In this paper, Urban Traffic Information System (UTIS) has been proposed as a mobile detector for measuring link travel speeds. However, UTIS incurs missing data, such as those caused by construction, detector failures, communication failures, and other factors. This paper describes an imputation model that uses the multiple regression to accurately estimate average roadway link travel speeds. The model predicts link travel speeds using a robust data imputation method based on available information for neighbor links and the adjacent time periods. A field test showed that the variance of the percent errors of link travel speeds was reduced when they were measured using the new model. Therefore, it can be concluded that the proposed model significantly improves the accuracy of travel speed measurement.
  Authors: Ki, Yong-Kul; Bae, Gwang-soo; Kim, Eun-Jeong; Ahn, Gye-Hyeong
  Authors: Ki, Yong-Kul; Bae, Gwang-soo; Kim, Eun-Jeong; Ahn, Gye-Hyeong
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-0539
• PROBE VEHICLE BASED STATEWIDE MOBILITY PERFORMANCE MEASURES FOR DECISION MAKERS
  Abstract: Decision makers in state transportation agencies typically manage budgets approaching or exceeding $1B. However, the data they have historically used for making investment decisions is quite coarse and is typically based upon short-term volume counts fed into models to forecast future performance. As a result, it is not uncommon for construction projects to address needs that were forecast to be a priority five to ten years prior, while more pressing congestion challenges go unmet. This fact does not go unnoticed by the public and media, and it is essential that long-term planning begin to be supplemented by more current performance measures. Emerging private sector probe vehicle data obtained from mobile phones and commercial telemetric providers offers an opportunity to augment traditional forward-looking planning models with performance measures that reflect conditions motorists are experiencing today. This paper proposes analytical probe data reduction techniques that can be scaled to a project, region, state, or national level to create technically sound yet intuitive mobility performance measures of current freeway conditions. These types of performance measures are increasingly used by high-level agency management to identify locations where customers experience congestion, to determine the magnitude of congestion, and to compare congestion on various highway corridors. These proposed performance measures can be used for policy-oriented decisions such as prioritization of capital program investments, managing snow removal, and scheduling lane closures. In addition to the analytical data reduction, corresponding data visualizations of the performance measures are presented. This paper describes the application of these analytical techniques to seven Indiana interstates comprised of 1886 directional miles. These interstates span rural and urban sections that experience varying levels of recurring and non-recurring congestion due to special events, winter weather, and construction activity. Specific examples adjacent to the Indianapolis, Indiana; Louisville, Kentucky; and Chicago, Illinois, metro areas are presented along with the Top 10 congested Interstate segments.
  Authors: Brennan, Thomas M.; Remias, Stephen Matthew; Grimmer, Gannon; Horton, Deborah K.; Cox, Edward D; Bullock, Darcy M.
  Authors: Brennan, Thomas M.; Remias, Stephen Matthew; Grimmer, Gannon; Horton, Deborah K.; Cox, Edward D; Bullock, Darcy M.
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Policy
  Session: A0030T
  Paper Number: 13-0551
• Sensitivity Analysis-Based Heuristic Method for Transportation Network Capacity Model
  Abstract: The transportation network capacity is used to measure the maximum traffic flow that the network can serve. The commonly accepted transportation network capacity model considers the future demand increases in a variable trip distribution, of which the behavior is modeled using the equilibrium trip distribution and assignment model with variable destination costs (ETDA-VDC). Based on this, a sensitivity based heuristic algorithm is presented to solve the network capacity problem, which is formulated as a bi-level programming problem. The ETDA-VDC model in its lower level is solved using a modified network representation, on which the origin based algorithm is used to obtain the solution and the set of the minimum cost routes. The latest technique of sensitivity analysis for the ETDA-VDC model is employed to produce the derivatives required to implement the heuristic method. Numerical computations are demonstrated on a simple example and the Sioux Falls network. In such scale of problems, the performance of the algorithm is promising producing solutions that converge to the optimal solution regardless of the starting point.
  Authors: Du, Muqing; Cheng, Lin; Rakha, Hesham
  Authors: Du, Muqing; Cheng, Lin; Rakha, Hesham
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0557
• Using Time-Based Metrics to Compare Crash Risk Across Modes and Locations
  Abstract: The objective of this work is to identify better metrics of exposure when comparing traffic crash risk across modes or across locations. We propose that total time travelled should be used for road user exposure to crash risk. The idea behind this is that travel time reflects the differences in speeds across different modes and hence should be used as the basic exposure metric from which crash risk based on other metrics, such as travel distance, can easily be derived. We also propose that when comparing crash risk of different modes across different locations the time based mode share should be used as an explanatory variable. By using mode share we are generalizing the safety in numbers concept which focuses on absolute numbers. This work presents a discussion on why these two metrics were chosen and how they are different from the commonly used metrics. Quantitative evidence for the choice of time based metrics is also presented using travel survey data to compare crash risk across modes and locations.
  Authors: Guler, Sukran Ilgin; Grembek, Offer; Ragland, David R.
  Authors: Guler, Sukran Ilgin; Grembek, Offer; Ragland, David R.
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-0522
• Impact of Traffic Dynamics on Macroscopic Fundamental Diagram
  Abstract: Literature shows that – under specific conditions – the macroscopic fundamental diagram (MFD) describes a crisp relationship between the average flow (production) and the average density in an entire network. The limiting condition is that traffic conditions must be homogeneous over the whole network. Recent works describe hysteresis effects: systematic deviations from the MFD as result of loading and unloading.This article proposes a two dimensional generalization of the MFD, the so-called GeneralizedMacroscopic Fundamental Diagram (GMFD), which relates the average flow to both the average density and the (spatial) inhomogeneity of density. The most important contribution is that we show this is a continuous function. Using this function, we can describe the mentioned hysteresis patterns. The underlying traffic phenomenon explaining the two dimensional surface described by the GMFD is that congestion concentrates (and subsequently spreads out) around the bottlenecks that oversaturate first. We call this the nucleation effect. Due to this effect, the network flow is not constant for a fixed number of vehicles as predicted by the MFD, but decreases due to local queuing and spill back processes around the congestion ”nuclei”. During this build up of congestion, the production hence decreases, which gives the hysteresis effects.
  Authors: Knoop, Victor L.; Hoogendoorn, Serge; Van Lint, Hans
  Authors: Knoop, Victor L.; Hoogendoorn, Serge; Van Lint, Hans
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0595
• Dynamic Modeling of VISSIM Critical Gap Parameter at Unsignalized Intersections
  Abstract: Critical gaps are essential parameters in the modeling of traffic operations at unsignalized intersections and roundabouts, and they are main determinants in the calculation of intersection capacities. In microscopic simulation tools, they are basic vehicle-related variables, and their values and variations among the population are user-defined. Errors or oversimplifications of these basic variables may yield unrealistic results in terms of total throughput, queue lengths, waiting times, etc.In this study we propose a method to calibrate the critical gap parameter in microscopic simulations based on individual travel time observations, and a simple formulation for the calculation of critical gap parameters that takes into account the increasing risk taken by drivers on the minor street with increasing volumes on the major road. This new formulation allows a better match between accepted gaps observed in reality and the actual traffic conditions. The new methodology and model formulation have been used for calibration and validation of the minimum gap parameter of the software program VISSIM using data taken from several unsignalized intersections in the city of Leuven, Belgium. The results show clear outperformance of the volume-dependent model with respect to the conventional constant critical gap parameters.
  Authors: Viti, Francesco; Wolput, Bart; Tampere, Chris; Vandervelden, Pieter
  Authors: Viti, Francesco; Wolput, Bart; Tampere, Chris; Vandervelden, Pieter
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-0597
• Spatial and Temporal Correlation of Freeway Link Speeds: Empirical Study
  Abstract: Traffic variables are known to be correlated over time and space due to traffic flow propagation. However, the correlation pattern is still largely unknown and most of the research in short-term travel time prediction, demand forecasting, and network modeling either ignore or assume correlation. We aim to investigate the patterns of spatial and temporal correlations of average point speeds in a freeway setting. 5-minute speed aggregates are obtained for two directions of an urban freeway along a 12.0 mile segment. Other variables include traffic flow, ramp locations, number of lanes and the level of congestion at each detector station. Weighted least squares multivariate linear regression models are fitted to the data from 3 different times of day (morning, midday, and afternoon) along a shorter, 6.5 mile stretch of I-10 E freeway. The remaining stretch of I-10 E as well as the stretch of I-10 W are both used for cross-validation. Estimated regression models indicate that increasing spatial and temporal distances reduces the expected value of Fisher Z (transformed correlation). The positive parameters of spatial and temporal distance interaction term show that the reduction rate diminishes with spatial or temporal distance. Higher congestion tends to preserve higher correlation; variations in road geometry carry relatively small corrections to the models. Cross-validation results show that models are able to retain 75% or more of their original predictive capability on independent samples. The developed regression models are thus transferable and are apt to predict correlation on other freeway locations.
  Authors: Rachtan, Piotr; Huang, He; Gao, Song
  Authors: Rachtan, Piotr; Huang, He; Gao, Song
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0598
• Developing Algorithms for Real-Time Delay Estimation atSignalized Intersections Using Vehicle Arrival and Departure Times
  Abstract: Currently there are several methods to measure the performance of signalized intersections, but the capabilities of these methods to dynamically estimate vehicle delay are limited. Therefore, two delay estimation algorithms that use arriving and departure times of vehicles recorded at upstream and downstream sensors placed in the study zone were developed, using Microsoft Excel and Visual Basic. The algorithms were tested using VISSIM simulation software to simulate different lane configurations and gather “ground truth” data. The lane configurations tested were through-only lanes, through lanes with a midblock driveway, and through lanes with a turning bay. Different levels of volumes were simulated for each of the lane configurations. The through-only configuration showed excellent results, with maximum errors less than 3 seconds per vehicle for each test. The through lanes with midblock driveways were evaluated using added detection or no detection at the driveway. Results using the driveway sensors had 93 percent of the calculated average delays with less than 5 seconds per vehicle of error. Without the driveway sensors 84 percent of the calculated average delays were with less than 5 seconds of error. Results for the turning bay configuration had 94 percent of the calculated turning bay results with less than 5 seconds per vehicle of error.
  Authors: Forbush, Taylor R.; Saito, Mitsuru
  Authors: Forbush, Taylor R.; Saito, Mitsuru
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0599
• Comparing Calibrated Shared Space Simulation Model with Real-Life Data
  Abstract: Shared spaces are being implemented in many countries to deal with safety concerns and traffic flow problems in busy urban streets and street crossings. However shared space concepts could not be tested before being build so far due to the lack of a functioning traffic simulation that was able to incorporate social interactions between different transportation modes rather than following a purely rule based approach. The calibration of such a microscopic traffic simulation model using real world data from two shared space sites is presented in this paper. Furthermore, it is shown that the simulation can reproduce real life shared space behavior by comparing it to trajectory and interaction data collected at an implemented shared space project in Austria.
  Authors: Rudloff, Christian; Schönauer, Robert; Fellendorf, Martin
  Authors: Rudloff, Christian; Schönauer, Robert; Fellendorf, Martin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 828
  Paper Number: 13-0616
• Estimating the Impacts of Police Traffic Enforcement Stops on Freeway Operations and Capacity
  Abstract: Over the years, some police agencies have sought to be good stewards of urban traffic flow by reducing their emergency lights while on roadside enforcement stops, particularly during rush hour. In just over the last decade however, move over laws have been implemented in every state except Hawaii. These laws create a mandate for motorists to vacate the lane adjacent to the stopped emergency vehicle. Consequently, the traffic impacts of the police enforcement stop have shifted from a distraction that might slow traffic, to a mandate for drivers’ to change lanes or slow down.From a highway capacity standpoint, the enforcement stop can be modeled as a theoretical lane blocking event, adjusted for motorists’ move over compliance. This research examined 13,416 enforcement stops conducted near roadway traffic detectors on Florida freeways. Based on this research, police enforcement stops reduce available capacity between 54 and 58 percent on two-lane freeways, 35 and 41 percent on three lane facilities, 23 and 30 percent on four lane facilities, and 14 and 22 percent where five lanes are present. Regression analysis examined factors to explain the speed of vehicles passing stops and showed that the number of lanes, posted speed limit, and ambient lighting conditions were all statistically significant issues.From a policy standpoint, police should consider using their emergency lighting equipment throughout the duration of enforcement stops since they improve move over compliance and ostensibly safety. Though not modeled implicitly, breakdown is likely not a deterministic measure, so police activity during periods of high traffic flow and congestion should be reserved for compelling traffic safety needs.
  Authors: Carrick, Grady; Washburn, Scott S.
  Authors: Carrick, Grady; Washburn, Scott S.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 572
  Paper Number: 13-0631
• Paralleling Influence of Unscheduled and Scheduled Roadwork Characteristics on Traffic Incident Durations
  Abstract: The review of incident data covering freeways in Tennessee shows that approximately 2% of incidents each year are the result of unscheduled roadworks. While the public is always informed about the scheduled roadworks, most of unscheduled roadworks are initially unknown to the road users in general. The impact of unscheduled roadworks to traffic operations and safety are currently not well documented in the literature. While the literature review found many studies related to work zones, very few are focused specifically on unscheduled roadwork incidents. The objective of this study was therefore, to evaluate and compare the impact of unscheduled and scheduled roadworks to the length of incident durations. Both descriptive statistics and statistical modeling utilizing Generalized Ordered Logit Model (GOLM) and Multinomial Logit Model (MNL) were used. The GOLM model was used due to its less restrictive ability in estimation compared to parallel line models like ordinary ordered logit since it does not ignore the category ordering unlike MNL. Among the factors found to impact the incident durations significantly include, number of lanes closed, the type of lane closed, vehicle involvement, queue formation, means of incident notification, day of the week and the time of the day. There were slight variations in the magnitude of variable coefficients between scheduled and unscheduled models but with relatively same signs among these two. Comparing GOLM and MNL, signs of most variable coefficients were almost identical between the models but with different interpretations.
  Authors: Chimba, Deo; Kutela, Boniphace; Kwigizile, Valerian; Sando, Thobias
  Authors: Chimba, Deo; Kutela, Boniphace; Kwigizile, Valerian; Sando, Thobias
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 400
  Paper Number: 13-0637
• Impact of Signal Phasing Information Accuracy on Green Light-Optimized Speed Advisory Systems
  Abstract: The highest fuel consumption on urban arterials is associated with driving in congested traffic, characterized by higher speed fluctuations and frequent stops at intersections. One of the ways to reduce excessive stop-and-go driving on urban streets is to optimize signal timings. More recently new methods in traffic signal optimization have incorporated changes in drivers’ behavior to achieve optimum performance at signalized intersections. Connected Vehicles technology provides a two-way wireless communication environment enabling vehicle-to-vehicle and vehicle-to-infrastructure communications, which can be used for a variety of mobility and safety applications. One such application is called GLOSA - Green Light Optimized Speed Advisory. This is a system that uses timely and accurate information about traffic signal timings and traffic signal locations to guide drivers (through infrastructure-to-vehicle communication) with speed advice for a more uniform commute with less stopping time through traffic signals. This paper evaluates a GLOSA implementation for two types of traffic signal timings: predictable fixed-time signal timings and unpredictable actuated-coordinated signal timings. A two-intersection traffic network was modeled in VISSIM to achieve trust-worthy results calibrated in the field. A Comprehensive Modal Emission Model was used to accurately estimate emissions. Experiments included various infrastructure-to-vehicle penetration rates and GLOSA activation frequencies. The results indicate that actuated-coordinated signal timings are not dependable for use in GLOSA systems. For fixed-time signals, higher penetration rates and more frequent GLOSA activations resulted in better traffic performance. GLOSA caused only minor improvements in fuel consumption while average vehicle stopped delay has been improved significantly.
  Authors: Stevanovic, Aleksandar; Stevanovic, Jelka; Kergaye, Cameron
  Authors: Stevanovic, Aleksandar; Stevanovic, Jelka; Kergaye, Cameron
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0641
• Application of Naturalistic Driving Data to Modeling of Driver Car-Following Behavior
  Abstract: The driver-specific data available from naturalistic driving studies provides a unique perspective from which to test and calibrate car-following models. As equipment and data storage costs continue to decline, the collection of data through in situ probe-type vehicles is likely to become more popular, and thus there is a need to assess the feasibility of these data for the modeling of driver car-following behavior. This paper seeks to focus on the costs and benefits of naturalistic data for use in mobility applications. Any project seeking to utilize naturalistic data should plan for a complex and potentially costly data reduction process to extract mobility data. A case study is provided using the database from the 100-Car Study, conducted by the Virginia Tech Transportation Institute. One thousand minutes worth of data comprised of over 2,000 car-following events recorded across eight drivers is compiled herein, from a section of multilane highway located near Washington, D.C. The collected event data is used to calibrate four different car-following models, and a comparative analysis of model performance is conducted. The results of model calibration are given in tabular format, displayed on the fundamental diagram, and shown with sample event charts of speed-vs.-time and headway-vs.-time. The authors demonstrate that the Rakha-Pasumarthy-Adjerid model performs best both in matching individual drivers and in matching aggregate results, when compared with the Gipps, Intelligent Driver, and Gaxis-Herman-Rothery models.
  Authors: Sangster, John; Rakha, Hesham; Du, Jianhe
  Authors: Sangster, John; Rakha, Hesham; Du, Jianhe
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 666
  Paper Number: 13-0594
• Optimization Model for Dispatching Heterogeneous Emergency Vehicles
  Abstract: An emergency is a situation that causes an immediate risk to the property, health, or lives of civilians. Emergency response services such as police, fire, and medical services play crucial roles in all communities and can minimize the adverse effects of emergency incidents by decreasing the response time. The goal of this research is to develop a comprehensive optimization dispatching model for emergency call centers or emergency management centers. This model can come up with the best dispatching algorithm based on real-time information about the status of the emergency-response fleet, traffic information and the status of emergency calls. This problem is formulated as an integer programming model. Three categories of emergency vehicle types are considered in the system: police cars, ambulances, and fire vehicles. The police department is assumed to have a homogeneous fleet, but ambulances and fire vehicles are heterogeneous.
  Authors: Sharifi, Elham; Haghani, Ali; Sadrsadat, Hadi
  Authors: Sharifi, Elham; Haghani, Ali; Sadrsadat, Hadi
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-0686
• Incremental Delay Methodology for Assessing Effects of Nonrecurring Congestion on Freeway Facilities
  Abstract: This paper introduces a method to estimate the incremental effects of different sources of congestion on freeway facility travel time and reliability in a Highway Capacity Manual context. The method relies on generating a suffciently complete set of operational scenarios for a freeway facility to fully describe its operational variability over a one-year reliability reporting period, and under consideration of recurring and non-recurring sources of delay. The method calculates the associated probabilities for each scenario and produces a variety of performance measures at the facility level for each 15-minute analysis period. Using these data and associated scenario probabilities, the method calculates the contribution of each source of congestion to the performance measure of interest, distinguishing between the base recurring delay, and the incremental effects of impacts from weather and incidents. The method was applied to a 12.5 mile freeway facility on I-40 near Raleigh, North Carolina to illustrate the approach. Based on the findings, the demand level was the main contributor to delay on the facility. In fact, 85% of the delay was attributable to demand level. Inclement weather and incidents contributed at most 15% of delay for the study site of which around 12% was attributable to incidents and the remaining 3% to inclement weather. The small impact of inclement weather in our study site was expected as Raleigh is not often exposed to inclement weather events with large capacity reductions. Although inclement weather and incidents increased the delay by at most 15%, they significantly impacted travel time reliability on the study site. Non-recurring congestion yielded a threefold increase in the value of the planning time index, and significant rises in other reliability performance measures. The findings from this research are important, since they highlight that high delays oftentimes attributed to freeway incidents and weather events, may in fact be largely attributable to the underlying recurring congestion. These results are important for agencies exploring the use of active traffic and demand management strategies to improve freeway operations, as they suggest that demand management treatments may result in a larger net-benefit than strategies aimed at capacity management under adverse conditions.
  Authors: Hajbabaie, Ali; Schroeder, Bastian J.; Rouphail, Nagui M.
  Authors: Hajbabaie, Ali; Schroeder, Bastian J.; Rouphail, Nagui M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-0262
• Prevention of Backing Fatalities in Construction Work Zones: Comprehensive Survey of Current Practices and Procedures
  Abstract: The purpose of this paper is to conduct a comprehensive survey of current practices and procedures on the prevention of backing fatalities in construction work zones. A review of fatal backing incidents has been done and indicates that backing fatalities are a real and immediate hazard to most construction work zones. Procedures and policies are reviewed and discussed in detail. First, general work zone safety hazards are reviewed, particularly blind areas are identified. Second, engineering controls currently in use are examined and explained to help understand what steps can be taken to prevent future backing fatalities. The internal traffic control plan (ITCP) is described as one of the most promising engineering solutions to this issue. An ITCP designates the movement of people and equipment through the work zone in an effort to maximize safety by minimizing hazardous situations in the work zone. Third, administrative controls (including signalers, drivers, and workers-on-foot training) are also discussed. These in-house communication educational directives could help workers understand and use safe practices to prevent future backing fatalities. Fourth, existing technology controls are reviewed for use in aiding equipment operators in identifying when pedestrian personnel are in dangerous areas around their equipment (i.e., back-up camera, radar). Finally, a summary of the review is given, and future research directions are discussed.
  Authors: Fan, Wei; Radley, Lee; Carroll, John Clayton; Choe, Soo Young; Leite, Fernanda; Seedah, Dan; Caldas, Carlos
  Authors: Fan, Wei; Radley, Lee; Carroll, John Clayton; Choe, Soo Young; Leite, Fernanda; Seedah, Dan; Caldas, Carlos
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 400
  Paper Number: 13-0323
• Speed Reduction Impacts of Dynamic Speed Feedback Signs on Rural Two-Lane Curves
  Abstract: Horizontal curves are a particular concern since they have approximately three times the crash rate of tangent sections. Curve related crashes have a number of causes including roadway and driver factors with speed as a primary driver factor. Dynamic speed feedback signs are one traffic control device that has been successfully used to reduce vehicle speeds and, subsequently, crashes in urban applications. However, their effectiveness for rural curves has not been demonstrated. This paper describes a national demonstration project to evaluate the effectiveness of 2 different DSFS signs in reducing speed on curves at 22 total sites on rural 2 lane roadways in seven states. Data were collected before and at 1, 12 , and 24 months after installation of the DSFS. On average most sites had decreases in mean speeds with decreases up to 10.9 mph noted for both the PC and center of curve. Most sites experienced changes in 85th percentile speed of 3 or more mph at the PC with the majority of sites having a decrease of 2 mph at the center of curve. The number of vehicles traveling 5, 10, 15, or 20 mph over the posted or advisory speed limit was also compared. Large reductions in the number of vehicles traveling over the posted or advisory speed occurred for all of the after periods at the PC and center of curve indicating that the signs were effective in reducing high end speeds, as well as average and 85th percentile speeds.
  Authors: Hallmark, Shauna; Smadi, Omar G.; Hawkins, Neal R.
  Authors: Hallmark, Shauna; Smadi, Omar G.; Hawkins, Neal R.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-0366
• Models for Estimation of Drivers’ Impatience on Two-Lane Rural Highways
  Abstract: The main objective of the study was to model the decision making process of drivers during passing maneuvers performed on two-lane rural highways, using only traffic characteristics. By limiting the input data in this way, the findings and their implications become applicable to any two-lane road segment. On two-lane highways, when traffic volume increases, drivers may be unwilling to travel in platoons, resulting in an increased willingness to execute risky passing maneuvers. This phenomenon has been called “drivers’ impatience”. The study proposes an empirical method for evaluating drivers’ impatience using the concept of a critical passing gap. It was found that the critical passing gap has a bounded decreasing function determined by the total traffic volume or the volume in the oncoming lane. The critical passing gaps were found to be Log-Normally and Normally-distributed with an average value of 16.5 seconds, and a standard deviation of 5.5 seconds.
  Authors: Rozenshein, Sofya; Polus, Abishai; Cohen, Moshe
  Authors: Rozenshein, Sofya; Polus, Abishai; Cohen, Moshe
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-0451
• Evaluation of VISSIM and FREEVAL to Assess an Oversaturated Freeway Weaving Segment
  Abstract: The HCM 2010 does not provide a methodology to assess Level-of-Service (LOS), density, and space mean speed for oversaturated freeway weaving segments. In its supplemental chapters it suggests use of either analytical tool called FREeway EVALuation (FREEVAL) or a commercial microsimulation software. This study evaluates ability of such tools to realistically generate density and speed on oversaturated freeway weaving segments. The study utilizes NGSIM data for an oversaturated weaving segment on a US 101 Hollywood Freeway in California to populate FREEVAL and VISSIM (a representative of commercial microsimulation software) models. Both models are calibrated, to the best possible extent, to replicate field data for the first two 15-minute intervals from NGSIM data set. The last 15-minute interval is used to assess ability of these tools to reproduce performance measures on an oversaturated freeway segment. Results show that FREEVAL is not able to accurately estimate both speed and density of oversaturated freeway weaving segment. On the other hand, the results showed that VISSIM microsimulation model can be successfully calibrated to replicate speed and density from the field but only after introducing a speed reduction areas to emulate effects of queue propagation from downstream (out of model) links.
  Authors: Jolovic, Dusan; Stevanovic, Aleksandar
  Authors: Jolovic, Dusan; Stevanovic, Aleksandar
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 398
  Paper Number: 13-0484
• Vehicle-Class-Specific Control of Freeway Traffic
  Abstract: Active Traffic Management (ATM) aims at reducing congestion levels and the costs that are induced by it. Currently, most ATM measures disregard the vehicle classes traffic is composed off. Nevertheless, few measures proposed are indeed vehicle-class specific, such as high-occupancy and toll lanes (HOT) or truck lanes. Recently, multi-class versions of ramp meters and route guidance have been developed and analyzed in terms of traffic flow theory. However, they have never been combined or coordinated to reduce the traffic of a realistic freeway.In this paper, we develop a multi-class controller for Active Traffic Management and apply it in simulations of a freeway with heavy truck traffic. By coordinating a multi-class ramp meter and two multi-class route guidance measures in an optimal control approach, the traffic conditions are improved compared to their mixed-class counterparts. These results suggest that the costs of congestion are reduced if Active Traffic Management is applied vehicle-class specifically.
  Authors: Schreiter, Thomas; Van Lint, Hans; Hoogendoorn, Serge
  Authors: Schreiter, Thomas; Van Lint, Hans; Hoogendoorn, Serge
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-0585
• Enhancements to Freeway Facilities Method in the Highway Capacity Manual to Enable Reliability Analysis
  Abstract: The freeway facilities methodology in the Highway Capacity Manual (HCM) covers both under saturated and over saturated traffic regimes. The methodology provides a fast and reliable approach for analyzing freeway traffic operations and research is ongoing to add a reliability analysis component to the method. For that purpose, several key methodological enhancements are needed to make the method “reliability ready”, which are described and illustrated in this paper. These enhancements include: incorporation of capacity drop in queue discharge flow compared to pre-breakdown flow, adding Speed Adjustment Factor (SAF) as a new lever for modeling non-recurrent congestion sources like weather and incidents, modeling improvement of SAF and Capacity Adjustment Factor (CAF) in merge, diverge, and weaving segments, using new defaults of SAF and CAF for freeways, and adding new congestion performance measures. Further enhancements are made to explicitly incorporate CAF and SAF into methodologies for weaving and merge/diverge segments, which were typically assumed to operate as basic freeway segments for CAF less than 1.0. In order to generate a cumulative travel time distribution for reliability analysis, thousands of data points are generated with the automated version of the freeway facilities computational engine. In addition to the existing performance measures generated by the computational engine, some new output variables are proposed in the form of the Travel Time Index (TTI) and a Denied Entry Queue Length (DEQL) measure. The various enhancements are illustrated using computational examples and a discussion is offered as to their effects on conventional freeway facilities analysis, without the evaluation ofreliability.
  Authors: Sajjadi, Soheil Seyyed; Schroeder, Bastian J.; Rouphail, Nagui M.
  Authors: Sajjadi, Soheil Seyyed; Schroeder, Bastian J.; Rouphail, Nagui M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-0600
• Operational Effects of CFI Geometrics: A Deterministic Model for Continuous Flow Intersections
  Abstract: The Continuous Flow Intersection (CFI), also known as a Displaced Left Turn (DLT) intersection, increases capacity and reduces delays by eliminating the left turn traffic signal phase. This is achieved by changing the geometric layout of the intersection so that left turns cross opposing traffic lanes at a location upstream of the main intersection. Although the installation of CFIs has become more prevalent in the United States (US), insights to CFI geometrics gained through their application have not yet been dispersed to industry or academia. This paper considers the impacts that geometric design has on the operations of CFIs. It presents a deterministic model that considers the effects of the DLT length and other CFI geometrics on traffic operations. Although “academic” in nature, this model evolved through practical application. The model takes functional and operational insights gained through the analysis, design, and observation of multiple operational CFIs in Utah and articulates them in mathematical terms. The quantitative relationships presented provide transportation professionals and officials more accurate and precise guidance to facilitate better decisions when considering, evaluating, and designing a CFI.
  Authors: Carroll, Diego H.; Lahusen, Derek
  Authors: Carroll, Diego H.; Lahusen, Derek
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 405
  Paper Number: 13-0428
• Gate Violations by Truck Drivers at Highway-Rail Grade Crossings
  Abstract: The objective of this research was to empirically investigate truck drivers’ gate violations at dual-quadrant gated highway-rail grade crossings (HRGCs). The issue of collisions between trucks and trains is important because of the relatively high severity of such crashes and safety and environmental concerns arising from possible spillage of hazardous materials.The adopted methodology consisted of collecting data on gate violations by truck drivers during train crossing events at two HRGCs and statistically analyzing the dataset. About 22% of the collected observations involved gate violations by truck drivers. Analysis results showed that the frequencies of gate violations increased with higher truck traffic arriving during crossing events. Drivers of single-unit trucks displayed a greater propensity for gate violations compared to drivers of trucks with trailers. Violations were more frequent with longer times between the onset of flashing lights and train arrivals at the crossings. Results also showed that nighttime was associated with higher frequency of gate violations by truck drivers. Implications of the findings, practical options for reducing truck drivers’ gate violations at HRGCs, and recommendations for future research are provided.
  Authors: Khattak, Aemal
  Authors: Khattak, Aemal
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 338
  Paper Number: 13-0742
• Collisions in Freeway Traffic: Influence of Downstream Queues and Interim Means to Address Them
  Abstract: Findings from previous studies indicate that a freeway traffic collision is more likely to occur in close physical proximity to the tail of a queue. The implication is that collision likelihood increases when drivers abruptly alter their trajectories (e.g. by decelerating or changing lanes) upon encountering the queue. The implication is supported, and actually bolstered, with new and more detailed data that were painstakingly extracted from two freeway stretches in California. These data show how the likelihood of collision grows larger as both the spatial and the temporal proximities to the tail of a queue become smaller. It follows that collision risk may be reduced by instructing drivers to begin gently decelerating while still upstream of queues. Retarding vehicle progress toward a queue’s tail could retard the rate by which the likelihood of collision grows with time. And having vehicles approach a queue at diminished speeds may diminish the expected severity of a collision, should one still occur.An outline for simple control logic is offered with the above in mind. The idea is to issue suitable speed advisories to drivers as they approach a queue. The logic could be made a resident tool in freeway traffic management centers. It could thereafter assist freeway managers to select specific speed advisories so as to diminish the empirical estimate of collision likelihood at a specified time in the immediate future, and by some target amount. In the interim, the likelihood estimates would be based solely on vehicles’ spatiotemporal proximities to queues. Other causal influences are ignored for now, though planned experiments to test and improve the present logic are discussed.
  Authors: Li, Zhibin; Chung, Koohong; Cassidy, Michael J.
  Authors: Li, Zhibin; Chung, Koohong; Cassidy, Michael J.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 337
  Paper Number: 13-0746
• Intersection Management for Autonomous Vehicles Using Cooperative Adaptive Cruise Control Systems
  Abstract: One of the expected features for the automated vehicles in the near future is Cooperative Adaptive Cruise Control (CACC) systems. CACC systems are one of the main applications for the connected vehicles initiative of the USDOT for providing better connectivity, safety and efficient mobility in transportation. It is expected in the future that many (or most) of the vehicles will be fully automated; thus the movements of these vehicles can be optimized. Accordingly, this paper presents a new tool for optimizing the movements of autonomous vehicles through intersections: iCACC. The iCACC controller controls vehicle trajectories entering an intersection to avoid collisions while minimizing the intersection delay. In order to validate the proposed algorithm, four intersection control scenarios were analyzed, namely: a traffic signal, an all-way stop control (AWSC), a roundabout, and the iCACC controller, considering different traffic demand levels ranging from a volume-to-capacity ratio of 0.27 to 0.91. Two measures of effectiveness were considered: average vehicle delay and fuel consumption. The simulated results showed savings in delay and fuel consumption of the order of 90 and 45 percent, respectively compared to AWSC and traffic signal control. Delays for the roundabout and the iCACC controller were comparable. The simulation results showed that fuel consumption for the iCACC controller was, on average, 33%, 45% and 11% lower than the fuel consumption for the traffic signal control, AWSC and roundabout scenarios, respectively.
  Authors: Zohdy, Ismail; Kamalanathsharma, Raj Kishore; Rakha, Hesham
  Authors: Zohdy, Ismail; Kamalanathsharma, Raj Kishore; Rakha, Hesham
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 674
  Paper Number: 13-0772
• Complete Enough for Complete Streets? Testing the Sensitivity of HCM 2010 Multimodal Level of Service Under Conditions of Change
  Abstract: An increasing number of jurisdictions across the United States are exploring level of service (LOS) for multiple travel modes, in part due to the release of the 2010 Highway Capacity Manual (HCM 2010) as well as an increased focus on complete streets. One of the most important questions these jurisdictions are asking is whether new multimodal LOS (MMLOS) methods are sensitive enough to inform transportation investments, impact mitigation, or the prioritization of future projects. For this paper, transportation professionals (pubic, private, and academic) were surveyed about inputs they believed would have the greatest effect on pedestrian, bicycle, transit, and auto LOS or inputs they thought would have the greatest likelihood of being changed (i.e., to mitigate an impact or to improve existing conditions). Sensitivity testing was then performed at locations in four cities to measure how 2010 HCM MMLOS scores responded as these inputs were incrementally increased or decreased. While many inputs performed as expected, the testing also found cases where outputs were of a questionable direction or magnitude. The results of this study are informative for agencies considering adopting HCM 2010 MMLOS for purposes of mitigation, resource allocation, or strategic decision making. They also provide a starting point for additional research needed to enhance MMLOS methods.
  Authors: Carter, Peter; Núñez, Miguel; Peters, Sarah; Campbell, Julia; Martin, Francisco; Raykin, Leon; Milam, Ron
  Authors: Carter, Peter; Núñez, Miguel; Peters, Sarah; Campbell, Julia; Martin, Francisco; Raykin, Leon; Milam, Ron
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-0786
• Mitigating Negative Impacts of Near-Side Bus Stops on Cars
  Abstract: Bus stops are often placed short distances upstream of signalized intersections. Buses that dwell at one of these so-called near-side stops can impede queued cars upstream from discharging through the intersection during green times. Residual car queues can form at the intersection as a result. The smaller the distance between a stop and its intersection, the greater the problem can be.Models are formulated to address this problem using kinematic wave theory. The models can be used to determine where to place a near-side stop to achieve a target level of residual car queueing. In addition, the models are used herein to develop a scheme for mitigating residual car queues by briefly detaining some buses from reaching the stop. The scheme can be applied selectively, so that the times that detained buses depart from the stop are not postponed. The buses are therefore not delayed over the longer run. Analysis indicates that this bus-holding scheme can significantly reduce car delays and queueing. Our models for placing stops and holding buses are shown to be robust to systematic and random changes in car flow.
  Authors: Gu, Weihua; Cassidy, Michael J.; Gayah, Vikash V.; Ouyang, Yanfeng
  Authors: Gu, Weihua; Cassidy, Michael J.; Gayah, Vikash V.; Ouyang, Yanfeng
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 807
  Paper Number: 13-0788
• Evaluation of Different Bus Priority Functions in Coordinated Traffic Signals
  Abstract: Delay at signalized intersections is a considerable part of the journey time for public transport (PT) in urban areas, but the delay can be reduced with PT priority in the signals at a relatively low cost to other traffic. The impact on other traffic is dependent on what priority functions are used, but the effects are hard to calculate in a coordinated system and do not always act intuitively. In this paper are experiments with a microscopic traffic simulation model and a software-in-the-loop signal controller simulator conducted to study the costs and benefits, primary in terms of travel times, for busses and other traffic of different priority functions in the Swedish PRIBUSS method for conditional active bus priority. Based on the analysis of the different functions are new conditions for priority proposed and tested with simulations.
  Authors: Wahlstedt, Johan
  Authors: Wahlstedt, Johan
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0818
• Probabilistic Design of Freeway Entrance Speed Change Lanes Considering Acceleration and Gap Acceptance Behavior
  Abstract: An adequate length of entrance speed change lanes (SCL) is required for vehicles’ acceleration and gap searching purposes so that they can merge onto the freeway comfortably. The current design guides use a deterministic approach for the design of SCL length based only on the acceleration behavior of SCL vehicles. This study introduces a probabilistic approach for the design of SCL length considering both acceleration and gap acceptance behavior of drivers during the merging process. A microscopic simulation is used, coupled with Monte Carlo simulation technique, to develop a probabilistic model to evaluate the probability of forced merge by SCL vehicles, termed as the probability of non-compliance (PNC). Different reliability measures can be developed based on the distribution of PNC values for all simulated SCL vehicles at a specific site. Several such measures were estimated for seven study sites and were shown to have high potential to indicate the safety performance at entrance SCL sites. As an example application of the developed model, the mean PNC was estimated to the recommended SCL lengths in North American design guides for a specific freeway design speed but different values of controlling curve design speed and traffic volume on the freeway right lane. The results indicate that the mean PNC may change with the change of either the design speed of the ramp controlling curve or the traffic volume on the freeway right lane.
  Authors: Fatema, Tazeen; Hassan, Yasser
  Authors: Fatema, Tazeen; Hassan, Yasser
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 253
  Paper Number: 13-0819
• Methodology for Developing HCM-Based Oversaturated Speed Flow Model
  Abstract: Oversaturated speed, flow and density relationships are of key importance for freeway operations studies. The Highway Capacity Manual (HCM) oversaturated model defined by a linear transition from flow and density at capacity to zero flow at jam density in the flow-density space provides a reasonable general representation of this relationship but does not provide an unbiased representation for all freeway facilities with different road conditions or driver behavior. This study proposes a method for fitting the HCM model to oversaturated flow and density. Fifteen-minute aggregated flow rate and speed data from Traffic.com fixed-location sensors at three sites on North Carolina (NC) urban freeways in 2010 were collected. Density was calculated as flow rate divided by speed. The fitted models for these sites were compared to the default HCM model. A set of thresholds was defined to identify eligible sensor observations that represent steady state, congested traffic conditions. Results reveal that data observations under inclement weather, lane closures, or incidents will bias the model fitting results and thus need to be filtered out. The steady state congestion data identified in the manner proposed in this study fit well with the HCM-based linear flow-density oversaturated model. This method avoids possible bias caused by capacity and jam density differences between the default HCM model and specific site models, and thus the fitted models represent the actual traffic characteristics relationships better than the default HCM models do. Therefore fitting a site-specific HCM-based model is recommended for sites with sufficient speed and flow data.
  Authors: Xu, Yilun; Williams, Billy M.; Rouphail, Nagui M.; Chase, R. Thomas
  Authors: Xu, Yilun; Williams, Billy M.; Rouphail, Nagui M.; Chase, R. Thomas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-0823
• 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
• A Mode-Neutral Innovation Framework for Commuter Transport: Part 1
  Abstract: Innovation in all fields is recognized as a high risk activity, with many more failures than successes. In commercial product and service innovation, “Customer-Outcome Driven” innovation has been recognized by leading companies as a more effective foundation for innovation. Central to the outcome-driven approach is the methodical identification of desired customer outcomes and the use of survey data to identify underserved outcomes that represent opportunities for development of innovative solutions. This paper explores the application of this technique to commuter travel, to the job of ‘making a daily trip to and from a destination’, with the overall goal of understanding what it would take to increase “passengership” and concludes that the approach delivers potentially useful results. Further research is recommended, and the authors call for metropolitan areas to help with further data collection, solution development and deployment.
  Authors: Minett, Paul; Pearce, John H.
  Authors: Minett, Paul; Pearce, John H.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Pedestrians and Bicyclists; Planning and Forecasting
  Session: 559
  Paper Number: 13-0838
• Evaluation of Recommended Variable Speed Limits for Motorway Traffic Control: Case of E4 in Stockholm, Sweden
  Abstract: Variable Speed Limits (VSL) is a form of motorway control introduced to improve the operations of freeway facilities under congested conditions. This paper evaluates the impact of VSL on the E4 motorway in Stockholm using microsimulation. The test site is heavily congested and in-cludes an integrated Motorway Control System with advisory VSL and Automatic Incident Detection (AID) logic. Experience indicates that the impacts of VSL on traffic condition and safety might be higher if the displayed VSL were mandatory. The objective of the study is to assess the impact of the level of driver compliance to VSL recommended speed, using microsimulation.
  Authors: Nissan, Albania
  Authors: Nissan, Albania
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-0858
• Control Strategy for Rural Variable Speed Limit Corridor
  Abstract: Speed and speed variance among the vehicles are important factors related to safety, especially during the severe weather conditions. A variable speed limit (VSL) system was implemented in 2009 by the Wyoming Department of Transportation (WYDOT) to change the posted, enforceable speed limits in an effort to improve safety. During the initial years of implementation, decisions regarding the posted speed limit were made by maintenance, highway patrol and traffic management center personnel. This paper discusses the development of a methodology to support speed posting decisions based on the real time observed vehicle speeds and weather variables. The results from this methodology indicate that there could be a significant increase in speed compliance and reduced speed variation with the implementation of an automated control strategy over the current manual protocol.
  Authors: Sabawat, Vijay; Young, Rhonda Kae
  Authors: Sabawat, Vijay; Young, Rhonda Kae
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 375
  Paper Number: 13-0874
• Calibrating Road Design Guides Using Risk-Based Reliability Analysis
  Abstract: Existing geometric design guides provide deterministic design standards for highway elements which ignores the uncertainty associated with many design parameters. Reliability analysis has been advocated as an approach to account for this uncertainty and to evaluate the risk associated with a particular design feature. This paper discusses one important application of reliability analysis: the calibration of geometric design models to yield consistent safety (risk) levels. The paper provides calibrated design charts for the middle ordinate (M), defined as the lateral distance between edge of median barriers and centerline of the adjacent traffic lane, at different probability of non-compliance levels. The results show that the calibrated values of middle ordinate (M) are generally lower than those derived from the AASHTO design guide. The calibrated design charts can offer designers dealing with highways with constricted right-of-way an option to use lower middle ordinate values and enable them to estimate the safety consequences of their decisions. Overall, the calibrated charts can aid the decision maker in determining the safety implications of deviating from geometric design standards and quantifying the safety level built in design values that are deemed acceptable.
  Authors: Hussein, Mohamed Hussein Azab; Sayed, Tarek; Ismail, Karim; Van Espen, Adinda
  Authors: Hussein, Mohamed Hussein Azab; Sayed, Tarek; Ismail, Karim; Van Espen, Adinda
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 405
  Paper Number: 13-0877
• Cost-Stable Truck Scheduling at Cross-Dock Facility with Unknown Truck Arrivals
  Abstract: In this paper, we analyze a cross-dock operator’s problem of determining a cost-stable scheduling strategy while minimizing the average of total service costs in case of unknown truck arrival times. A bi-objective optimization problem is formulated and we discuss a genetic algorithm based heuristic to ?nd Pareto e?cient schedules. The proposed approach is compared to ?rst-come-?rst-served policies.
  Authors: Konur, Dincer; Golias, Mihalis M.
  Authors: Konur, Dincer; Golias, Mihalis M.
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-0882
• Using a Multi-agent Simulation Tool to Estimate the Carpooling Potential
  Abstract: It is a general trend in transportation planning to try to minimize the negative externalities of the transport system as a whole, such as noise or pollutant emissions. One of the ways to achieve this is to reduce the number of cars on the roads, for instance by increasing car occupancy. This paper focuses on evaluating the potential of this possibility. The factors influencing this potential are manifold: behavioral, structural (number of potential matches), organisational (quality of available services to meet co-travelers)... In previous studies, mainly the behavioral and organisational factors were analyzed. This paper focuses on the structural factor. To do so, the highly detailed daily plans generated by the multi-agent microsimulation software MATSim are searched for potential matches. Information about the potential matches is used to assess the feasibility of carpooling. In particular, it is shown that when considering only structural factors, it is possible to group most of the car trips into two-person car-pools. The results of the analysis lead to the conclusion that there is no structural obstacle to carpooling development, and thus that the causes of the low share of this mode is to search in both the behavioral and organisational factors.
  Authors: Dubernet, Thibaut; Rieser-Schüssler, Nadine; Axhausen, Kay W.
  Authors: Dubernet, Thibaut; Rieser-Schüssler, Nadine; Axhausen, Kay W.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Pedestrians and Bicyclists; Planning and Forecasting
  Session: 559
  Paper Number: 13-0866
• Pedestrian and Bicycle Level of Service at Intersections, Roundabouts, and Other Crossings
  Abstract: The Danish Road Directorate sponsored a study to develop methods for objectively quantifying pedestrian and cyclist stated satisfaction with roundabouts, signalized and non-signalized intersections, mid-block crossings, and pedestrian bridges and tunnels (in short: crossings). The results provide a measure of how well urban and rural crossings accommodate pedestrian and bicycle travel. In order to determine how existing traffic operations, geometric conditions, and other variables affect pedestrian and cyclist stated satisfaction, 180 randomly selected Danes were shown a total of 158 video clips from 95 crossings filmed by a walking pedestrian and a riding cyclist. Respondents rated crossings on a six-point scale ranging from very dissatisfied to very satisfied. This resulted in 3,023 pedestrian and 3,998 cyclist ratings. Crossings and video clips were described by about 300 variables.Pedestrian and cyclist satisfaction models were developed using cumulative logit regression of ratings and variables. The models include variables, which relate significantly (p <= 0.05) to the satisfaction ratings. Variables such as type, width and height of pedestrian and bicycle facility, length of crossing, size of roundabout, width of roadway, traffic volume, waiting time and speed limit significantly influence the level of satisfaction.Models return percentage splits of the six levels of satisfaction. These splits are then transformed into a level of service (LOS). The models provide traffic planners and others the capability to rate crossings with respect to pedestrian and cyclist satisfaction, and may be used in the processes of evaluating existing, designing new or redesigning existing crossings.
  Authors: Jensen, Søren Underlien
  Authors: Jensen, Søren Underlien
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-0950
• Defining Spatiotemporal Influence Areas in Freeways for Secondary Accident Detection
  Abstract: Current research on secondary crash identification links the likelihood of secondary crashes occurrence to primary incidents using pre-defined spatial and temporal criteria. This paper extends past research on secondary crash detection by defining dynamic thresholds of the influence area of a primary incident using detailed real-time collected freeway traffic data from upstream loop detectors. Results offer influence curves for different characteristics with respect to the prevailing traffic conditions before the occurrence of the primary incident, to crash characteristics such as the number of vehicles involved or the number and type of blocked lanes. For accurately detecting secondary incidents, an empirical speed-based method is applied that imprints influence areas with respect to their dissipation pattern. The results of the proposed approach are compared to those of five prevailing static and dynamic methods for detecting secondary accidents and the differences are identified and discussed.
  Authors: Imprialou, Maria-Ioanna Marianna; Orfanou, Foteini P.; Vlahogianni, Eleni I.; Karlaftis, Matthew G.
  Authors: Imprialou, Maria-Ioanna Marianna; Orfanou, Foteini P.; Vlahogianni, Eleni I.; Karlaftis, Matthew G.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 337
  Paper Number: 13-0955
• Feedback Gating Based on Sparse-Measurement Urban Network Fundamental Diagrams
  Abstract: Based on the recently proposed concept of an operational urban NFD (Network Fundamental Diagram) and a feedback gating procedure, it is shown that simple, practicable and efficient gating control may be based on a strongly reduced amount of real-time measurements. The urban network of Chania, Greece, is used as a test-bed for the investigations within a realistic microscopic simulation environment. The results indicate that reduced NFDs, obtained with far less measurements than for a complete NFD, exhibit a critical range of traffic states that is virtually equivalent to its counterpart of the complete NFD; and that the provision of accordingly reduced amounts of real-time measurements for feeding the feedback regulator leads to virtually equivalent gating results as in the full measurement case.
  Authors: Keyvan-Ekbatani, Mehdi; Papageorgiou, Markos; Papamichail, Ioannis
  Authors: Keyvan-Ekbatani, Mehdi; Papageorgiou, Markos; Papamichail, Ioannis
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 213
  Paper Number: 13-0958
• Short-Term Online Queue Predictor Based on Cell Transmission Model and Unscented Kalman Filter
  Abstract: The urban traffic queue predictor presented in this paper was projected to be used online with traffic control systems that require cycle-by-cycle updated queue estimates. The technique is divided in three steps: it estimates past queues on the urban road segments that are equipped with ordinary induction loop detectors; then uses these estimated queues as the input data to an Unscented Kalman Filter (UKF). The UKF uses the Cell Transmission Model (CTM) as it's nonlinear function, and, taking into consideration the dynamics of the network, is capable of improving the queue estimates; the last step uses the improved estimates as an starting point for the prognosis step that is run with the CTM. The improvement brought by the technique was confirmed through the simulation of different scenarios in an emulated real-life network.
  Authors: Dantas, Luciano Dionisio
  Authors: Dantas, Luciano Dionisio
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0965
• Univariate Volatility-Based Models for Improving Quality of Travel Time Reliability Forecasting
  Abstract: The literature is rich in travel time prediction considering its importance in intelligent transportation system. Despite proliferation of advanced methodologies, modeling the uncertainty of traffic conditions is still a challenge, especially during congested situations. Travel time reliability associated with its time-dependent variation gives a way to measure the system performance and has been received extensive attention in recent years. In practice, one of the measures for travel time reliability is the identification of prediction interval, which has many potential applications in the development of systems that aimed at disseminating real time traffic information to travelers, such as the advanced traveler information systems (ATIS). From the management point of view, the prediction interval forecasts the unreliable traffic periods, enables the selection of proper strategy to avoid or release possible traffic congestion. GARCH model has been proved the ability of modeling the uncertainties in several literatures. However, it has some drawbacks in traffic forecasting. To improve the quality of travel time reliability forecasting, this paper proposes two univariate volatility models and compared their performance in generating high-quantity PIs. Travel time data collected from AVI stations located along U.S. Highway 290 in Houston, Texas is used to exam each model’s performance in travel time reliability forecasting. Study results indicate that all three models give reasonable prediction intervals that could be used to indicate the variability of future traffic conditions. The statistical analysis and forecasting results indicates that the proposed GIR-GARCH model outperformances the other two models in constructing better PIs.
  Authors: Zhang, Yanru; Sun, Ranye; Haghani, Ali; Zeng, Xiaosi
  Authors: Zhang, Yanru; Sun, Ranye; Haghani, Ali; Zeng, Xiaosi
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 546
  Paper Number: 13-0966
• Effectiveness of Graphic-Aided Portable Changeable Message Signs in Reducing Vehicle Speeds in Highway Work Zones
  Abstract: Portable changeable message signs (PCMSs) have been employed in highway work zones as a temporary traffic control device for decades in the United States. Results of previous research showed that the traditional text-based PCMS had several limitations, such as having a short range of legibility and being difficult to read by elderly and non-English-speaking drivers. A few simulation studies indicated that using graphic-aided PCMSs could likely overcome these limitations. This paper presents the results of field experiments that were conducted to determine the effectiveness of graphic-aided PCMS in reducing vehicle speeds in the upstream of highway work zones. In field experiment Phase I, a full-matrix PCMS was programmed to display a work zone graphic and a flagger graphic, which were similar to the W21-1 sign and W20-7 sign, respectively, specified by the Manual on Uniform Traffic Control Devices. In field experiment Phase II, the PCMS was programmed to display two alternative work zone graphics along with the original work zone graphic. 1,115 and 1,600 valid vehicle speed data were collected during field experiments Phase I and Phase II, respectively. The results of data analysis suggested that graphic-aided PCMSs reduced mean vehicle speeds between 13% and 17% in the upstream of a work zone. This study provided valuable knowledge to government agencies and the transportation industry on how to regulate and implement graphic-aided PCMS in highway work zones.
  Authors: Huang, Yilei; Bai, Yong
  Authors: Huang, Yilei; Bai, Yong
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 400
  Paper Number: 13-0971
• Intelligent Transportation System Application: Design and Evaluation of Intelligent Dilemma-Zone Protection System for High-Speed Rural Intersection
  Abstract: This paper presents the design and evaluation of a dilemma zone protection system that utilizes the dynamic detection technology to track individual vehicles as they approach an intersection of interest. A high-speed rural intersection in Maryland experiencing a high frequency of crashes was selected for system installation and evaluation. Data collected from 3 microwave sensors deployed along the target approach were used in real time to control the signal logic, providing green or all-red extensions when the pre-defined parameters of detected vehicles are met. To evaluate the performance of the system design and the effectiveness of the associated parameters, a field test was further conducted. The data analysis included the identification of false called red extensions (related to efficiency) and missed red extensions (related to safety) to assess the overall performance of the newly installed system. Results indicate that the newly designed dynamic dilemma zone protection system using an all-red extension offers distinct advantages over traditional systems by providing additional protection to high-speed vehicles even when they are in the “cannot pass zone” and make incorrect passing decisions.
  Authors: Chang, Gang-Len; Franz, Mark L; Liu, Yue; Lu, Yang (Carl); Tao, Ruihua
  Authors: Chang, Gang-Len; Franz, Mark L; Liu, Yue; Lu, Yang (Carl); Tao, Ruihua
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0973
• Enhancing Work Zone Travel Time Estimation Using Smart Work Zone Data
  Abstract: An increasing number of transportation agencies around the states have considered and/or implemented the smart work zone (SWZ) concept where sensors are deployed upstream of a lane closure to detect queue conditions and provide advanced warning to approaching travelers via portable changeable message sign (PCMS). The travel time monitoring technology such as Bluetooth-based identification matching may also be deployed in conjunction with queue detection system at the SWZ. This paper extends the utility of data collected from SWZ where both queue and travel time monitoring technologies are present to improve the accuracy of travel time estimation and estimate travel delay. The proposed algorithm utilizes historical and real-time traffic conditions collected from SWZ to estimate queue length and travel time when SWZ is active. The algorithm was evaluated and calibrated using a VISSIM simulation test bed for the southbound direction of a 29-mile segment along I-35 corridor from Hillsboro to Waco, Texas. Researchers simulated speed sensors and Bluetooth technology characteristics using VISSIM Vehicle-to-Device (Car2X) technology for the purpose of the algorithm evaluation. The evaluation results indicated that the proposed algorithm, once calibrated with historical data, can provide significant improvement in real-time travel time and delay estimation especially where the volume-to-capacity (v/c) ratio regularly exceeds 1.0 (unsteady queue condition).
  Authors: Songchitruksa, Praprut; Middleton, Dan
  Authors: Songchitruksa, Praprut; Middleton, Dan
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 339
  Paper Number: 13-0989
• Longitudinal Performance Measures for Assessing Agencywide Signal Management Objectives
  Abstract: A fundamental concept of system engineering is defining operating objectives. Once those are defined, it is important to select the appropriate strategy and performance measure for assessing how well the strategy is working. This paper identifies two operating objectives that we feel are broadly shared by many agencies: i) Good communication to traffic signal infrastructure and ii) Good allocation of green times. One of these objectives is clearly oriented at asset management, and the other at operations. However, there are substantial synergies between both objectives. This paper proposes performance measures for evaluating whether those objectives are being met. The quality of communication is evaluated by examining connectivity and data completeness based on an open standard telecommunications model. Opportunities to improve green time allocation are detected by identifying patterns in phase events. The performance measures are presented in an easy-to-understand visual format that we believe is useful for practitioners. One of the outcomes of this system engineering approach is the realization that many of our objectives can be achieved with a high-latency, low-bandwidth communication infrastructure, provided the appropriate processing techniques and performance measures are clearly articulated. The paper illustrates explains this architecture and performance measures in the context of a deployment of 125 intersections geographically distributed throughout the state of Indiana using a variety of communication infrastructure ranging from commercial cellular data to agency-owned fiber.
  Authors: Li, Howell; Hainen, Alexander Michael; Day, Christopher M.; Grimmer, Gannon; Sturdevant, James R.; Bullock, Darcy M.
  Authors: Li, Howell; Hainen, Alexander Michael; Day, Christopher M.; Grimmer, Gannon; Sturdevant, James R.; Bullock, Darcy M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0980
• Corridor-Level Approach for Estimating the Contribution of Incidents to Delay
  Abstract: Understanding the relationship between incidents and delay is an important step in developing targeted measures to reduce non-recurrent congestion. Research over the last decade has focused on two key incident characteristics that dictate how much delay an incident will cause: (1) the incident clearance time; and (2) the capacity reduction of the incident. Research relating congestion with incidents has primarily leveraged incident data sets that report on these key variables; however, the reality is that data sets that report this information are uncommon and often take a year or more to produce. Until standards have been developed for incident reporting, work is needed to demonstrate how to best use more commonly available data sets to relate incidents with congestion. The goal of this paper is to present methods for maximizing the use of operational incident data sets for non-recurrent congestion analysis. It uses Computer-Aided-Dispatch data from the California Highway Patrol, which is continuously available in real-time, to estimate the amount of delay caused by different types of incidents. It builds upon previous research by accounting for the fact that different types of incidents have varying congestion impacts depending on the corridor and the time of day. This paper applies the developed methodology to a segment of northbound Interstate-880 in the San Francisco Bay Area, where an Integrated Corridor Management project is in progress. The outputs of the methodology can be used to identify priority time periods and corridors for incident management strategies.
  Authors: Barkley, Tiffany Elizabeth; Spiro, Arlen; Burnworth, Sarah; Victor, Radiah
  Authors: Barkley, Tiffany Elizabeth; Spiro, Arlen; Burnworth, Sarah; Victor, Radiah
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 337
  Paper Number: 13-0999
• Novel Cell Transmission Model-Based Simulations of Left-Turn Blockages Inside Intersections
  Abstract: Simulation of oversaturated conditions has remains a challenge. Specifically, among many factors, left turn blockage might further complicate the simulation. In oversaturated conditions, left turns are not only blocked by the oversaturated through traffic from the same direction in a segment at intersections, but also can be blocked by the spillback of through traffic from the opposite direction within an area of intersections. The objective of this research is to propose, develop and test a new model, proposed as the Conditional Cell Transmission Model (CCTM), which allows for the possibility of an additional cell forming within an intersection to account for any vehicles that may ¡°caught¡± there for some amount of time thereby incurring delay and potentially causing delay to conflicting movements. The results of experiments demonstrate that (1) CCTM can accommodate various traffic demands properly and CCTM¡¯s accurate representation of left turn blockages at intersections; (2) CCTM uses a condition cell to simulate left turn blockages within an area inside an intersection. This feature lets CCTM to reach a new approach in the development of the CTM; (3) In CCTM, users may input the probability of a conditional cell and the probability of the occurrence of a useful gap to match the behaviors of local drivers. This feature is a unique contribution of CCTM. Finally, the consistency between HCS 2010 and CCTM shows that CCTM is a reliable methodology of modeling traffic flow in oversaturated condition.
  Authors: Wang, Ping; Gurupackiam, Saravanan; Jones, Steven Lee; wang, Li
  Authors: Wang, Ping; Gurupackiam, Saravanan; Jones, Steven Lee; wang, Li
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1003
• Hybrid Model for Arterial Traffic Density Estimation
  Abstract: Traffic density is an important congestion indicator and hence real time estimation and prediction of traffic density is essential for congestion management using Intelligent Transportation Systems (ITS). The availability of adequate macroscopic models of sufficient accuracy is a prerequisite for achieving this task. Most of the available macroscopic models use the conservation equation, the fundamental traffic flow relation connecting speed, flow and density and a steady state speed density relation, known as a stream model. For freeways where the traffic is mostly uniform, it can be assumed that a single stream model is applicable for the section between two data collection points. However, traffic conditions along urban arterials are often non-uniform due to the influence of signalized intersections. The situation will be more complex under traffic conditions such as the one existing in India with its heterogeneity and lack of lane discipline. The assumption of a uniform stream model for the entire section between data collection points may not hold good under such scenarios. This paper proposes a hybrid model based scheme for the estimation of traffic density and the model was formulated based on the lumped parameter approach. The choice of different speed-density relationships has been made based on the difference in speed experienced at the entry and exit points of the study section. Using this, a density estimation scheme was obtained based on the extended Kalman filter. The scheme has been implemented and corroborated using data measured from an urban road stretch in Chennai, India, and the results are promising.
  Authors: Thankappan, Ajitha; Vanajakshi, Lelitha Devi; Subramanian, Shankar Coimbatore
  Authors: Thankappan, Ajitha; Vanajakshi, Lelitha Devi; Subramanian, Shankar Coimbatore
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1010
• Providing Speed Advice to Vehicles Approaching an Intersection: Evaluation and Lessons Learned
  Abstract: In this paper an Optimized Dynamic Speed Advise (ODYSA) system is evaluated. This system was developed by DTV Consultants and recently (2010) implemented in the Netherlands in the province Zuid-Holland. ODYSA is designed to minimize, or at least reduce, the number of times the main stream traffic flow is forced to stop due to the presence of traffic lights at intersections. It does so combining traditional signal coordination and the provision of speed advises to vehicles. This system is relatively new in the Netherlands and there are plans to extend its use. The results from the evaluation in terms of fluidity of traffic are positive and promising but, as will be discussed in this paper, some difficult and major issues regarding fine-tuning of the speed advises and the Human Factors interaction with the system should be addressed first.
  Authors: van Katwijk, Ronald; Bakri, Taoufik; Vukovic, Damir; Hogema, Jeroen H.; Steendijk, John
  Authors: van Katwijk, Ronald; Bakri, Taoufik; Vukovic, Damir; Hogema, Jeroen H.; Steendijk, John
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-1019
• Some Traffic Features During On-ramp Queue Flush
  Abstract: Ramp metering of a simple isolated ramp is still a complex problem because of the limited storage on the on-ramp. To prevent on-ramps queues from spilling back to the upstream intersection, transportation agencies generally resort to queue flush policy.While this policy is detrimental to the freeway, there is limited empirical research to understand the causal relationships of various parameters of a queue flush mechanism and their impacts. Towards this end, this research investigated factors that may affectdischarge flow drop. Suitably shifted cumulative curves were utilized to evaluate 28 queue flush instances. It was found that flow ratio could be used to explain the discharge flow drop. This research will help better manage queue flush policy and developalternate strategies that are less detrimental then the current queue flush practice.
  Authors: Chilukuri, Bhargava Rama; Laval, Jorge Andres; Chen, Danjue
  Authors: Chilukuri, Bhargava Rama; Laval, Jorge Andres; Chen, Danjue
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0987
• 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
• Self-Learning Adaptive Ramp Metering: Analysis of Design Parameters on a Test Case in Toronto, Canada
  Abstract: Ramp metering (RM) is the most effective dynamic traffic measure in response to growing congestion in urban freeway networks. Among the extensive RM methods, those based on optimal control theory have shown strong potential in improving freeway performance. However, these algorithms require an accurate traffic model, which limits their applicability in practice. Reinforcement learning (RL) provides the tools to achieve optimal RM control without reliance on any traffic model. In this paper a guideline for designing RM control systems based on RL is presented by testing different states representations, learning methods, action selection, and reward definitions. A microscopic simulation testbed based on a portion of Highway 401 in the city of Toronto is developed to evaluate each of the above design parameters and quantify various ramp metering control strategies. Comparing the reinforcement learning ramp metering (RLRM) algorithm with highly renowned ALINEA, shows the potential of RLRM to improve freeway traffic condition. The proposed RLRM algorithm and ALINEA reduce the total travel time by 40% and 20% with respect to the case with no RM, respectively.
  Authors: Rezaee, Kasra; Abdulhai, Baher; Abdelgawad, Hossam
  Authors: Rezaee, Kasra; Abdulhai, Baher; Abdelgawad, Hossam
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-1054
• Relating Shockwave Propagation Speed and Time Headway Using Microscopic Analysis
  Abstract: Shockwave propagation speed and time headway are key incident precursors, and their timely estimation is critical in designing anticipatory elements of Intelligent Transportation Systems for freeways. We analyze nine shockwaves and the microscopic characteristics of the vehicles involved. Starting with video recordings from incidents on I-94, Minneapolis, vehicle trajectories are extracted. From the trajectories we define flow variables such as speed, deceleration, shockwave propagation speed, time headway and reaction time. Especially for shockwave propagation speed and time headway we provide distribution fitting results for the delivered datasets. Finally, a nonlinear relationship between shockwave propagation speed and time headway is presented.
  Authors: Stanitsas, Panagiotis D; Stephanedes, Yorgos J.
  Authors: Stanitsas, Panagiotis D; Stephanedes, Yorgos J.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1075
• Multivariate Spatial Models of Excess Crash Frequency at Area Level: Case of Costa Rica
  Abstract: Recently, areal models of crash frequency have being used in the analysis of various area-wide factors affecting road crashes. On the other hand, disease mapping methods are commonly used in epidemiology to assess the relative risk of the population at different spatial units. A natural next step is to combine these two approaches to estimate the excess crash frequency at area level as a measure of absolute crash risk. Furthermore, multivariate spatial models of crash severity are explored in order to account for both frequency and severity of crashes and control for the spatial correlation frequently found in crash data. This paper aims to extent the concept of safety performance functions to be used in areal models of crash frequency. A multivariate spatial model is used for that purpose and compared to its univariate counterpart. Full Bayes hierarchical approach is used to estimate the models of crash frequency at canton level for Costa Rica. An intrinsic Multivariate Conditional Autoregressive model is used for modeling spatial random effects. The results show that the multivariate spatial model performs better than its univariate counterpart in terms of the penalized goodness-of-fit measure Deviance Information Criteria. Additionally, the effects of the spatial smoothing due to the multivariate spatial random effects are evident in the estimation of excess equivalent property damage only crashes.
  Authors: Aguero-Valverde, Jonathan
  Authors: Aguero-Valverde, Jonathan
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-1061
• Multimodal Macroscopic Fundamental Diagram for “Car-Bus” Mixed Traffic Signalized Corridors: Application in City of Barcelona, Spain
  Abstract: This research focuses on the macroscopic modeling of multimodal systems. Specifically, we investigate the existence of macroscopic relations in the Barcelona urban traffic system, including mixed-traffic (bus-car lanes or individual bus-only lanes) and we propose solutions to improve mobility. We study how the throughput of passengers and vehicles depends on the operational characteristics of the system, the level of congestion and the interactions between different modes of transport. Using a microscopic simulator, we investigate the effect of a new high performance bus network (HPB) in the city of Barcelona and we intent to understand macroscopically which is the overall performance of the city as the demand and operational characteristics of each mode changes. Varying different traffic parameters such as traffic demand for private vehicles, frequency and dwell times of buses at each stop are analyzed. We also examine how a congested city center (with a direct application in the city of Barcelona) could reduce its private vehicle demand, by transferring it to public transport and which will be the advantages in term of total delays improvement as a function of demand shift. Our results show that significant benefits can be obtained even in cases frequency of buses (and therefore interactions with vehicles) increase.
  Authors: Geroliminis, Nikolas; Danés, Jordi; Estrada, Miquel Ángel
  Authors: Geroliminis, Nikolas; Danés, Jordi; Estrada, Miquel Ángel
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1089
• Cooperative Traffic Management Policies for Mixed Freeway and Urban Networks
  Abstract: In this paper, the macroscopic traffic modeling and control of a large-scale mixed transportation network consisting of a freeway and an urban network is tackled. The urban network is partitioned into two regions, each one with a well-defined macroscopic fundamental diagram (MFD), i.e. a unimodal and low-scatter relationship between network density and outflow. The freeway is regarded as one alternative commuting route which has one on-ramp and one off-ramp within each urban region. The urban and freeway flow dynamics are formulated with the tool of MFD and asymmetric cell transmission model, respectively. Four controllers are considered to control the flow distribution between the urban regions and the freeway: (i) two on the border of the urban regions operating to manipulate the perimeter interflow between the two regions, and (ii) two other controllers on the on-ramps for ramp metering to control the flows from the urban regions to the freeway. The optimal traffic control problem for the mixed network is solved by a model predictive control approach in order to minimize total delays in the network. Several control policies with different levels of urban-freeway control coordination are introduced to scrutinize the characteristics of the proposed controllers. The results of this paper can be extended to implement efficient real-world control strategies for large-scale mixed traffic networks.
  Authors: Ramezani, Mohsen; Haddad, Jack; Geroliminis, Nikolas
  Authors: Ramezani, Mohsen; Haddad, Jack; Geroliminis, Nikolas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1094
• The Lighthill-Whitham-Richards model for a platoon of vehicles
  Abstract: With the adoption of advanced vehicular technologies, vehicles become more heterogeneous in their driving characteristics, and a traffic stream can be viewed as platoons of regular vehicles led by technology-equipped vehicles. In this study we develop the Lighthill-Whitham-Richards (LWR) model for a platoon of vehicles and solve the Riemann problem at the moving boundary defined by the platoon head. From the Riemann solutions we derive a new supply function in the platoon head's speed. We then propose a modified Godunov method for solving the platoon LWR model numerically. With examples we demonstrate that numerical solutions converge and are consistent with theoretical ones. The model can be used as a fundamental building block for developing hybrid traffic flow models and for studying the moving bottleneck problem on multi-lane roads. This study could lead to better strategies for simulating, estimating, and controlling heterogeneous traffic flow.
  Authors: Jin, Wen-Long; Yang, Hao
  Authors: Jin, Wen-Long; Yang, Hao
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-1097
• Redistribution of Urban Road Space for Multimodal Congested Networks with Macroscopic Fundamental Diagram Representation
  Abstract: Transport systems in real cities are complex with many modes of transport sharing and competing for limited road space. There is an increasing need to understand how space distributions for modes affect traffic performance. While the connection between performance of transport systems and general land allocation is the subject of extensive research, space allocation for interacting modes of transport is an open research question. Quantifying the impact of road space distribution on the performance of a congested multimodal transport system remains exclusive. In this paper, a multimodal macroscopic fundamental diagram (MFD) is developed to represent the traffic dynamics of a multimodal transport system. Optimization is performed with the objective of minimizing the total passenger hours travelled (PHT) to serve the total initial demand by redistributing road space among modes. We find by an application to a bi-modal two-region city that (i) the proposed model captures the operational characteristics of each mode, and (ii) optimal dynamic space distribution strategies to maximize network throughput can be developed. This approach contributes in the research gap of modeling traffic dynamics of multimodal system and of allocating optimal space for modes of transport. In practice, the approach can serve as a tool to inform space distribution strategies for policy makers with different goals of mobility.
  Authors: Zheng, Nan; Geroliminis, Nikolas
  Authors: Zheng, Nan; Geroliminis, Nikolas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1211
• 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
• Assessment of Different Design Hours for Freeways
  Abstract: Conventional methods for the level-of-service assessment on freeways are based on the analysis of one specific peak hour. In Germany, like in many other countries, the 30th hour is defined as the design hour, which means that the 30th highest hourly traffic demand arising during one year is used as input value for freeway design. The paper analyzes the impact of different design hours on the level-of-service assessment for basic freeway segments. Based on traffic data from 50 freeway sections in Germany, the extent of congestion over a whole year is estimated by applying a macroscopic simulation model. With the model, all travel time losses due to congestion can be related to the hours in which the congestion was caused. It is found that on freeways with mainly recreational traffic, most time losses are caused within the first 30 hours, whereas on freeways with mainly commuter traffic, considerable time losses occur even beyond the 100th hour. Thus, the choice of a specific design hour in the range between the 30th and the 100th hour does not significantly affect the assessment results.
  Authors: Geistefeldt, Justin; Hohmann, Sandra
  Authors: Geistefeldt, Justin; Hohmann, Sandra
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-1151
• Macroscopic Travel Time Reliability Diagrams for Freeway Networks
  Abstract: Travel time reliability is considered to be one of the key indicators of transport system performances. The knowledge on the mechanisms of travel time unreliability enables the derivation of explanatory models with which travel time reliability could be predicted and utilized in traffic management. Inspired by the Macroscopic Fundamental Diagram (MFD), describing the relationship between production (average flow completing their trips) and vehicle accumulation (average density) in a traffic network, this paper investigates a so-called Macroscopic travel time (un)Reliability Diagram (MRD), relating the travel time (un)reliability to the network accumulation. The potential of the MFD relation lies in the fact that it characterizes the state of an entire traffic network with just two (production, accumulation) or three (adding spatial variability of accumulation) state variables. Likewise, the MRD describes the network travel time reliability as a function of just one independent state variable (network accumulation). Empirical analyses are performed to investigate the variability in MFD as seen in scatters and to show the travel time (un)reliability in relation to the network accumulations. Traffic data from Dutch freeway networks are employed to facilitate the analyses. It is found with the MRD on different freeway networks that a critical travel time (un)reliability accumulation exists, below which network accumulation has little or even no impacts on travel time (un)reliability and above which the accumulation has significant impacts on travel time (un)reliability. It is also found that the critical travel time (un)reliability accumulation is in general lower than the critical MFD accumulation. These findings provides insights for the road authorities in how to make tradeoffs between the maximum production and the travel time reliability in traffic management.
  Authors: Tu, Huizhao; Li, Hao; Van Lint, Hans; Knoop, Victor L.; Sun, LiJun
  Authors: Tu, Huizhao; Li, Hao; Van Lint, Hans; Knoop, Victor L.; Sun, LiJun
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-1123
• ON TRAFFIC SAFETY HAZARDS IN EVACUATIONS DUE TO CHANGES IN DRIVING BEHAVIOR
  Abstract: Real-life observations as well as driving simulator experiments have shown how driving behavior under mentally demanding conditions, such as during an evacuation, differs in certain aspects from that at normal traffic conditions. In this paper, we continue with these findings by investigating how these differences in driving behavior have an impact on traffic safety. For this, the microscopic simulation framework S-Paramics is adapted accordingly, and applied to the evacuation network of the Dutch city of Almere. This experimental setup allows a structured and in-depth analysis of the relationship between a number of driving behavior parameters and the emergent traffic safety, which are quantified by four different safety indicators based on the well-reported time-to-collision value. Where earlier studies conclude that a reduction in mean time headway and minimum gap acceptance substantially improves the overall evacuation time, here it is found to also result in more traffic safety hazards, potentially leading to actual traffic accidents that in turn may obstruct the evacuation progress. Furthermore, traffic safety is shown to decline over time, resulting in (substantially) less safe conditions for those who depart later. With these model results and findings, the accompanying discussions and conclusions are insightful and have direct implications for evacuation planning and control practices.
  Authors: Tu, Huizhao; Li, Hao; Pel, Adam J.; Sun, LiJun
  Authors: Tu, Huizhao; Li, Hao; Pel, Adam J.; Sun, LiJun
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-1124
• Variables Influencing Speed Distribution on Urban Arterials and Collectors
  Abstract: Speeds are affected by several variables such as driver characteristics, vehicle performance, road geometrics, environmental conditions and driving regulations. A knowledge of the relationship between speed and such variables allows conscious speed management on existing and planned roads, with the aim of compelling drivers to select a speed consistent with the posted speed limit. This relationship is of great interest to those who wish to achieve roadway functionality and improve overall safety.Focusing on this objective, some contributions concerning urban roads are already available in literature with the caveat that they can be applied only to specific road types and recently built-up areas. Moreover, they refer mainly to the 85th percentile of speed. Lastly, they can only be applied in locations which are homogeneous in terms of geometry, environment, driving regulations and vehicle type.The research aims to establish the correlation between roadway features and operating speed by elaborating new models for the urban environment. The paper presents the results of an investigation carried out on Italian urban arterials and collectors within the municipality of Torino (Italy). The fact that this area is characterized by dissimilar geometric features facilitated the inclusion and study of a fully representative range of variables. Models were calibrated by combining the complete dataset and disaggregating it for the different road typologies. The results showed that, when consideration was given to all the selected variables, certain variables were found to be ever present and statistically significant across all models.
  Authors: Bassani, Marco; Dalmazzo, Davide; Marinelli, Giuseppe
  Authors: Bassani, Marco; Dalmazzo, Davide; Marinelli, Giuseppe
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 253
  Paper Number: 13-1138
• Analyzing the Impact of Illegal Parking on Performance of Arterial Curbside Bus-Only Lanes: Utilizing Bus Camera Data
  Abstract: In this paper, for the first time, recorded videos from bus cameras are used as a new type of transportation data to identify the impact of illegal parking on the performance of peak hour curbside bus-only lanes in Tokyo, Japan. We found that even a few illegally parked vehicles could still significantly influence the performance of a bus lane, especially when it is parked near a bus stop. A microscopic traffic simulation is also carried on to evaluate quantitatively the possible improving strategies, such as stricter enforcement, on the basis of the results obtained by the bus camera data.
  Authors: Wang, Rui; Nakamura, Fumihiko; Okamura, Toshiyuki; Tanaka, Shinji
  Authors: Wang, Rui; Nakamura, Fumihiko; Okamura, Toshiyuki; Tanaka, Shinji
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 807
  Paper Number: 13-1146
• 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
• Geographic Energy Adaptive Potential of Farmers’ Market System as Compared with Conventional Supermarket System
  Abstract: Geographic energy adaptive potential is a quantitative assessment of the capacity of the supply chain system to deliver the same goods using less energy. Issues of oil supply and carbon emissions motivate the study of the energy adaptive potential of the Farmers’ market and supermarket food distribution systems. Three key indicators are used to measure the adaptive potential of the system, 1) systems’ fuel intensity and traceability of products in the supply chain, 2) potential for freight consolidation, 3) access to stores by potential customers. A method is presented to compute the freight energy intensity using information on product origins, number and type of delivery vehicles and amount of goods delivered. A hypothetical freight logistical consolidation model is created to determine potential energy savings. Access to Farmers’ markets and supermarkets by customers is calculated using Service Area analysis of ArcGIS10 and is a function of the geographic elements such as road network infrastructure and census information. The Farmers’ market system in the New Zealand setting was assessed using the three key indicators prescribed. Results of the survey conducted have shown that Farmers’ markets have higher freight energy-intensity than supermarkets. The energy intensity values for the latter were obtained using figures from government-commissioned reports. Consolidation of freight in the Farmers’ market could decrease the energy intensity. However given the current volumes of goods sold at the market, the Farmers’ market would still be more energy-intensive than supermarkets. There is also no difference between access of customers to Farmers’ markets and supermarkets.
  Authors: Asuncion, Janice Sy; Krumdieck, Susan; Rendall, Stacy; Page, Shannon; Murray, Rua
  Authors: Asuncion, Janice Sy; Krumdieck, Susan; Rendall, Stacy; Page, Shannon; Murray, Rua
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1158
• Using Variable Speed Limits for Motorway Off-ramp Queue Protection
  Abstract: Motorway off-ramps are a significant source of traffic congestion and collisions. Heavy diverging traffic to off-ramps slows down the mainline traffic speed. When the off-ramp queue spillbacks onto the mainline, it leads to a major breakdown of the motorway capacity and a significant threat to the traffic safety. This paper proposes using Variable Speed Limits (VSL) for protection of the motorway off-ramp queue and thus to promote safety in congested diverging areas. To support timely activation of VSL in advance of queue spillover, a proactive control strategy is proposed based on a real-time off-ramp queue estimation and prediction. This process determines the estimated queue size in the near-term future, on which the decision to change speed limits is made. VSL can effectively slow down traffic as it is mandatory that drivers follow the changed speed limits. A collateral benefit of VSL is its potential effect on drivers making them more attentive to the surrounding traffic conditions, and prepared for a sudden braking of the leading car. This paper analyses and quantifies these impacts and potential benefits of VSL on traffic safety and efficiency using the microsimulation approach.
  Authors: Lee, Jinwoo (Brian); Qian, Gongbin; Chung, Edward; Miska, Marc Philipp
  Authors: Lee, Jinwoo (Brian); Qian, Gongbin; Chung, Edward; Miska, Marc Philipp
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-1165
• Modified Wall-Building-Based Compound Approach for Container Loading Problem
  Abstract: Efficient loading of containers would raise current productivity for the shipment of mixed, boxed cargo and this paper considers the knapsack container loading problem. Given a rectangular-shaped container, rectangular-shaped boxes with different sizes are packed such that total loaded volume is maximized. All boxes with the same origin-destination pair may be rotated in six orthogonal directions without load-related and positioning constraints. The modified wall-building based compound approach performs 36 modified wall-building heuristics based on three existing ranking functions, two existing priority rules and six orthogonal rotations of containers, while recording the best solution. The six orthogonal rotations of containers are equivalent to filling the container in six ways (four wall building methods and two floor building methods). Three weakly heterogeneous real-world test problems from a furniture company in Thailand are employed. There is not a winning heuristic that performs best on the three test problems. The typical wall-building approach (type-1 container rotation) does not perform well when compared with considering all six orthogonal rotations of container. In terms of the number of containers, the proposed compound approach can save up to 33% on the three test problems, and the highest fill percentages in the best solution founds are improved by up to 36%, when compared with the manual solutions. The proposed approach outperforms the existing tree heuristic. The highest fill percentages by the proposed approach are up to 6% higher than those by the tree search heuristic, whereas the CPU times by the proposed approach are up to 31% of those by the tree search heuristic.
  Authors: Karoonsoontawong, Ampol; Heebkhoksung, Krongthong
  Authors: Karoonsoontawong, Ampol; Heebkhoksung, Krongthong
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1171
• 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
• A Strategic Rail Network Optimization Model for Freight Transportation
  Abstract: The rail freight network optimization model presented in this paper was developed as a support tool for planning and policy decisions involved in the improvement of rail networks on a regional and national level. It is based on a strategic traffic assignment model designed to model macro networks with a high aggregation level, being exclusively designed for freight traffic. The model contemplates road and rail transport modes, and considers two different types of cargo: intermodal cargo, which is generally transported in containers and is easily interchanged between different modes at intermodal terminals; and general cargo, which represents all the remaining cargo. The optimization process is based on a local search heuristic which delivers good solutions in a reasonable computing time, with the quality of each network improvement solution being assessed based on the reduction of the total generalized costs and CO2 emissions. This freight network optimization model is innovative in the fact that it is not limited, allowing for both the improvement of existing links as well as the construction of new ones, and not having a limit on the number or variety of network improvement possibilities. Its adaptability to different conditions is emphasized when the model is applied to two networks under different investment scenarios, by delivering considerably different solutions adapted to the conditions of each scenario.
  Authors: Maia, Luis Couto; Couto, António Fidalgo
  Authors: Maia, Luis Couto; Couto, António Fidalgo
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1177
• Relation Between Distance and Time in Traffic Control: Consequences for Information and Communications Technology Architecture
  Abstract: Congestion is a major problem in large urbanised areas. Intelligent Transport Solutions aim to reduce this problem. Generally, traffic is monitored using sensors, this data is processed, a traffic state is estimated and a control measure is computed and implemented. The availability and quality of the data and the processing time of the algorithms are possible limiting factors in this pattern. This paper investigates what the data requirements for different traffic control measures are. In particular, we focus on the relationship between the spatial scale of the control measure and the time delay between the measurement and the control action, the latency. A set of 17 applications shows that the larger the spatial scale of the control measure, the larger the latency can be.his relationship can be used to determine the latency quality criteria for a certain application. On the other hand, it can be analysed which type of applications are possible when data with a specific quality can be collected. The latter analysis is carried out for a province in the Netherlands. This analysis furthermore shows the difference between the availability in terms of ICT systems and useful data for applications. In particular, if no vehicles pass, the ICT systems are available, but no realistic measurements is produced.
  Authors: Knoop, Victor L.; Van Lint, Hans; Vries, Jasper; Leon, Kester; Passchier, Igor
  Authors: Knoop, Victor L.; Van Lint, Hans; Vries, Jasper; Leon, Kester; Passchier, Igor
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-1199
• Delivering Bus Arrival Information at Stops via Quick Response Codes: Case Study of User Take-up and Reaction in Southampton, United Kingdom
  Abstract: Real-time passenger information systems for bus users are now common place with bus stops in major UK cities equipped with arrival countdown displays and several apps now providing similar information direct to the Smartphone. Real-time displays at stops are expensive to install and given the current rate of smartphone take up, there could be benefits from using Quick Response (QR) codes linking to adapted, mobile friendly, webpages displaying arrival times of buses. This paper reports on a QR code implementation trial on 44 bus stops in six distinct areas of Southampton, UK. Each bus stop was fitted with a poster containing a unique QR code, linking to a website giving live bus arrival information taken from the Southampton traffic control centre. Two types of poster were developed (simplistic with minimal text and a more comprehensive one) to understand what level of instruction was necessary for QR code use. The number of hits at each stop were monitored via the website and surveys of users were undertaken through an on-line questionnaire (accessed via the QR code) and face-to-face interviews.The results suggested that there was very little variation in use of QR codes at stops by day of the week or between peak and inter-peak times but there were variations by geographical area. QR code use improved wait time acceptability and feelings of safety and well-being with the vast majority of users finding the system easy to use.
  Authors: Gammer, Nick; Cherrett, Tom; Gutteridge, Christopher
  Authors: Gammer, Nick; Cherrett, Tom; Gutteridge, Christopher
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 470
  Paper Number: 13-0975
• Impact of Abandoned and Disabled Vehicles on Freeway Incident Durations
  Abstract: In most cases, abandoned and disabled vehicles are left within the roadway right of ways. It is common to find a vehicle left on the shoulder, median, gore area or on the travel lane for certain period of time. Experience from the state of Tennessee has shown that 78% of the freeway traffic related incidents are due to disabled and abandoned vehicles. It is hypothesized that the longer the vehicle is left unattended within the right of way, the higher the probability of new incidents and secondary crashes. This paper utilized 2004 to 2010 freeway incident data in Tennessee to evaluate the impact of the length of incident durations caused by disabled and abandoned vehicles. Analysis evaluated the impact of these incidents with respect to roadway location, queue lengths, weather conditions, towing times, lane closure, and the source of incident notification. Temporal factors, including the spectra of the time of the day, the day of the week, and the seasons of the year were evaluated with respect to the number of incidents and incident durations. It was found that vehicles left on the left and right shoulders generated more incidents compared to other locations followed by gore areas and the ramps. Parametric hazard based log-logistic survival model was applied to determine the factors affecting the abandoned and disabled vehicles incident duration. Number of closed lanes, length of the queue formed, construction zones, trucks and towing involvement were found to be significantly associated with longer incident duration.
  Authors: Chimba, Deo; Kutela, Boniphace; Ogletree, Gary; Horne, Frank; Hallavant, Raymond
  Authors: Chimba, Deo; Kutela, Boniphace; Ogletree, Gary; Horne, Frank; Hallavant, Raymond
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 337
  Paper Number: 13-1065
• Integrated Approach for Work Zone Planning in Pavement Maintenance of High Traffic Roads
  Abstract: In the context of project level pavement management, planning maintenance and rehabilitation interventions on roads tends to be a complex process, particularly whenever high traffic flows are present. This paper describes a methodology developed in order to support the decision-maker while planning this type of interventions. The methodology relies on two key stages. At first, a computer model generates the set of feasible options concerning working plant layouts and schedules, and combines them in order to include all the options for the intervention’s planning and undertaking. It takes in consideration, besides other elements, the type of maintenance or rehabilitation intervention to be carried out, traffic characterization and site features. There are three different attribute types intended to characterize each alternative of the intervention: agency cost, works’ duration and the delay faced by users. Each intervention can be evaluated in such a way that the decision-maker may obtain a set of feasible and established alternatives. Subsequently, a multiple-criteria decision model is used to compare all the alternatives included in the previously obtained set using to the mentioned criteria (cost, duration and delay) according to the weights that correspond to the decision-maker preferences. The capabilities of the described methodology are illustrated by two case studies corresponding to two freeway stretches located in the Lisbon Metropolitan Area where a standard intervention is considered. The computation of the feasible alternatives set for the intervention allowed the comparison between them, based on the mentioned attributes and, consequently, on the results of the multiple-criteria decision model.
  Authors: Morgado, João; Neves, José
  Authors: Morgado, João; Neves, José
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 339
  Paper Number: 13-1210
• Effect of Left Turns for Arterials with Queue Spillbacks
  Abstract: Traditional capacity calculation of signalized intersections does not take into account the effects of queue spillbacks that might occur at left-turn approach with two-lane section, i.e. an approach with one shared lane that expands to through movement and left turn lanes before the stop line at the intersection. As demand of the left-turn increases, and the storage capacity of the left-turn bay is limited, the probability of queue spillback occurrence increases. This is also correct for the through movements at its queue might also spillback to the shared-lane section. In this paper, we model the effects of queue spillbacks at the left-turn approach (both spillback from left-turn and through movements) on the capacity of the intersection, and as a result we also calculate the capacity drop. Afterwards, we extend our model to calculate the capacity of arterials with number of signalized intersections experiencing queue spillbacks at downstream approaches with two-lane section. Case study examples examine the effect of intersection characteristics (e.g. left-turn percentage, green durations, and storage capacity) on the arterial capacity drop. Finally, different left-turn control policies related to prohibit or permit left-turns at intersections are examined to increase the capacity of arterials. These control polices can help the traffic engineer practitioners not only to increase the capacity, but also to allocate efficiently the gained space from preventing left-turn to other transportation mode, e.g. bus lanes.
  Authors: Haddad, Jack; Geroliminis, Nikolas
  Authors: Haddad, Jack; Geroliminis, Nikolas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-1212
• Safety Effects of Access Points near Signalized Intersections
  Abstract: According to the National Highway Traffic Safety Administration (NHTSA), every year over five million collisions occur in the US. More than half of these collisions are intersection and access point-related. The main objective of this research was therefore to develop a valid statistical model to estimate the number of access point-related collisions occurring at access points near signalized intersections.Geometric, traffic, and point-related collision data over 5 years, from January 2005 to December 2009 were collected for 108 sites. The average annual daily traffic (AADT) and 14 more independent variables were introduced into the model one by one in a multiplicative form. The final model was selected based on NLMIXED, a nonlinear optimization method, in SAS® to estimate the model parameters and the -2 Log Likelihood and Bayesian information criterion (BIC) statistical criteria. Finally cumulative residual (CURE) plots were used to check the goodness of fit of each model.Out of the 15 independent variables tested, only AADT, driveway width, and through movement queue at the intersection near the access point were statistically significant in developing the collision prediction statistical model. This model could be used by state DOTs and municipal traffic engineers to address access management requirements and to predict problems likely to result from site traffic impacts.
  Authors: Jafari, Reza; Hummer, Joseph E.
  Authors: Jafari, Reza; Hummer, Joseph E.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Deploying Transportation Research-Doing Things Smarter, Better, Faster
  Session: 672
  Paper Number: 13-1218
• Statistical characterization of vehicles in 2-lane roads in Spain.
  Abstract: Two-lane roads are not easy to model. Macroscopic models omit the queue structure, essential for characterizing the level of service. Microscopic models are more adequate, but in practical terms they can be considered inadequate, since they require the introduction of data unavailable for most areas. This paper seeks to provide information to improve the use of microscopic models, in particular for the Madrid Region.Traditional vehicle types are passenger cars, trucks, buses and motorcycles. However, it is clear that congestion is caused by heavy vehicles, but also by slower cars, both having lower desired speeds. These slower vehicles can travel isolated or as platoon leaders.This paper focuses on the speed distributions of different vehicle types and queue structure, to establish measurement procedures and what errors arise from considering isolated vehicles or queue leaders. It also provides statistical information on desired speed distributions and day and nighttime driving in two-lane roads in the Madrid region. A new isolated vehicle criterion is proposed, allowing less restrictive conditions and larger sample sizes. Other conclusions are established regarding the inclusion of all platoon leaders in design speed considerations, and whether different populations can be established regarding queue length behind a vehicle.
  Authors: Castilla, Guillermo; Romana, Manuel G.
  Authors: Castilla, Guillermo; Romana, Manuel G.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-1025
• Study on Relationship Between Font Height of Text Markings and Legibility Distances
  Abstract: Pavement marking symbols (such as text markings, symbol markings and arrow markings) are an important part of the traffic guide sign system. In large passenger transport hubs, pavement marking symbols can play an important role in guiding the flows of passengers. This research used field pavement text markings to analyze the relationship of the font height of text markings and the legibility distances. This research employed analysis of variance and difference of means test to identify the factors that affect the legibility distances. A regression model was developed to describe the relationship between the font height of text markings and the legibility distances. Based on this model, a variety of text marking design recommendations can be drawn, to improve the legibility and effectiveness of text pavement markings.
  Authors: Wang, Kewen
  Authors: Wang, Kewen
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-1270
• Global Optimization Approach for Combined Traffic Assignment and Signal Control
  Abstract: This paper proposed a global optimization method for solving the combined traffic assignment and signal control problem. Conventionally, the problem is formulated into a bi-level program: the upper-level describes the constraints of signal variables and minimize the performance index of the system, whereas the lower-level represents the equilibrium flow pattern. It is well known that bi-level program is non-linear and non-convex and it is hard to find the global optimization solution. In this article, we present a global optimal method to solve this problem. Firstly, we transform the bi-level program into a single-level program. Then, we implement an efficient mixed-integer model referred as DLog (Logarithmic disaggregated convex combination model) to linearize and approximate the non-linear constraints by piece-wise linear functions. Finally, the bi-level program is cast into a mixed-integer linear model, which can be easily solved by commercial mixed-integer program solver and thus the global optimal solution can be guaranteed. In numerical studies, the application of the method are demonstrated by a small network and compared with the results reported in the literature.
  Authors: Wang, David Zhiwei; Liu, Haoxiang
  Authors: Wang, David Zhiwei; Liu, Haoxiang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1443
• 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
• From Theory to Practice: Gaussian Process Meta-Models for Sensitivity Analysis of Traffic Simulation Models: Case Study of Aimsun Mesoscopic Model
  Abstract: This paper discusses a metamodel-based technique for model sensitivity analysis and applies it to the Aimsun mesoscopic model. Throughout the paper it is argued that the application of sensitivity analysis is crucial for the true comprehension and correct use of the traffic simulation model while also acknowledging that the main obstacle to an extensive use of the most sophisticated techniques is the high number of model runs they usually require.For this reason we have tested the possibility of performing sensitivity analysis not on a model but on its metamodel approximation. Important issues arising when estimating a metamodel have been investigated and commented on in the specific application to the Aimsun model. Among these issues is the importance of selecting a proper sampling strategy based on low discrepancy random number sequences and the importance of selecting a class of metamodels able to reproduce the inputs-ouputs relationship in a robust and reliable way. Sobol sequences and Gaussian process metamodels have been recognized as the appropriate choices.The proposed methodology has been assessed by comparing the results of the application of variance-based sensitivity analysis techniques to the simulation model and to a metamodel estimated with 512 model runs, on a variety of traffic scenarios and model outputs. Results confirm the powerfulness of the proposed methodology and also open up to a more extensive application of sensitivity analysis techniques to complex traffic simulation models.
  Authors: Ciuffo, Biagio Filippo; Casas, Jordi; Montanino, Marcello; Perarnau, Josep; Punzo, Vincenzo
  Authors: Ciuffo, Biagio Filippo; Casas, Jordi; Montanino, Marcello; Perarnau, Josep; Punzo, Vincenzo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 769
  Paper Number: 13-1533
• Evaluation of Driver Perception-Reaction Times for Rainy and Wet Roadway Conditions at Onset of Yellow Indication at Signalized Intersections
  Abstract: The research presented in this paper characterizes the impact of wet pavement surface and rainy weather conditions on driver perception-reaction times (PRT) at the onset of a yellow indication on high-speed signalized intersection approaches in a controlled field environment using an in-vehicle differential Global Positioning System (GPS). A total of 384 data records were available for analysis for all drivers who stopped at the onset of the yellow indication, ranging from a minimum time-to-intersection (TTI) of 2.35 s to a maximum of 5.71 s. Statistical analyses were used to quantify the effects of the TTI, grade (uphill and downhill), gender, and age (under 40-years-old, 40 to 59-years-old, and 60 years of age or older) on driver PRTs.The study demonstrates that a driver PRT increases with a TTI increase. A longer PRT was found when vehicles travel along an upgrade section given that the driver is typically accelerating when the yellow indication is initiated. No gender differences were found in PRTs. Also, no statistically significant differences were found between different age groups. Furthermore, the study demonstrates that driver PRTs increase on wet pavement surface and rainy weather conditions when compared to clear weather conditions over the entire TTI range.
  Authors: El-Shawarby, Ihab; Abdel-Salam, Abdel-Salam Gomaa; Rakha, Hesham
  Authors: El-Shawarby, Ihab; Abdel-Salam, Abdel-Salam Gomaa; Rakha, Hesham
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-1683
• Safety Analysis of Suburban Arterials in Shanghai, China
  Abstract: As urban sprawl continues to accelerate in China, more lands are developed along suburban arterials and more people use these roads to commute. This necessarily results in an increase of access points appearing along the suburban arterials, which lead to a raise of traffic safety hazardous. This safety problem requires in-depth analysis to better understand the relationship between roadway design, traffic operation and traffic safety. This study examined a total of 161 roadway segments (each between two adjacent signalized intersections) on eight different suburban arterials in Shanghai. Geometric design features, access point information, and traffic flow characteristics for chosen 161 segments were collected. A preliminary inspection of the data revealed that roadway segments from the same arterials share similar geometry, access and traffic flow characteristics. To account for the spatial correlation, Bayesian Hierarchical models were developed to identify the safety factors at both arterial and segment levels. Three hierarchical Negative Binomial (HNB) models were developed for slight crashes, severe crashes and total crashes. Model comparisons between HNB models and Negative Binomial models have affirmed the existence of spatial correlation. Results showed that the density of signal spacing along arterial (DOSP) on arterials has a significant influence on the three types of crashes frequencies. The non-uniform signal spacing has a significant impact on of the occurrence of slight crashes. At the segment-level, higher frequencies of slight crashes, severe crashes and total crashes tend to occur for the segments in inner suburban areas with curves, the segments with a higher density of access points, and the segments with higher percentage of large-size vehicles. The safety impacts of different variables of traffic composite were also studied.
  Authors: Wang, Xuesong; Song, Yang; Huang, Helai
  Authors: Wang, Xuesong; Song, Yang; Huang, Helai
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Deploying Transportation Research-Doing Things Smarter, Better, Faster
  Session: 672
  Paper Number: 13-1727
• Making NGSIM Data Usable for Studies on Traffic Flow Theory: Multistep Method for Vehicle Trajectory Reconstruction
  Abstract: Despite the undoubted importance of NGSIM data for the research on traffic flow theory, they were proved to be massively affected by measurement errors in the spatial coordinates of the vehicle, further amplified in the differentiation process when calculating speeds and accelerations. If not properly accounted for, these errors would make NGSIM data not usable for any study on traffic flow theory. However, we argued herein that the techniques applied so far in the literature to correct vehicle trajectory data are not suitable for the scope, as they did not treat appropriately the “cause” of the bias, while limited to smooth out the “effects”, that are the high and medium frequency disturbances in the data.Therefore, in this paper we first illustrated the mechanism at the basis of the errors in the NGSIM data, and showed the limits of currently available techniques. Secondly we clarified that extremely high errors, the outliers, need a special treatment to be fixed. In this light, we presented a multi-step filtering procedure aimed at i) eliminating the outliers that give rise to unphysical values for the acceleration by the local reconstruction of the vehicle trajectory, and ii) cut-off the residual random disturbances from the signal, still preserving the driving dynamics (vehicle stoppages, shifting gears, etc.). Both the operations were performed taking directly into account the requirement for internal consistency of the trajectory, that is the consistency among space travelled, speeds and accelerations.Though the procedure is absolute general, and can be applied to whatever vehicle’s trajectory, in this paper we first presented the results related to a single vehicle’s trajectory from NGSIM I80 dataset, and, then, those from the application to the complete set of trajectories from the same dataset. Results here presented motivated the need to correct NGSIM data before any further processing.
  Authors: Montanino, Marcello; Punzo, Vincenzo
  Authors: Montanino, Marcello; Punzo, Vincenzo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1739
• Additional Lost Time due to Downstream Queue at Closely Spaced Intersections
  Abstract: At closely spaced signalized intersections, additional lost time can occur at upstream intersections when there is a queue spillback as a result of suboptimal signal timing. Closely spaced intersections are commonly seen at signal-controlled interchanges like diamond interchanges and partial cloverleaf interchanges. For a better estimation of capacities of closely spaced intersections, it is necessary to have an accurate model to calculate the additional lost time. The Chapter of Interchange Ramp Terminals in the Highway Capacity Manual 2010 provides a model for estimating additional lost time due to the presence of a downstream queue at closely spaced intersections. However, the HCM model does not provide a very accurate estimation when the distance to the downstream queue is short. In this paper, a new model is developed for an accurate estimation of additional lost time at closely spaced intersections, considering different factors that are not addressed in the HCM model or in previous research, like queue discharge pattern and traffic flow patterns. Simulation results indicate that the new model provides a more accurate estimation of additional lost time compared with HCM model in conditions when the distance to the downstream link is limited.
  Authors: Zhang, Zhen; Zong, Tian Z.
  Authors: Zhang, Zhen; Zong, Tian Z.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-1711
• Analysis of Performance Criteria for Model-Based Traffic Congestion Control in Urban Road Networks
  Abstract: Traffic congestion is a serious problem for big cities. Model-based optimization control strategy is an effective method to decrease traffic congestion. A proper control performance criterion is akey factor for effectively addressing different urban road network issues, e.g. the network mobility and the traffic congestion. Therefore, in this paper, we propose two control performance criteria, L^2-norm and L^\infty-norm performance indexes, for model-based urban road network controllers. The L^2-norm and L^\infty-norm performance indexes are aiming at keeping road network homogeneity and decreasing road network congestion respectively. In order to analyze these two control performance criteria, case studies are carried out on the microscopic simulation software CORSIM to evaluate the designed model-based controllers with different criteria. The control effects of the model-based road network controllers are compared quantitatively by analyzing the road network congestion degree, and qualitatively by analyzing the Macroscopic Fundamental Diagram (MFD) of the road network(i.e. a network aggregated characteristic).
  Authors: Lin, Shu; Zhou, Zhao; Xi, Yugeng
  Authors: Lin, Shu; Zhou, Zhao; Xi, Yugeng
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1775
• Road Safety Forecasts in Five European Countries Using Structural Time-Series Models
  Abstract: Modeling road safety development is a complex task, which needs to consider both the quantifiable impact of specific parameters, as well as the underlying trends that cannot always be measured or observed. The objective of this research is to apply structural time series models for obtaining reliable medium- to long-term forecasts of road traffic fatality risk, using data from five countries with different characteristics from all over Europe (Cyprus, Greece, Hungary, Norway and Switzerland). Two structural time series models are considered: (i) the local linear trend model and the (ii) latent risk time-series model. Furthermore, a structured decision tree for the selection of the applicable model for each situation (developed within the DACOTA research project) is outlined. First, the fatality and exposure data that are used for the development of the models are presented and explored. Then, the modeling process is presented, including the model selection process, the introduction of intervention variables and the development of mobility scenarios. The forecasts using the developed models appear to be realistic and within acceptable confidence intervals. The proposed methodology is proved to be very efficient for handling different cases of data availability and quality, providing an appropriate alternative from the family of structural time series models in each country. A concluding section providing perspectives and directions for future research is finally presented.
  Authors: Antoniou, Constantinos; Papadimitriou, Eleonora; Yannis, George
  Authors: Antoniou, Constantinos; Papadimitriou, Eleonora; Yannis, George
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-1786
• Approach for Integrating Sustainability into Roadway Project Development
  Abstract: Efforts to increase the sustainability of roadways continue to gain momentum. In recent years, numerous organizations and agencies have developed sustainability evaluation tools, including third-party rating systems, self-assessments, and checklists, with the goal of evaluating the sustainability characteristics and performance of roadway projects. While these sustainability tools are highly valuable and the result of much research and knowledge, there is little guidance on how to apply and leverage them to best integrate sustainability throughout project development. The focus of this paper, in addition to providing considerations for using sustainability evaluation tools and summarizing the available tools and, is to provide an approach for integrating sustainability into project development by leveraging sustainability evaluation tools.
  Authors: Reid, Lisa M; Davis, Anneke J; Bevan, Timothy
  Authors: Reid, Lisa M; Davis, Anneke J; Bevan, Timothy
  Year: 2013
  Document Type: Paper
  Subject: Construction; Environment; Operations and Traffic Management
  Session: 274
  Paper Number: 13-1772
• Performance Benchmarking of Road Weather Information System Pavement Temperature Forecasts
  Abstract: This paper describes a study focusing on performance evaluation of RWIS pavement temperature forecasts. To identify the factors influencing the accuracy of forecasts, five research hypotheses were constructed that RWIS forecasting accuracy would be affected by climatic patterns (e.g., maritime, continental, and mixed), locational attributes (e.g., geography), seasonal variations (e.g., shoulder months vs. non-shoulder months), time of day (e.g., day vs. night), and forecast horizon. RWIS observations and forecasts data sets provided by four North American provincial transportation agencies were pre-processed and stratified by station, hour, and month, to test the hypotheses and quantify their effects by utilizing two performance metrics, namely mean absolute error (MAE) and percent of acceptable forecasts (PAF). The overall statistics showed that maritime climate group had the highest correspondence and those from mixed climate group had the lowest correspondence, both in terms of their MAEs and PAF. As for the locational attributes, it was found that the forecasting performance of maritime region near coastal areas was found to have a negative correlation with the distance from nearby large water body. It was also found that daytime forecasts were less accurate than the ones generated for night time. Furthermore, the accuracy of forecasts was found to deteriorate quickly as the forecasting horizon increases. Lastly, forecast errors were found to exhibit seasonal variations with forecasts for the shoulder/transitional months tending to be poorer than other months.
  Authors: Kwon, Tae-Jung; Fu, Liping; Perchanok, Max S.
  Authors: Kwon, Tae-Jung; Fu, Liping; Perchanok, Max S.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 603
  Paper Number: 13-1764
• Traffic Flow with Increasing Density Assuming a Simple Safe Stopping Distance Formula
  Abstract: This study investigates the influence of traffic density on traffic flow by assuming a simple safe stopping distance between vehicles. To begin with, vehicles are uniformly spaced onto a highway and all vehicles and drivers' characteristics are identical. Spacing includes the length of the vehicle and a minimum allowable front and back gap. A simple basic-model generates flow values using a safe-stopping-distance (SSDm) formula. Vehicles obey a maximum speed limit. The resulting nearly triangular shaped traffic flow fundamental diagram, FD, is not surprising; however, it reveals the theoretical existence of a third regime between the congested and uncongested regimes. The mathematical description of this regime is formulated. The HighSim-model is a variation on the basic-model. Rather than uniformly spacing the vehicles on the highway, it generates a random location and checks the size of the space for adequacy before placing the vehicle at that location. HighSim also allows for a distribution of values for pertinent parameters. The influence on traffic flow due to the length of the vehicles and the drivers' reaction times are two of the parameters reported here. The research finds that the FD’s third regime becomes more apparent with HighSim. Results indicate that each of the parameters adds a complexity to the basic-model and has its own unique effect on the FD. Finally, traffic flow generated by HighSim compares closely with real data plots.
  Authors: Masoud, Neda; Zarrillo, Marguerite; Gartner, Nathan H.
  Authors: Masoud, Neda; Zarrillo, Marguerite; Gartner, Nathan H.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1765
• Effect of Winter Weather and Road Surface Conditions on Macroscopic Traffic Parameters
  Abstract: This paper presents an empirical study focusing on identifying the main factors that affect the capacity and free-flow-speed (FFS) of urban freeways under inclement winter weather conditions. The weather and road surface condition factors examined include air temperature, wind speed, hourly snow intensity, visibility, snow on ground, and road surface condition describing the road slipperiness caused mainly by snow events. Data on traffic operations, the associated weather and road conditions observed at two freeway locations over the 2010-2012 winter seasons were used in an extensive statistical analysis. Linear regression models were calibrated for both capacity and FFS reductions as related to various weather and road condition variables. It was found that visibility and road surface conditions have a statistically significant effect on both capacity and FFS. Snow intensity was found to be significant only when the visibility factor was excluded, suggesting the presence of confounding of these two factors on capacity and FFS. The modeling results were compared with those recommended by the Highway Capacity Manual 2010, showing that in many cases, HCM could underestimate or overestimate the effects of winter weather conditions and that the proposed models provide more reasonable estimate at a higher level of granularity.
  Authors: Kwon, Tae-Jung; Fu, Liping; Jiang, Chaozhe
  Authors: Kwon, Tae-Jung; Fu, Liping; Jiang, Chaozhe
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 375
  Paper Number: 13-1763
• Modeling Mandatory Lane Changing Using Bayes Classification and Decision Trees
  Abstract: Bayes Classification and Decision Tree methods were applied to model mandatory lane changes. Detailed vehicle trajectory data from the Next Generation Simulation (NGSIM) dataset were used for model development and validation. The results demonstrated higher prediction accuracies for merge and non-merge events compared to a conventional binary Logit model. Furthermore, both models reveal that a merging vehicle’s relative speed with respect to the lead vehicle in the target lane is the most crucial factor drivers take into account while merging. The proposed models can be applied in traffic simulations. Since models are built on pre-congested and congested traffic data, they can improve the ability of microscopic simulation models to realistically simulate saturated and oversaturated traffic conditions that occur near roadway bottlenecks. With some improvements in accuracy, the proposed models can also be used for real-time applications such as driver assistance systems.
  Authors: Hou, Yi; Edara, Praveen; Sun, Carlos
  Authors: Hou, Yi; Edara, Praveen; Sun, Carlos
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1359
• A Review of Lane Change Definitions and Identification Methods
  Abstract: Lane changes are challenging maneuvers and represent an important component of traffic research. Significant efforts have been spent on lane change related research, and various models have been developed to study lane change behavior from different perspectives. In order to identify lane change maneuvers from time series data, researchers have been using different lane change definitions and identification methods, which makes the conclusions drawn from their research dependent on the author’s choice of definition or method. This article reviews lane change definitions and a collection of identification methods, provides a summary of the existing literature and offers information relevant to the selection of a definition or identification method.
  Authors: Xi, Yubin; Crisler, Matthew
  Authors: Xi, Yubin; Crisler, Matthew
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1691
• 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
• Driving Simulator Study of Signing for Complex Interchanges
  Abstract: This paper documents a driving simulator project that identified driver lane changing behavior for six topics related to freeway guide signing at complex interchanges. Forty-two drivers from rural and urban areas of Texas used a desktop driving simulator to navigate fictional destinations by following test guide signs. Driver peformance measures included lane change proximity to interchanges and number of unnecessary lane changes. In addition, subjective measures of comfort and confidence were obtained. Almost all participants made the correct decision to exit or stay on the freeway with an option lane; however, many unnecessary lane changes were made with each of the three sign sets. For the sign set that had an arrow per lane design when signing closely spaced interchanges, all participants made correct lane change decisions. While several incorrect lane changes were made for each sign set used to evaluate signing for a Y split, the sign set that used split exit signs at all three sign bridge locations had the fewest, and was judged superior. The topics that evaluated if it is better to fill an advance single sign with supplemental wayfinding information, or to spread the information among multiple signs found that spreading information about the next exits across multiple signs on a single bridge may have unintended consequences if the sign for another exit is located to the left of the preferred lane. The topic that evaluated driver understanding of left exit signs found minimal difference between the two sign sets tested.
  Authors: Fitzpatrick, Kay; Chrysler, Susan T.; Nelson, Alicia A.; Iragavarapu, Vichika
  Authors: Fitzpatrick, Kay; Chrysler, Susan T.; Nelson, Alicia A.; Iragavarapu, Vichika
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-1682
• Adaptive, Personalized Travel Information Systems: Bayesian Method to Learn Users’ Personal Preferences in Multimodal Transport Networks
  Abstract: Provision of personalized advice is an important objective in the development of advanced traveler information systems. In this paper, we propose a Bayesian method to incorporate learning of users’ personal travel preferences in a multi-modal routing system. Travel preferences are represented by parameters of link costs function the routing system uses to find optimal routes in an integrated multimodal network. Existing sampling-based methods to estimate posterior distributions require too much computation time for the incremental type of learning we are dealing with here. Therefore, we develop an approximation method that is based on sequential processing of parameters and systematic sampling of the parameter space. Data of repetitive travel choices of a large and representative sample of individuals are used to test the system. The results indicate that the system adapts rapidly already on the basis of a few observations from a user and that learning is effective. The efficiency of the algorithm allows the system to handle realistically sized learning problems with short response times even when many users are to be processed simultaneously. We conclude therefore that the approach is feasible and we identify problems for future research.
  Authors: Arentze, Theo A.
  Authors: Arentze, Theo A.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 546
  Paper Number: 13-1325
• Integrating Shared-Use Vehicles: Building the Next Generation of Transit
  Abstract: This paper serves as an introduction to practitioners on shared use vehicles and several strategies to implement and integrate shared use vehicles into an existing transit or transportation network. The shared use vehicles identified are ride sharing, car sharing and bike sharing. The history and current market of each mode is reviewed. The paper includes a review of research of transit integration. The integration methods suggested is integration through street infrastructure, the fare card and information technology. Challenges of each integration method are reviewed and several case studies are explored. A policy implementation chart is included to guide practitioners in municipal government to implement an integrated transportation system that includes shared use vehicles.
  Authors: Alpert, Lauren
  Authors: Alpert, Lauren
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Pedestrians and Bicyclists; Planning and Forecasting
  Session: 559
  Paper Number: 13-1332
• Freeway Path and Multi-Step-Ahead Travel Time Prediction Under Various Weather Scenarios
  Abstract: Accurate and reliable travel time prediction is very much needed for pre-trip planning and implementing traffic control strategies to reduce travel time and relieve traffic congestion. This research proposes an integrated model for path and multi-step ahead travel time prediction on freeways using various sources of real time traffic and weather data. The model’s performance is investigated and reported under various traffic and weather scenarios and especially under inclement weather conditions.
  Authors: Qiao, Wenxin; Haghani, Ali; Hamedi, Masoud
  Authors: Qiao, Wenxin; Haghani, Ali; Hamedi, Masoud
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 546
  Paper Number: 13-1339
• Inhomogeneous Flow Patterns in Undersaturated Road Networks and Implications for Macroscopic Fundamental Diagram
  Abstract: Travel conditions in a road network are described by a Macroscopic Fundamental Diagram, or MFD, only when traffic is homogenously distributed over all of the network’s links. Otherwise, a network’s measured traffic states fall beneath its MFD, and network flow therefore falls below the maximum. The present study finds that inhomogeneities in a network’s link flows may emerge prior to the start of a rush, even before persistent queues have formed. This is potentially problematic because it is known that inhomogeneities of this kind can persist in a network for long durations. Hence, the inhomogeneities that we predict for under-saturated traffic conditions may persist as the network moves to the brink of congestion, and even well beyond. It follows that if drivers are left to their own devices, a network would never serve its rush-period demand at the maximum rate.The finding came by modeling in simple ways the steady-state conditions in under-saturated networks of signalized intersections. Analyses were performed for both, an idealized street grid characterized by uniform O-D patterns, and a more realistic demand pattern that resembles one in downtown San Francisco, California. Emergent patterns in inhomogeneous link flow are examined. Preliminary ideas to combat these undesirable patterns are discussed.
  Authors: Doig Godier, Jean C.; Gayah, Vikash V.; Cassidy, Michael J.
  Authors: Doig Godier, Jean C.; Gayah, Vikash V.; Cassidy, Michael J.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1371
• 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
• Operational Effectiveness of Passing Zones Depending on Their Length and Traffic Volume
  Abstract: Two-lane highways operation has been deeply studied. The HCM proposes the length of no-passing zones as a parameter on the model; however, the distribution and characteristics of the passing zones along the highway are not addressed. This research presents an analysis of the effectiveness of passing zones considering their length and traffic volume. Data were collected on four passing zones of one rural highway in Spain, with two-way traffic volumes ranging from 100 veh/h to 900 veh/h and lengths between 265 and 1,270 m. More than 1,600 passing maneuvers were recorded during 53 hours. Operational effectiveness of passing zones was obtained from passing frequency, as the number of passes per time, and from passing rate, as the number of passes per time and following vehicle. The longer the passing zone is, the higher passing frequency is. However, the effectiveness of passing zones was stabilized from 1,100 m. On the other hand, balanced flows with two-way traffic volumes between 600 and 700 veh/h optimized the number of passes. Nevertheless, passing rate decreased as traffic volume increased. The results were validated with additional 46-hour data from other twelve passing zones.Highway Capacity Manual adjustments on average travel speed and percentage time spent following based on percentage of no-passing zones do not reliably represent effectiveness of passing zones. Effectiveness of every passing zone should be considered instead. Furthermore, the effect of traffic volume on the adjustment factors should be modified to maximize the passing opportunities on traffic volumes between 600 and 700 veh/h.
  Authors: Moreno, Ana Tsui; Llorca, Carlos; Garcia, Alfredo; Perez-Zuriaga, Ana Maria
  Authors: Moreno, Ana Tsui; Llorca, Carlos; Garcia, Alfredo; Perez-Zuriaga, Ana Maria
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-1483
• Using Mobile Probe Data and Macroscopic Fundamental Diagram to Estimate Network Densities: Tests Using Micro-Simulation
  Abstract: Recent advances in urban traffic modeling have led to the proposal of several network-wide control strategies aimed at improving network efficiency. These strategies include limiting vehicle entry through pricing, optimally charging vehicles to enter the network, and optimally allocating limited street space between multiple modes. However, these types of strategies typically rely on accurate predictions of network-wide traffic conditions, and take for granted that these predictions can be obtained in real time. In practice this is not a trivial issue, as measuring traffic conditions across a network typically requires a tremendous amount of data that is usually not available in real time. This paper proposes combining travel speed information from few circulating probe vehicles with a Macroscopic Fundamental Diagram of urban traffic to indirectly estimate network densities in real time. The proposed method is advantageous because it requires little real-time data and involves few calculations. Tests of this methodology on a simulated traffic network show that results are not accurate when the network is uncongested. However, reliable density estimates are obtained when the network is congested or approaching congestion, even if only a small fraction of vehicles serve as probes. This is promising since congested states are the most critical to identify. Thus, this methodology seems particularly useful as a traffic monitoring scheme to complement network-wide traffic control strategies, provided that a well-defined and reproducible macroscopic fundamental diagram exists on the network.
  Authors: Gayah, Vikash V.; Dixit, Vinayak V.
  Authors: Gayah, Vikash V.; Dixit, Vinayak V.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 213
  Paper Number: 13-1493
• Impact of Heavy Vehicles on Freeway Operating Characteristics Under Congested Conditions
  Abstract: The significant impact Heavy Vehicles (HV) have on freeway operations has been identified since the first edition of the Highway Capacity Manual (HCM). HCM 2010 used Passenger Car Equivalent (PCE) values and percent of trucks/buses and Recreational Vehicles (RV) to account for HV effect on roadway performance. Unfortunately, PCE values in the HCM 2010 relied on a limited field database, and simulation runs that were calibrated for steady-flow traffic conditions. On the other hand, the effect of HV on traffic flow can reasonably be expected to vary with traffic conditions. Very few studies have been conducted with extensive field data to examine traffic characteristics impacts due to the presence of HV under congested and forced-flow conditions. This paper presents such an effort by using urban freeway data containing 1.2 million individual vehicle observations. Results indicated a significant difference in Lagging-Leading behavior among vehicle pairs related to HV presence. Passenger Car and HV headways were found to increase with HV presence in the traffic stream. A similar pattern was found for the PCE factor. The PCE value, under congested conditions and more than 9% HV presence, was found to be 1.76, which is higher than the HCM 2010-recommended value of 1.5 for level freeway sections. The results of this paper can be used as input for future simulation runs of congested freeway flow conditions.
  Authors: Ahmed, Umama; Drakopoulos, Alexander; Ng, ManWo
  Authors: Ahmed, Umama; Drakopoulos, Alexander; Ng, ManWo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 337
  Paper Number: 13-1542
• Effect of Countdown-only Pedestrian Change Interval Displays on Signal Recognition by Pedestrians with Reduced Visual Acuity
  Abstract: This study evaluates the effects of visual pedestrian signal displays on the ability of persons with reduced visual acuity to accurately and confidently identify the pedestrian interval. While watching video clips of actual intersections presented on a 42 in. monitor under simulated visual impairment (participants in Experiment 1 experienced simulated acuities of 20/70, 20/100, and 20/200, and participants in Experiment 2 experienced approximate acuities of 20/20, 20/50, and 20/300), participants attempted to determine the pedestrian interval (WALK, flashing DON’T WALK (FDW), or steady DON’T WALK (SDW)) and provide confidence ratings for each judgment. A critical comparison was conducted between two methods of signaling the pedestrian change (i.e., FDW) interval; 1.) simultaneous presentation of a countdown and flashing UPRAISED HAND, 2.) a countdown-only display without the flashing UPRAISED HAND. With the exception of performance in the 20/300 condition, participants’ accuracy on the interval discrimination task was overall rather high. However, under simulated visual impairments of 20/70 or worse, participants’ success at correctly determining the pedestrian interval was on average 21.5 percentage points lower when the countdown display was presented without the flashing UPRAISED HAND than when the countdown display was presented with the UPRAISED HAND. Participants’ average reported confidence in their judgments was also lower in the countdown-only condition, and their interval judgment response times showed a negative effect of the countdown-only display as well. Implications of the current findings with regards to visual impairment and signal displays for the pedestrian change interval are discussed.
  Authors: Scott, Alan C.; Swenson, Lindsay J.; Bentzen, Billie Louise; Barlow, Janet M.
  Authors: Scott, Alan C.; Swenson, Lindsay J.; Bentzen, Billie Louise; Barlow, Janet M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 429
  Paper Number: 13-1545
• Using Radio Frequency Identification to Improve Drivers' Awareness of Stop Sign at Unsignalized Intersections
  Abstract: Safety is always an important issue in stop sign controlled unsignalized intersections. Even though various engineering, education, and policy related strategies have been used, there are still a lot of lives and property lost at unsignalized intersections. In this paper, a Radio Frequency Identification (RFID) based Drivers Smart Assistance System (DSAS) was developed. The system hardware are all very cheap devices, while the current version of the system software is compiled in the computer program Visual Basic (VB). The RFID tags are placed on roadside, while the readers (receivers) and other devices such as GPS are equipped into the vehicles. Once a tag coded as a stop sign is detected by the in-vehicle reader, the warning signal(s) will be broadcasted to drivers in the form of verbal and/or image message. In order to understand the effects of this system, twenty subjects were recruited and tested while driving in a residential area in Houston. The statistical results from the tests show that the warning message from the DSAS can help vehicles to start to decelerate at an earlier distance to the unsignalized intersection, and thus would possibly enhance the safety at such intersections. Besides, the impacts of DSAS on vehicle emissions were also tested. Results show that the effects of DSAS on vehicle emissions are not very clear, which may need more tests in wider areas.
  Authors: Qiao, Fengxiang; Wang, Xiaobing; Yu, Lei; Jia, Jing
  Authors: Qiao, Fengxiang; Wang, Xiaobing; Yu, Lei; Jia, Jing
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-1585
• Impact Assessments of On-street Parking Guidance System on Mobility and Environment
  Abstract: Studies have revealed that a relatively large number of motorists travelling within central city areas spend a significant amount of their total trip time looking for on-street parking spaces. This search for parking spaces intensifies the overall amount of traffic congestion and worsens environmental quality. Recently, real-time parking information disseminated through parking guidance systems (PGSs) have been proposed to alleviate this congestion and improve the environment quality in urban centers. This study uses simulation to explore the effect of the deployment of a PGS on network mobility and vehicular greenhouse gas (GHG) emissions of vehicles traveling within a central business district area. Using a case study, several scenarios are developed to explore conditions and operational settings that the highest gains can be achieved from the PGS deployment. The findings demonstrate that PGSs have the potential to improve mobility and reduce vehicular emissions at any level of market saturation, whether or not near-real-time traffic data is integrated into the route guidance system. The most significant reductions in vehicular emissions and delays are realized under conditions where the demand for parking is greater than the availability of parking places; suggesting that as cities become more densely populated, PGSs will become more necessary to reduce congestion and improve urban air quality. The study also analyzes the impacts of simultaneous deployment of near-real-time traffic information system (ATIS) and PGSs, as demands increase. The findings suggest that the close integration and coordination of ATIS and PGSs is beneficial in order to decrease delays and improve mobility.
  Authors: Moini, Nadereh; Hill, David; Shabihkhani, Rooholamin; Homami, Hassan Rezaei
  Authors: Moini, Nadereh; Hill, David; Shabihkhani, Rooholamin; Homami, Hassan Rezaei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1615
• 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
• Test on Driving Behavior and Judgement of Appropriate Speed with Different Road Surfaces Conditions in Curve Sections
  Abstract: For safe driving, it is essential that the driver properly recognize road alignment, pavement markings and other traffic control devices. At the same time, road surface conditions vary with weather conditions. In snowy regions, the road surface during winter can be compacted-snow, dry or wet. Under the compacted-snow condition, drivers are not able to see the pavement markings, and on rural highways, control speed according to the linear curve is important for safe. In autumn 2011 and winter 2012, the authors conducted driving tests on driving behavior and selection speed under the dry and compacted-snow conditions in curve section of two-lane highway. Ten drivers participated in a test on a road section in service. An eyes measurement system with vehicle dynamics recorder was installed on a test vehicle that traveled both directions on a 10.5-km test section of two-lane highway in Eastern Hokkaido, Japan. Ten male drivers drove the test vehicle under free-flow condition. The test vehicle was traveling in various curves of test section. The driving behavior in the curve sections recorded using a vehicle dynamics recorder on the rear seat. It was found that the selection speed of driver in the curve section is lower for the compacted-snow condition than for the dry condition, and that the variation in lateral acceleration was lower for the compacted-snow condition than for the dry condition.
  Authors: Munehiro, Kazunori; Kageyama, Hiroyuki; Takahashi, Naoto; Ishida, Tateki; Asano, Motoki
  Authors: Munehiro, Kazunori; Kageyama, Hiroyuki; Takahashi, Naoto; Ishida, Tateki; Asano, Motoki
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 603
  Paper Number: 13-1633
• Impact of Education on Nonmotorist Gate Violations at Highway-Rail Grade Crossings
  Abstract: The objective of this research was to investigate the effectiveness of education in reducing non-motorists’ gate violations at a dual-quadrant gated highway-rail grade crossing (HRGC). The methodology consisted of observing gate violations by non-motorists at the chosen crossing for seven days before and seven days after a two-day educational activity. This educational activity involved on-site showing of Operation Lifesaver’s safety videos and distribution of educational materials amongst non-motorists. Two types of gate violations were monitored in this research: passing under descending gates (V1) and passing around fully lowered gates (V2). An important aspect of the study was keeping stock of opportunities for gate violations available to non-motorists besides counts of committed violations. A before-after comparison showed statistically significant reduction in V1 violations after the educational activity. However, a closer inspection revealed this reduction was due to fewer V1 opportunities available in the post education period rather than due to the undertaken educational activity. A detailed analysis of V2 violations showed a statistically significant reduction in the post education period after accounting for V2 violation opportunities and other factors. This reduction was attributed to the undertaken educational activity. The findings underscore the need to account for violation opportunities in before-after comparisons of HRGC gate violations to avoid incorrectly assigning credit for safety changes to measures undertaken in hopes of improving safety.
  Authors: Luo, Zheng; Khattak, Aemal
  Authors: Luo, Zheng; Khattak, Aemal
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 338
  Paper Number: 13-1681
• Characterizing Performance of Arterial Traffic Flow Using Probe Vehicle Data
  Abstract: There is extensive literature in the adaptive control field that uses local detection available from the traffic controller as inputs to various control models for adjusting splits, cycle length, and offsets. All of these models make some implicit control objective. Some of these objectives include facilitating progression, minimizing stops, minimizing delay, providing equitable allocation of green time, and including transit and pedestrian modes. There is an enormous opportunity to incorporate probe data into the decision process for where and when adaptive control could be used, what operating objectives are most applicable to the corridor, and as an outcome assessment tool for evaluating the effectiveness of adaptive control performance. This paper demonstrates how a variety of currently available probe data sources can statistically characterize and be used to identify appropriate adaptive control objective(s) and assess outcomes. Four case studies are discussed that use anonymous Bluetooth MAC address matching, crowd sourced probe data, and profiling of vehicles with wireless magnetometers to demonstrate how travel time data could potentially be used to evaluate existing conditions, how the outcome of a traditional signal retiming, and assessing the feasibility of adaptive control opportunities. Currently the richest probe data sets are provided by agency installed equipment. However, with the penetration of crowd sourced probe data devices and the onset of connected vehicle infrastructure, it is important to look forward to how those data sources could be enhanced or shaped to provide similarly rich data. This paper concludes by recommending that commercial data providers begin developing more detailed base maps that provide richer probe data information such as hour-by-hour statistical distributions approach delay for signalized arterials where the segments do not span multiple intersections. By quantitatively articulating the case for richer probe data sets, this will provide the motivation for agencies to develop more detailed specification for probe data that better serves their needs.
  Authors: Remias, Stephen Matthew; Hainen, Alexander Michael; Day, Christopher M.; Brennan, Thomas M.; Li, Howell; Rivera, Erick Manuel; Sturdevant, James R.; Young, Stanley E.; Bullock, Darcy M.
  Authors: Remias, Stephen Matthew; Hainen, Alexander Michael; Day, Christopher M.; Brennan, Thomas M.; Li, Howell; Rivera, Erick Manuel; Sturdevant, James R.; Young, Stanley E.; Bullock, Darcy M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-1812
• Multilevel Modeling of Commercial Vehicle Interarrival Duration Using GPS Data
  Abstract: Variation in truck travel patterns between days is difficult to measure due to a lack of multiple-day commercial travel surveys. This study uses truck GPS data to study inter-arrival duration, defined as the time between arrivals at a destination of two successive vehicles operated by the same carrier. Destinations were separated into market segments: 1) frequently-visited destinations, 2) regularly scheduled destinations, and 3) unscheduled destinations, based on visit frequency and regularity. Inter-arrival duration was modelled using multilevel ordered probit and multilevel multinomial logit models. Market segmentation improved modelling results, and multilevel models performed better than single level models.
  Authors: Sharman, Bryce; Roorda, Matthew J.
  Authors: Sharman, Bryce; Roorda, Matthew J.
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1816
• 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
• Overview of Bunker Consumption Optimization in Shipping
  Abstract: Bunker consumption optimization is significant for shipping companies because bunker cost constitutes a large proportional of the total operating cost and bunker consumption is directly related to emissions. Bunker consumption optimization problems can generally be formulated as the mixed-integer nonlinear programming models, which are challenging in algorithm design for solving large-scale problems. In this paper, we review the solution algorithms in the literature and propose a number of new algorithms. The algorithms that are reviewed and proposed include enumeration, dynamic programming, discretization, linear (and quadratic) static (and dynamic and branch-and-bound) outer-approximation (and secant-approximation) algorithms, and a second-order cone programming approach. The applicability, optimality, and efficiency of these methods are investigated.
  Authors: Wang, Shuaian; Meng, Qiang; Liu, Zhiyuan
  Authors: Wang, Shuaian; Meng, Qiang; Liu, Zhiyuan
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1859
• Risk-Based Vehicle Routing and Scheduling Problem with Time Windows in Hazardous Material Transportation
  Abstract: Unlike normal traffic incidents, incidents involving hazardous material are associated with significant traffic delays. As highways in cities are getting more and more crowded, monetary loss of the delay is getting massive. The formulation of the hazardous material routing and scheduling problem presented in this paper considers such potential effect of a hazardous material incident, in addition to the traditionally considered risk to exposed population. Loss due to congestion created by the incident is used as its measure. The objective is to minimize sum of the population-based and congestion-based risk cost. The model was used to explore routing and scheduling in a virtual instance of hazardous material transportation derived from road network of Osaka City, Japan. The problem was solved using Ant Colony System-based algorithms and was compared with optimal routes obtained considering population-based and congestion-based risk, respectively, as the sole criterion. The comparison showed that the model provides a better alternative to the conventional population-based model as it gives compromised optimal solution avoiding paths that causes large increase of the congestion-based cost.
  Authors: Pradhananga, Rojee; Taniguchi, Eiichi; Yamada, Tadashi; Qureshi, Ali Gul
  Authors: Pradhananga, Rojee; Taniguchi, Eiichi; Yamada, Tadashi; Qureshi, Ali Gul
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1865
• Fuzzy Logic for Improved Dilemma Zone Identification: A Driving Simulator Study
  Abstract: Type-II dilemma zones are the segment of roadway approaching an intersection where drivers have difficulty deciding to stop or proceed at the onset of the circular yellow (CY) indication. Signalized intersection safety is improved when dilemma zones are correctly identified and steps are taken to reduce the likelihood that vehicles are caught in such zones. This research purports that using driving simulators as a means to collect driver response data at the onset of the CY indication is a valid methodology to augment our analysis of decisions and reactions made within the dilemma zone. The data obtained was compared against that from previous experiments documented in the literature and the evidence suggests that driving simulator data is valid for describing driver behavior under the given conditions. Fuzzy logic was proposed as a tool to model driver behavior in the dilemma zone, and three such models were developed to describe driver behavior as it relates to the speed and position of the vehicle. These models were shown to be consistent with previous research on this subject and were able to predict driver behavior with up to 90% accuracy.
  Authors: Moore, Derek; Hurwitz, David S.
  Authors: Moore, Derek; Hurwitz, David S.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-1835
• Local Linear Model Tree Approach to Develop Car-Following Model Considering Lead Vehicle Types
  Abstract: Car-following models play a key role in the traffic microscopic simulations. They have a significant impact on accuracy of replicating real world traffic behaviour. Recent studies showed that drivers’ behaviour varies when the following vehicle is a passenger car or when it is a heavy vehicle. However, existing models do not accurately address these differences. This oversight could diversely affect the accuracy of traffic micro-simulations in particularly with the current trend of increasing number of heavy vehicles in the traffic stream. This paper aims to propose a new car-following model which considers the types of lead vehicles. Two types of lead vehicles were considered in this study (i.e. passenger cars and heavy vehicles). The model was developed based on the local linear model tree (LOLIMOT) approach which can be considered as an artificial intelligence model. This approach is able to incorporate human perceptual imperfections into a car-following model. It defines some localities in the input space and develops a specific model for each locality. Then it combines the models in a fuzzy manner to predict the final output. This paper used two different real world data sets obtained from a US freeway in congested traffic conditions for training and testing purposes. The results showed very close agreement between the real data and the outputs of the proposed model.
  Authors: Aghabayk, Kayvan; Sarvi, Majid; Forouzideh, Nefiseh; Young, William
  Authors: Aghabayk, Kayvan; Sarvi, Majid; Forouzideh, Nefiseh; Young, William
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1837
• Development of Degree-of-Priority Based Preemption Control Strategy for Emergency Vehicle Operation
  Abstract: This paper proposes a degree-of-priority based preemption control strategy for emergency vehicle operation to decrease the impacts of emergency vehicles on normal traffic. The proposed model features its effectiveness to following three aspects: (1) a multilayer fuzzy model was established to determine the degree-of-priority based on emergency vehicle preemption demand intensity and preemption control influence intensity; (2) for emergency vehicles with proper classification, a travel time estimation model for emergency traffic was formulated, and an optimal emergency route determine model based on the level of priority of emergency events and the emergency vehicle travel time was developed to minimize evacuation time as well as minimize the adverse impacts of preemption on normal traffic; and (3) a conditional traffic signals priority control method at each intersection of the evacuation route was built, so that traffic queue at each intersection can be cleared previous the arrival of emergency vehicles. A simulation model based on field data was developed, and the performance of the proposed strategy was compared with the conventional local-detection based method under the microscopic simulation model. The results validated the efficiency of the proposed strategy in terms of minimizing the delay of emergency vehicles and reducing adverse impacts on normal traffic.
  Authors: Wang, Jiawen; Yang, Xiaoguang; Ma, Wanjing
  Authors: Wang, Jiawen; Yang, Xiaoguang; Ma, Wanjing
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-1891
• Modeling Temperature Distribution in Soil Profile: Impacts of Moisture Transport, Snow Cover, and Soil Freezing
  Abstract: Prediction of soil temperature is important to simulation of pavement, railway and bridge with significant earth contact. A one-dimensional numerical model for heat and moisture transfer in partially frozen soils has been developed and validated. In addition to modeling conduction heat transfer, model variations that include moisture transport, snow accumulation and melting and soil freezing and thawing are investigated. This model was evaluated against measured data at depths of 0.5 and 1.0 m for two locations in the northern United States of America. The results show that the model is capable of providing good simulations of the evolution of temperature all over the year. Comparisons of simulation results with five combinations of modeled phenomena to experimental data demonstrate that both snow cover and freezing and thawing of soil are of important when modeling temperature for soil. However, temperature was not substantially affected by the moisture transport.
  Authors: Xu, Hui-ning; Yiqiu, Tan
  Authors: Xu, Hui-ning; Yiqiu, Tan
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 375
  Paper Number: 13-1924
• Bilevel Model for Optimal Shelter Selection in Emergency Evacuation Operations
  Abstract: Due to the frequent happening of catastrophic natural disasters and man-made disasters in recent decades, emergency management has become an important issue around the world. Therefore, effective traffic operations for emergency evacuation during emergency events are critical to alleviate the impact from disasters. Designing well-planned evacuation routes is the first priority for the evacuation process. Before planning the evacuation routes, the evacuation demand patterns for different areas in different disaster scenarios must be known. Moreover, the shelter locations are the basis for us to plan for evacuation routes. This research proposes a bi-level programming model to combine the shelter location problem and the evacuation trip distribution problem. The shelter location problem is formulated as a mathematical model solved by the CPLEX optimizer in the upper level. The evacuation trip distribution problem is solved by an entropy-based gravity model and the DynaTAIWAN simulation assignment model in the lower level. The upper level aims to determine the location of shelters selected, while the lower level aims to determine the trip distribution from the result of shelter location problem. The results from the proposed model determine the locations of shelter and the total number of shelters. This research suggests the Kaohsiung City Government should setup “regular shelter” and prepare emergency kits (survival kits) and emergency relief (goods or materials in emergency) at the regular shelters for the sake of emergency conditions.
  Authors: Hu, Ta-Yin; Ou, Hui-Ching; Ho, Wei-Ming
  Authors: Hu, Ta-Yin; Ou, Hui-Ching; Ho, Wei-Ming
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-1929
• Parking Fare Planning Approach for Special Events Based on Bilevel Programming
  Abstract: During special events, intensive short-term travel leads to serious shortage of parking. Remote parking lots have been planned and preferential policies are implemented to encourage the Parking/Riding (PR) travel for special events. However, how to plan a suitable parking fare strategy and balance trip flow between parking lots is a challenge. In this paper, special events parking fare optimization model is proposed based on the bi-level programming model framework. Parking/Riding and Parking/Walking mode travel mode for private mobile is analyzed. Logit-based utility model, which considering driving time, parking fare, bus fare, travel expenses and other major factors, describes the behavior of travelers¡¯ parking choose; it is an equilibrium traffic assignment problem and considered as the lower model of bi-level programming. The upper level model which established by considering system total travel time, parking fares and parking capacity constraints, describes traffic managers¡¯ consideration. The solutions of the bi-level programming model are based on Discrete Particle Swarm Optimization (DPSO) and Convex Combinations Method (CCM) algorithms. Numerical experimental results indicate that an optimal parking fare plan is able to control parking demands and re-distribute parking flow between different parking lots to release congestion.
  Authors: Nengchao, LV; Yan, Xinping; Wu, Chaozhong; Zhong, Ming; MAO, Shuhua
  Authors: Nengchao, LV; Yan, Xinping; Wu, Chaozhong; Zhong, Ming; MAO, Shuhua
  Year: 2013
  Document Type: Paper
  Subject: Finance; Operations and Traffic Management; Policy
  Session: 294
  Paper Number: 13-1901
• Car-Following Behavior at Sags and Its Impacts on Traffic Flow
  Abstract: Sags are freeway sections along which gradient changes significantly from downwards to upwards. Sags often become bottlenecks in freeways. With high traffic demand, congestion generally forms on the fast lane(s) of the uphill section and then it spreads to the slow lane(s). Previous studies suggest that the capacity of the fast lane(s) decreases on the uphill section due to changes in car-following behavior and an increase in the frequency of lane changes. However, it is not clear which of those two factors is dominant. The aim of this paper is to identify the primary factor triggering the formation of congestion at sags. To this end, we analyze vehicle trajectories collected by means of video cameras on a sag in Japan. First, we analyze the relation between average time headway and speed on the fast lanes at different locations. The results indicate that, at similar speeds, drivers tend to keep longer headways on the uphill section than on the downhill section. Therefore, lane capacity decreases on the uphill section. Second, we identify the causes of formation and growth of traffic flow disturbances on the fast lanes. The results show that in almost all cases the formation and growth of disturbances is triggered by car-following instabilities; disruptive lane changes are a less frequent triggering factor. We conclude that the capacity of the fast lanes decreases at sags primarily as a result of the changes in car-following behavior that occur on the uphill section.
  Authors: Goni Ros, Bernat; Knoop, Victor L.; van Arem, Bart; Hoogendoorn, Serge
  Authors: Goni Ros, Bernat; Knoop, Victor L.; van Arem, Bart; Hoogendoorn, Serge
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1907
• METEOSAFETY: Multiagent System to Support Automated Activation of Traffic Management Plans for Adverse Weather Situations
  Abstract: The dynamism of traffic flows implies the research and new technologies development within traffic management and control strategies to achieve the improvement of traffic flows and road safety. Artificial intelligence could support traffic entities and road operators to manage possible incidents on the road network, especially when the incidents are related to adverse weather conditions. In this case, the probability of road accidents is increased due to the difficulty of driving under bad weather conditions. Thus, when an incident occurs road operators must decide how to cope with it in order to improve traffic safety. In Meteosafety project, a new MultiAgent System (MAS) to support traffic management has been developed. MAS technology helps to deal with the specific characteristics of traffic domain. The proposed MAS is able to work in two ways: a) coordinately, where all the agents work to solve weather problems in large networks and b) locally, where if communications breakdown, a small groups of agents work together to inform road users about weather problems. MAS is based on a rule-based system. This system is able to produce meteorological alarms with a high level of quality by applying specific coherence and correlation rules. So, it improves the road operator confidence in the decisions taken by the expert system. Furthermore it supports road operators proposing the best actions to take when any adverse weather situations with influence in the traffic flow happens.
  Authors: Tomás-López, Vicente R.; Martínez, Juan José; Soriano, Francisco R.; Martínez, Javier
  Authors: Tomás-López, Vicente R.; Martínez, Juan José; Soriano, Francisco R.; Martínez, Javier
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 603
  Paper Number: 13-1980
• Transportation System Performance Under Inclement Winter Weather: Perspectives from Weather-Induced Multiple Hazard Situations and Traveler Information
  Abstract: This study investigated the impacts of weather-induced multiple hazard situations, such as a snow storm accompanies by a major car accident on a highway, on road network performance in urban areas. A dynamic traffic assignment model was built for the study area in Amherst, New York, using the mesoscopic dynamic traffic assignment simulation package DynusT. Various hazard scenarios were simulated, including single events such as a snow storm or a car accident only scenarios and the combination of them. Both network-wide analyses and link-based analyses were conducted to examine the impact of hazard situations on travel time. In addition, different traveler information mitigation strategies were also evaluated based on the weather-induced multiple hazard situation. The results indicate that weather-induced multiple hazard situation affects network performance more significantly than single events. As traveler information dissemination strategies are concerned, both the variable message signs (VMS) and the en-route guidance are effective in mitigating hazard impact. En-route guidance performs better from the system perspective and brings more travel time savings. In comparison, VMS are more beneficial to the vehicles that are subject to both inclement weather and weather-induced incidents. Based on the findings, practical implications were produced to help traffic operation agencies to select appropriate traveler information dissemination strategies and determine the best information coverage rate.
  Authors: Hu, Jinge; Wang, Qian; Sadek, Adel W.; Wang, Zhiyong
  Authors: Hu, Jinge; Wang, Qian; Sadek, Adel W.; Wang, Zhiyong
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 603
  Paper Number: 13-2000
• Dynamic Feedback-Control Toll Pricing Methodology for Revenue Maximization: Case Study on I-95 Managed Lanes
  Abstract: Recently, congestion pricing emerged as a cost-effective and efficient strategy to mitigate the congestion problem on freeways. This study develops a dynamic toll strategy based on feedback control rules and compares its performance to that of the current strategy deployed on Interstate 95 express lanes. The proposed strategy aims to maximize the toll revenue while maintaining a minimum desired level of service on the managed lanes. The performance was examined for low and high traffic demand. A detailed numerical example is provided to explain how the proposed strategy works, and an external module is developed to execute the strategy in real time during VISSIM runtime. The impact of the value of time and level of income is also examined. Three values ranging from 60% to 120% of the mean hourly income are used. The results show that for high demand, an increase in the probability of choosing managed lanes is obvious, with the highest increase observed for the case of 120%. Also, during high demand, high income groups exhibit higher probabilities of choosing the managed lanes as a result of the increase in travel time savings and despite the increase in toll rate. When compared to the currently adopted toll pricing strategy on I-95, the proposed strategy shows a steadier toll rate profile, while keeping the speed at 45 mph or more and producing larger toll revenue.
  Authors: Cheng, Danhong; Ishak, Sherif
  Authors: Cheng, Danhong; Ishak, Sherif
  Year: 2013
  Document Type: Paper
  Subject: Finance; Operations and Traffic Management; Policy
  Session: 294
  Paper Number: 13-2045
• Developing Cost Estimation Models for Road Rehabilitation and Reconstruction
  Abstract: The average unit costs of road works vary substantially between countries, and even between projects in the same country, due to a number of factors. In this paper an effort is made to develop prediction models for the unit costs of road works that could be applied for a wide range of conditions in different countries.A specialized dataset was used, which was generated under a World Bank study that included road works contracts from 14 countries in Europe and Central Asia (ECA). Two techniques were used for model development: multiple regression analysis and artificial neural networks. As the major problem found with the data set was missing or incomplete data, classification trees were used as an intermediate step to evaluate the correctness of the selected parameters.Three models were developed using regression analysis, two for the unit cost of asphalt concrete and one for the cost per km of rehabilitation and reconstruction works. The models include as independent variables the price of diesel fuel, country Gross National Income, World Governance Index, Transparency International Corruption Perception Index, percent of local bidders participating in the tender, and climate conditions. The analysis using classification trees confirmed the appropriateness of the variables selected in the regression analysis. The models developed using artificial neural networks were superior compared to the regression models, using mostly the same parameters.The resulting models could be particularly useful at the strategic level, for planning and optimization of works on road networks in ECA countries.
  Authors: Cirilovic, Jelena; Vajdic, Nevena; Mladenovic, Goran; Queiroz, Cesar
  Authors: Cirilovic, Jelena; Vajdic, Nevena; Mladenovic, Goran; Queiroz, Cesar
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-2037
• Modeling Large-Truck Safety Using Logistic Regression Models
  Abstract: Statistics shows that crashes involving large trucks are generally more severe than those involving other vehicles due to the size, weight, and speed differential between trucks and other vehicles. Given the critical position of trucking in the process of economic recovery and growth, it is urgent to improve truck safety and mitigate any negative impacts to non-truck vehicles. Statistical models have been used universally to identify the contributing factors to crash severities and estimate injury probabilities. These different methodologies, albeit addressing different issues, may provide mixed results and the estimate accuracy may vary.The primary objective of this research is to investigate the effects of key determents to crash severities involving large trucks and to explore the relationship between them. The secondary objective is to provide insight on statistical applications by evaluating three logistic regression models: multinomial logistic (MNL), partial proportional odds (PPO), and mixed logistic (ML) models. The model results show that the majority of the coefficient estimates are consistent across the models studied. A few exceptions include young drivers and the use of safety constraints, which are not statistically significant in the ML model. The goodness-of-fit and model predictive power indicates that the PPO model produced the results that more closely resembled observations.
  Authors: Qin, Xiao; Wang, Kai; Cutler, Chase E.
  Authors: Qin, Xiao; Wang, Kai; Cutler, Chase E.
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-2067
• Improving Transportation Resource Coordination for Multimodal Evacuation Planning: Literature Review and Research Agenda
  Abstract: In a large-scale urban evacuation necessitated by a disaster, many can self-evacuate in private automobiles, but evacuating “carless” individuals and families poses a great logistical challenge that many cities, counties, and states cannot meet. A majority of emergency operations plans for large urbanized areas are insufficient in describing in specific and measurable terms how a major evacuation could be conducted successfully. This study first systematically reviews the challenge of multi-modal evacuation planning and next presents a detailed literature review of published research and government documents to identify barriers to improving multi-modal evacuation planning using high-capacity vehicles to transport those who cannot self-evacuate. Findings suggest that, despite a body of research on multi-modal transportation and the importance of integrating it into evacuation planning, most state and local governments do not have adequate planning processes, training, and exercises to evacuate households without automobiles. A research agenda about multi-modal evacuation planning is outlined, and a new volunteer-driven community-supported evacuation organization is suggested.
  Authors: Hess, Daniel Baldwin; Conley, Brian W.; Farrell, Christina M.
  Authors: Hess, Daniel Baldwin; Conley, Brian W.; Farrell, Christina M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 514
  Paper Number: 13-2084
• Investigation of Early-Onset Breakdown Phenomenon at Urban Expressway Bottlenecks in Shanghai, China
  Abstract: Based on the analyses of recurring bottlenecks in Shanghai¡¯s expressways using spatial-temporal diagram, three typical isolated bottlenecks (a lane drop, an on-ramp, and a weaving section) were selected and method of transformed curves was adopted to investigate the traffic flow characteristic using the loop detector data. The starting and ending times of the three kinds of bottlenecks, pre-queue flow (PQF), queue discharge flow (QDF) were analyzed. Finally, some conclusions were discovered that QDF was higher than PQF in bottleneck sections of lane drop and on-ramp, the average difference were 18% and 27% respectively, but the situation was different in weaving section, the average rate of reduction was 22%. The findings were obviously different from results of diverse bottlenecks in other countries (e.g. M4 motorway near London, United Kingdom, I-494 in Minneapolis, Minnesota, USA, the Queen Elizabeth Way (QEW) and the Gardiner Expressway in metropolitan Toronto, Canada), i.e., the bottlenecks in lane drop section and on-ramp bottleneck have the early-onset characteristics. At last, the reasons of early-onset breakdown were preliminarily discussed from the aspects of driving behaviors, the temporal feature of flow rate and the feature of merging.
  Authors: Sun, Jian; Zhang, Juan; Zhang, H. Michael
  Authors: Sun, Jian; Zhang, Juan; Zhang, H. Michael
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2105
• Forecasting Freeway Dynamic Travel Times by Constructing Trip Trajectories
  Abstract: The paper develops a novel approach to construct vehicle trajectories using real-time and historical traffic data to predict dynamic travel times. The approach combines real-time and historical data within a particle filter framework to dynamically predict future traffic state maps. The predicted travel trajectory is then constructed using the velocity spatiotemporal map. Based on the nature of particle filters, the variance of each speed grid traversed during the trip can be calculated and then used to compute the travel time variance. The proposed approach is tested using simulated data along a section of I-66. The prediction results demonstrate that the proposed method produces a prediction error half that of the other state-of-the-art methods with a mean absolute deviation of 1.30 minutes and a mean absolute percentage error of 6%.
  Authors: Chen, Hao; Rakha, Hesham
  Authors: Chen, Hao; Rakha, Hesham
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-2128
• Developing Long-Range Vision and Strategic Plan for the Future of the Manual on Uniform Traffic Control Devices
  Abstract: The MUTCD serves as the national standard for all traffic control devices used on roads and bicycle trails open to public travel. The MUTCD was first published in 1935 and has been updated on a regular basis since then with the 2009 edition being the tenth and most recent. Throughout its life, changes to the MUTCD have tended to occur on an incremental basis with little overall strategic direction behind a specific edition. The 2009 MUTCD represents several changes in the philosophical approach to traffic control device standards. As a result of those changes and in an effort to provide some strategic direction for future changes, the National Committee on Uniform Traffic Control Devices established a task force to develop a long-range vision and strategic plan for the MUTCD. After a period of internal progress on the effort, the National Cooperative Highway Research Program established a research project so that the strategic planning process could be expanded and incorporate input from a larger variety of MUTCD stakeholders. This paper describes the current status of the strategic planning process and summarizes some of the key issues that are at the heart of developing a long-range vision. Examples of these issues include: what is the purpose of the MUTCD, who is the target user that the MUTCD is prepared for, what level of detail is appropriate for the MUTCD, how should the MUTCD be organized, who is the group of road users that traffic control devices are intended to address, what is the appropriate number of changes for an MUTCD revision, and what are the communication options for presenting MUTCD content. It is hoped that this paper can be presented at the TRB Annual Meeting in order to introduce the planning effort to the largest possible audience and thereby improve the number and quality of comments received from MUTCD stakeholders.
  Authors: Hawkins, H. Gene
  Authors: Hawkins, H. Gene
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 429
  Paper Number: 13-2117
• Hybrid Work Zone Information System Based on Dedicated Short-Range Communication with Portable Changeable Message Signs
  Abstract: The future deployment of dedicated short range communication (DSRC) technology requires that DSRC based applications are integrated with existing traffic management techniques so that non-DSRC equipped vehicles at the early stage of DSRC deployment can also reap the potential benefits of DSRC technology. We have successfully developed a hybrid traffic information system combining DSRC technology and portable changeable message signs (PCMS) for work zone environment to improve traffic mobility, and thereby, driver safety. The developed system uses DSRC based V2I and V2V communication to acquire travel safety parameters such as travel time (TT) and starting location of congestion (SLoC), and disseminate these parameters to both DSRC equipped vehicles and DSRC equipped PCMSs which are strategically placed alongside the road. Using the DSRC-PCMS interface developed and demonstrated in this work, PCMSs can receive these travel safety parameters from nearby DSRC equipped vehicles on the road via DSRC based V2V communication, and display them for the drivers of the vehicles lacking DSRC capability. Such a system can be useful for an early stage of DSRC deployment when the DSRC market penetration is low.Additionally, a rigorous analysis has been conducted to investigate the minimum DSRC market penetration rate needed for successful functionality of the developed system with respect to both acquisition and dissemination of TT and SLoC. Using realistic traffic flow model, guidelines are developed to estimate a minimum DSRC penetration rate needed to deploy the developed system for a variety of traffic scenarios on a given work zone road.
  Authors: Ibrahim, Umair; Hayee, M. I.; Kwon, Eil
  Authors: Ibrahim, Umair; Hayee, M. I.; Kwon, Eil
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-2137
• Impact of Lowered Residential Speed Limits in City of Edmonton, Canada
  Abstract: In 2010, the City of Edmonton reduced the posted speed limit (PSL) in six residential communities from 50 to 40 km/h. This study investigates the impact of the reduced limit on vehicle speeds using a before-after experimental design with control group adjustment.Continuous speed and traffic flow data were collected at 65 locations for a period of months including 1 month as a baseline before period and months representing the after period. Speed evaluation was performed at several levels ranging from individual speed survey locations to an over all aggregate analysis. Several performance indicators such as mean free-flow speed, speed variance, level of compliance, mean speed of speeders (drivers exceeding the PSL), and percentile speed profile were considered. The results revealed a statistically significant reduction in mean free-flow speed and speed variances for all combinations of time of day and day of week classifications. Though the compliance to the PSL was low after the limit reduction, compliance to a 15 km/h threshold above the PSL was significantly high. Moreover, the analysis showed that the effectiveness of the reduced PSL improved with the time.
  Authors: Islam, Md. Tazul; El-Basyouny, Karim; Ibrahim, Shewkar
  Authors: Islam, Md. Tazul; El-Basyouny, Karim; Ibrahim, Shewkar
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-2157
• Bluetooth Vehicle Reidentification for Analysis of Work Zone Diversion
  Abstract: Bluetooth vehicle re-identification technology has potential to improve understanding of driver route choice behavior associated with work zones. The Wisconsin Department of Transportation and the Smart Work Zone Deployment Initiative commissioned work zone diversion studies at four sites: two urban and two rural. Several Bluetooth detectors were deployed in pairs, triples and quadruples to help identify differences in route choice with and without lane closures. In spite of relatively low (and variable) detection rates, comparisons of the number of vehicles using specific routes during closure and non-closure periods revealed differences in driver behavior in urban vs. rural work zones. These techniques provide field data that can supplement conventional methods for estimating work zone diversion. The accuracy of the method can be expected to increase as the number of vehicles with onboard Bluetooth devices rises and Bluetooth detection technology continues to improve.
  Authors: Effinger, Justin; Horowitz, Alan J.; Liu, Yue; Shaw, John
  Authors: Effinger, Justin; Horowitz, Alan J.; Liu, Yue; Shaw, John
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 400
  Paper Number: 13-2159
• Green Rating Integration Platform: Decision-Making Tool for Multimodal Facilities: Sustainable Water and Material Practices
  Abstract: To achieve sustainability goals and receive credit points for green certification, it is essential to understand the strategies to accomplish the sustainability objectives of a project. Sustainability rating systems come with project goals and strategies. However, among the multitude of sustainability rating systems and guidelines, it is difficult to decide which goals will earn more credit points and what methods need to be followed to achieve particular goals. In addition, multi-modal projects have different focal areas and associated rating systems related to each mode or other aspect of the project. Five green ratings systems representative of these aspects have been selected and analyzed through an analytical hierarchy process (AHP). Previous research resulted in synchronization of the rating system topical categories and synthesis of the credits. This work focused on the water and material aspects, and the associated detailed goals and green methodologies. Key intents from the project goals and key strategies from the methodologies were identified. The lists of key intents and key strategies across the rating systems were then harmonized using an AHP and further cross-coded in an open database with the credit subcategories and corresponding rating systems. The database can filter the credit subcategories across the rating system for a specific key intent or key strategy. The harmonized lists and database will facilitate decision makers and sustainability practitioners in evaluating intents and methodologies for a project across multiple rating systems and thus, aid in achieving the desired levels of sustainability for multi-modal facilities.
  Authors: Haselbach, Liv; Alam, Ashraful; DeRooy, Garrett; Poor, Cara; Wolcott, Michael P
  Authors: Haselbach, Liv; Alam, Ashraful; DeRooy, Garrett; Poor, Cara; Wolcott, Michael P
  Year: 2013
  Document Type: Paper
  Subject: Construction; Environment; Operations and Traffic Management
  Session: 274
  Paper Number: 13-2175
• Evaluation of Temporary Ramp Metering for Work Zones
  Abstract: Ramp metering has been successfully implemented in many states to improve traffic operations on freeways. Studies have documented the positive mobility and safety benefits of ramp metering. However, there have been no studies on the use of ramp metering for work zones. This paper reports the results from the first deployment of temporary ramp meters in work zones in the United States. Temporary ramp meters were deployed at seven work zones in Missouri. Safety measures such as driver compliance, merging behavior, speed differentials, lane changing, and braking maneuvers were extracted from video-based field data. Mobility analysis was conducted using a calibrated simulation model and the total delays were obtained for under capacity, at capacity, and over capacity conditions. This evaluation suggests that temporary ramp meters should only be deployed at work zone locations where there is potential for congestion and turned on only during periods of high congestion. The compliance analysis showed that non-compliance could be a major safety issue in the deployment of temporary ramp meters. The use of a three-section instead of a traditional two-section signal head used for ramp metering produced significantly higher compliance rates. Mobility analysis revealed that ramp metering produces delay savings for high traffic volume work zones. For flows below capacity, ramp metering is not recommended since it increases total delays.
  Authors: Sun, Carlos; Edara, Praveen; Zhu, Zhongyuan
  Authors: Sun, Carlos; Edara, Praveen; Zhu, Zhongyuan
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-2193
• Next-Generation Intersection Control Algorithm for Autonomous Vehicles
  Abstract: This paper presents a reservation-based autonomous intersection control algorithm, named Autonomous Control of Urban TrAffic (ACUTA). The ACUTA allows centralized management of autonomous vehicles within a certain distance from the intersection to manage vehicles to pass the intersection with no conflict and few stops. To address some operational issues identified in previous studies on reservation-based autonomous intersection management, three operational improvement strategies are introduced and incorporated in the ACUTA. These strategies have been evaluated and proved to be effective under certain conditions. Along with the operational improvements of the ACUTA, its implementation in VISSIM is significant to achieve standardized evaluation of operational and safety performance using a widely applied simulation platform. This has never been accomplished in previous studies. Additionally, VISSIM simulations are established to compare the operational performances between a multi-tile ACUTA intersection and a signalized intersection and between a single-tile ACUTA intersection and a four-way stop intersection. Results obtained from both comparisons suggest that the ACUTA is more effective in maintaining a much lower intersection delay as well as a shorter or even empty queue. Sensitivity analyses are conducted on four configurable parameters of the ACUTA for a better understanding of how optimization can be done in the future. Granularity (number of tiles) is found critical in maintaining low intersection delays. Three other parameters are also found to have considerable impacts on the operational performance.
  Authors: Li, Zhixia; Chitturi, Madhav V.; Zheng, Dongxi; Bill, Andrea R.; Noyce, David A.
  Authors: Li, Zhixia; Chitturi, Madhav V.; Zheng, Dongxi; Bill, Andrea R.; Noyce, David A.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 674
  Paper Number: 13-2185
• 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
• Safety Implications of Truck and Car Speed Limits for Two-Lane Highway Operations
  Abstract: The safety implications of car-truck speed limits have not been adequately researched, and this has been especially true for two-lane highways. On two-lane highways speed controls can have a significant effect on rear-end and head-on vehicle interactions. This paper uses simulation to assess the effect on safety of different speed control strategies applied to two-lane highway operations. Two different types of speed control strategies are considered: uniform speed limit (USL) and car-truck differential, which is introduced in two different ways: discretionary differential car and truck posted speed limits (DSL) and mandated truck speed limiters (MSL). Safety implications are considered using three overtaking-related indicators: Number of vehicles overtaking (NOT), 2) Percentage time spent in “desire to overtake mode” (PTDO), and 3) Average Time-to-Collision (TTC) with the on-coming vehicle prior to returning back to the original lane. Vehicle interactions affecting safety are estimated through the application of a calibrated microscopic traffic simulation model to a 6Km straight segment of two-lane highway with zero and -3% grade.Differential speed strategies (DSL and MSL) were observed to have a slight increase in the total number and rate of overtaking maneuver in comparison to the uniform control strategy (USL). DSL strategies significantly increased the number and rate of car-truck overtakes over the range of volumes considered in the simulation, suggesting a negative effect on safety. At the same time the number of car-car overtakes were reduced suggesting a positive effect on safety. No considerable effects were observed concerning differential speed control strategies and average TTC and PTDO for the studied cases. The number of overtakes were found to be higher on the level segment than the downgrade segment for the control strategy; although, not very significant for MSL. Car-Car and Car-Truck overtakes appeared to be consistently higher in level section than the grade section; however, this was opposite where the MSL strategy was considered.
  Authors: Ghods, Amir H.; Saccomanno, Frank
  Authors: Ghods, Amir H.; Saccomanno, Frank
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 438
  Paper Number: 13-2329
• Emissions Evaluation of Intervehicle Safety Warning Information Systems for Moving Hazards Under Connected-Vehicle Environments
  Abstract: Driver inattentiveness is one of critical factors contributing to vehicle crashes. The inter-vehicle safety warning information system (ISWS) is a technology to enhance driver attentiveness by providing warning messages about upcoming hazards using connected vehicle environments. A novel feature of the proposed ISWS is its ability to detect hazardous driving events, such as abrupt accelerations and lane changes, which are defined as moving hazards with a higher potential of causing crashes. This study evaluated the effectiveness of the ISWS in reducing vehicle emissions and its potential for traffic congestion mitigation. Reliable estimation of the ISWS¡¯s effectiveness is valuable for improving the system¡¯s functionality and for developing new technologies, in addition to establishing and applying relevant policies that will disseminate ISWS technology for safety enhancement. This study included a field experiment that documented actual vehicle maneuvering patterns for abrupt accelerations and lane changes, which were used for more realistic simulation evaluations, in addition to normal accelerations and lane changes. Probe vehicles equipped with customized on-board units consisting of a global positioning system (GPS) device, accelerometer, and gyro sensor were used to obtain the vehicle maneuvering data. A microscopic simulator, VISSIM, was used to simulate a driver¡¯s responsive behavior when warning messages were delivered. A motor vehicle emission simulator (MOVES) was then used to estimate vehicle emissions. The results show that reduction in vehicle emissions increased when the ISWS¡¯s market penetration rate (MPR) and the congestion level of the traffic conditions increased. The maximum CO and CO2 emission reductions achieved were 5.81% and 6.69%, respectively, under LOS D traffic conditions. The outcomes of this study can be valuable for deriving smarter operational strategies for ISWS to account for environmental impacts.
  Authors: Jeong, Eunbi; Oh, Cheol; Lee, Gunwoo
  Authors: Jeong, Eunbi; Oh, Cheol; Lee, Gunwoo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 674
  Paper Number: 13-2334
• Calibration and Validation of a Regional-Level Traffic Model for Hurricane Evacuation
  Abstract: One of the key issues with evacuation models, or any traffic model, is that some public officials place little faith in the results generated by these models. The way to reassure doubts is by thorough calibration and validation of the model. However, there has been little research in this particular area of evacuation modeling. In an effort to expand the literature on evacuation model calibration/validation, the purpose of this paper is to provide a narrative in which the authors discuss the calibrated and validated a regional-scale evacuation model using observed evacuation data. A traffic simulation model was developed to analyze traffic conditions associated with a regional-level mass emergency evacuation for Southeastern Louisiana. The model was constructed using the TRANSIMS transportation modeling system. The narrative details three important aspects of traffic modeling: trip assignment convergence, macro-level calibration, and network flow validation. Similar results were found after testing two convergence criteria sets. A “descending” criteria set was ultimately chosen since it could lead to a more robust routing solution. During the calibration procedure, it was difficult to determine which parameter value would be the most appropriate. This was an expected result since the calibration focused on the entire regional network rather than select routes. The validation procedure revealed the importance of including background traffic in the simulation model. The results here should lead to further enhancements made toward effectively calibrating and validating traffic models for evacuation analysis.
  Authors: Montz, Thomas; Zhang, Zhao
  Authors: Montz, Thomas; Zhang, Zhao
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-2339
• Modeling and Analysis of Car-Truck Heterogeneous Traffic Flow Based on Intelligent Driver Car-Following Model
  Abstract: The traffic flow heterogeneity caused by the different car-following dynamics among the different types of vehicles has drawn increasing attention recently. This paper explores the characteristics of the four types of car-truck car-following combinations, car-following-car (CC), car-following-truck (CT), truck-following-car (TC) and truck-following-truck (TT), and their impact on traffic flow stability. A heterogeneous traffic flow model based on the Intelligent Driver car-following model (IDM) is proposed and calibrated using the Next Generation Simulation (NGSIM) vehicle trajectory data. Based on the calibrated model, the characteristics of the car-truck heterogeneous traffic flow are evaluated using the linear stability analysis, fundamental diagrams, and shock wave characteristics. The linear stability analysis identifies two critical factors that can influence the stability of the car-truck heterogeneous traffic flow: the stability functions and the proportions of the four types of car-truck combination. Cars and trucks can both stabilize and destabilize the traffic flow depending on the combination type and the equilibrium velocity. Fundamental diagrams of car-truck heterogeneous flow are found to be determined by the distance headways and proportions of the four types of combination. Moreover, the fundamental diagrams of different car-truck combinations converge to several clusters with the same proportion difference between the CC and TT combinations. The slowing-down effect of trucks on shock wave speed in the car-truck heterogeneous traffic flow is also observed in the simulation.
  Authors: Yang, Da; Jin, Jing; Ran, Bin; Pu, Yun; Yang, Fei
  Authors: Yang, Da; Jin, Jing; Ran, Bin; Pu, Yun; Yang, Fei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2358
• Empirical Identification and Quantification of Driver Anticipation Factor in Car-Following Behavior Modeling
  Abstract: In car-following behavior modeling, the anticipation factor represents the situation that drivers change the speed based on their predicted traffic condition, rather than the current condition. While current models address the anticipation factor as a constant, it is actually a dynamic variable in reality. This paper presents a new car-following model that incorporates the anticipation factor as a variable. The data from a field experiment reveal that the anticipation factor is a function of the drivers’ choice of braking process and the application of the advanced driving assistance system. The observed anticipation factor values are compared with the theoretical boundary, which is obtained from a linear stability analysis for the new car-following model. The comparison results show that the observed values are in the stable region, which indicates the modeling effort is consistent with the field observation. The new car-following model, in conjunction with the observed anticipation factor, is utilized in several simulation experiments in order to identify the influence of the anticipation factor on traffic flow. It is found that when the anticipation factor takes into effect on more drivers, it is easier for the traffic flow to recover to stability from local disturbances. The new car-following model is helpful for microscopic traffic simulation models and applications of Intelligent Transportation System (ITS).
  Authors: Liu, Hao; Wei, Heng; Yao, Zhuo; Ai, Qingyi
  Authors: Liu, Hao; Wei, Heng; Yao, Zhuo; Ai, Qingyi
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 546
  Paper Number: 13-2360
• On Observable Chaotic Maps for Queuing Analysis
  Abstract: A queueing model based on chaotic mapping offers a number of distinct advantages over both stochastic and static deterministic models. Depending on the type of chaotic map used, such a queue can capture transient behavior, intermittency, steady state behavior, and complex distributions in arrival rates. These characteristics are especially desirable in many queueing applications in transportation. Earlier studies resulted in chaotic queueing models that cannot be estimated using observed arrivals. An alternative queueing model is presented along with methods to specify the model, interpret its results, and estimate its parameters. The proposed queueing model uses chaotic maps of inter-arrival times to generate arrivals so that parameters can be calibrated with observable data. A sample queue based on the ergodic logistic map is presented. To calibrate the mapping based on observed data, a joint parameter and state estimation algorithm is presented using the method of successive averages. An illustration is made with two connected queues to show how a purely deterministic queueing network can still result in a joint invariant distribution. The results offer a positive view of this method and its applicability to queueing problems, particularly in the field of transportation and dynamic network loading.
  Authors: Chow, Joseph Y. J.
  Authors: Chow, Joseph Y. J.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2366
• Evaluation Framework for High-Occupancy-Toll Lanes
  Abstract: A high-occupancy/toll (HOT) lane is an increasingly popular form of traffic management which reserves a set of freeway lanes for HOVs and transit users, while allowing low-occupancy vehicles (LOV) to enter for a fee. In turn HOT lanes must maintain a minimal level of service which is accomplished by regulating the volume of entering LOVs. Modeling the choice process which dictates the volume of LOVs that choose to pay and take the HOT lane is integral in the toll setting process, and the focus of this paper. Two simple formulations (an all-or-nothing assignment and an additive logit model) are compared with a formulation based on the population VOT distribution which is shown to be superior through numerical analysis. Both static and dynamic toll setting algorithms are developed based on the proposed lane choice model, and their performance is compared (under deterministic traffic behavior) in regards to the performance of an HOT facility.
  Authors: Gardner, Lauren; Bar-Gera, Hillel; Boyles, Stephen
  Authors: Gardner, Lauren; Bar-Gera, Hillel; Boyles, Stephen
  Year: 2013
  Document Type: Paper
  Subject: Finance; Operations and Traffic Management; Policy
  Session: 294
  Paper Number: 13-2368
• Figure-Eight Hysteresis Pattern in Macroscopic Fundamental Diagrams for Urban Freeway Network in Beijing, China
  Abstract: This paper presents Macroscopic Fundamental Diagrams (MFDs) for an urban freeway network in Beijing, China. In the diagrams, a figure-eight hysteresis pattern is clearly observed. To understand the causes, analyses are made ranging from spatialtemporal heterogeneity of vehicles to the flow-occupancy relation for individual locations. As a result, we observe at individual locations that free-flow traffic with the same occupancy exhibits different flows in the onset and offset of congestion; it is attributed to the figure-eight hysteresis pattern at the macroscopic level. The formation of the multi-branch flow-occupancy diagram at individual locations is discussed and explained. The paper enriches the knowledge about MFDs and provides some empirical support for the existing theory.
  Authors: He, Zhengbing; He, Shuyan; Guan, Wei
  Authors: He, Zhengbing; He, Shuyan; Guan, Wei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 213
  Paper Number: 13-1760
• Two-Step Optimization Model for Dynamic Lane Assignment at Isolated Signalized Intersections
  Abstract: At isolated signalized intersections, the congestion problem is partly caused by the unbalance of supply and demand which may be due to the variability of turning movement volumes. Although the signal timing can be adjusted to handle varying demand, its effect alone is limited, especially when the traffic demand fluctuates significantly. This paper presented a two-step optimization model for dynamic lane assignment to overcome this shortcoming of static lane markings and fully utilize the existing traffic facilities. The first step was to obtain the best lane assignment scheme by an arm-group based Integer-Non-Linear-Program model. The second step was to identify a suitable implementation scheme by determining a binary-type threshold. The results of VISSIM simulation showed that the proposed model could smartly choose the occasion to change the lane assignment by ignoring the small volume fluctuation and improve the traffic operation effectively when the traffic demand varies significantly.
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-1882
• Global Optimization Method for Robust Pricing of Transportation Networks Under Uncertain Demand
  Abstract: We extend the existing toll pricing studies with fixed demand to stochastic demand. A new and practical second-best pricing problem with uncertain demand is proposed and formulated as a stochastic mathematical program with equilibrium constraints. In view of the problem structure, we develop a tailored global optimization algorithm. This algorithm incorporates a sample average approximation scheme, a relaxation-strengthening method, and a linearization approach. The proposed global optimization algorithm is applied to three networks: a two-link network, a seven-eleven network and the Sioux-Falls. The results demonstrate that using a single fixed estimation of future demand may overestimate the future system performance, which is consistent with previous studies. Moreover, the optimal toll obtained by using the mean demand value may not be optimal considering demand uncertainty. The proposed global optimization algorithm explicitly captures demand uncertainty and yields solutions that outperform those without considering demand uncertainty.
  Authors: Wang, Shuaian; Gardner, Lauren; Waller, S. Travis
  Authors: Wang, Shuaian; Gardner, Lauren; Waller, S. Travis
  Year: 2013
  Document Type: Paper
  Subject: Finance; Operations and Traffic Management; Policy
  Session: 294
  Paper Number: 13-1961
• Left-Turn Driver Behavior During Permissive Interval of Protected-Permissive Operation Based on Signal Display
  Abstract: A study was conducted to assess the differences in operations and driver behavior when drivers were confronted with three different signal displays for the permissive interval of a protected/permissive left-turn (PPLT) phase. A comparative two-phased approach, based on field observations of driver behavior and actions recorded on video, was used to conduct this research. The Phase I research examined driver behavior at six intersection approaches in Peoria, Illinois operating with different permissive left-turn displays: circular green (CG), flashing yellow arrow (FYA) and flashing red arrow (FRA). The results of the Phase I research found that the FYA had the highest proportion of drivers’ safe and efficient actions combined as compared to the CG and FRA displays. In Phase II, a comparative analysis of four intersection approaches was conducted to determine the impacts on driver understanding of the permissive left-turn circular green display in two geographic areas: one area Peoria, Illinois that uses multiple permissive left-turn signal indications for the PPLT phase (CG, FYA, and FRA) and the second area Bloomington, Illinois that only uses the circular green indication. The results of the Phase II research found that there were no differences in driver understanding of the circular green permissive left-turn display between the two areas, based on the observed safe and efficient driver actions.
  Authors: Rietgraf, Ashley Rose; Schattler, Kerrie L.
  Authors: Rietgraf, Ashley Rose; Schattler, Kerrie L.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-2119
• Reliability Analysis of Traffic Signal Lights Using Fuzzy Reliability Theory
  Abstract: Over the past decade, many municipalities have begun to replace incandescent lamps in their traffic signals with light emitting diode (LED) arrays. While LED technology boasts longer lifetimes and superior performance over their counterparts, there are many limitations involved in both testing and evaluating their reliability. As such, an analysis used to evaluate the reliability of traffic signal lamps along a corridor is proposed. The purpose of the analysis was to determine the impact of LED arrays and incandescent lamps on this performance. To accomplish this task, the progression of the reliability assessment from individual lamp to the entire signal light system for a corridor is demonstrated. Furthermore, to overcome the lack of a crisp transition of a signal light system for a corridor from a success to failure state, profust or fuzzy reliability theory is employed. The results of the study indicated that the estimated reliability for a case study corridor was extremely high using the projected reliability of the signal lamps, particularly influenced by installed LED arrays. The results, coupled with field observations of partial burnouts of LED arrays and prior investigations revealing a lower than anticipated reliability of LED arrays in signal systems, suggest that manufacturer-established reliability assessments likely overestimate the true reliability of these fixtures. As such, it is recommended that fuzzy reliability theory be used to more effectively and accurately assess the reliability of individual LED arrays. Finally, as a case study of the proposed methodology, the process of modeling the reliability of signal lamps for an entire corridor is presented along with the results.
  Authors: Machemehl, Randy B.; Zhang, Zhanmin
  Authors: Machemehl, Randy B.; Zhang, Zhanmin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 336
  Paper Number: 13-2151
• Exploration of Lane Changing Behavior on Freeways
  Abstract: Lane changing has received much attention as it is a significant component of microscopic traffic simulation. Many studies have focused on the details of the lane change maneuver from external observation based data which do not consider the type of driver performing the maneuver. This study related the physical details of freeway lane changing to the type of driver performing the maneuver. 46 research participants drove an instrumented vehicle and performed a combined total of 726 freeway lane changes. Each research participant was categorized into one of four groups ranging from conservative to aggressive. The data were analyzed to identify any trends between the different driver types and their lane changing characteristics, specifically lane change duration and gap acceptance characteristics. It was found that, in general, more conservative drivers have greater lane change durations than aggressive drivers. The gap acceptance comparison among driver types did not yield any conclusive trend. In addition, distributions were fitted to lane change duration and gap acceptance histograms. The results suggest that driver types impact freeway lane changing. Therefore, this relationship should not be disregarded when developing lane changing models.
  Authors: Hill, Corey Alan; Elefteriadou, Lily
  Authors: Hill, Corey Alan; Elefteriadou, Lily
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2199
• Sensitivity of Evacuation Performance Estimates to Evacuee Route Choice Behavior
  Abstract: The objective of this paper is to illustrate the sensitivity of evacuation travel time estimates with respect to the assumptions made regarding evacuee route choice behavior. The user equilibrium (UE) assignment procedure in which evacuees are assumed to choose the shortest (or fastest) path from their origins to destinations is considered as the base case. Very few studies have documented the actual route choice behavior of evacuees during a hurricane. These studies were used to develop realistic route choice behavior assumptions - the different types of route choices and proportion of evacuees for those types. The impact of route choice behavior on evacuation performance, especially travel times, was then explored using a large-scale regional simulation model of the Hampton Roads region in Virginia. The model was developed in an earlier study using real-world network data and actual evacuee behavioral data. The analysis indicated that using UE to generate average travel time estimates for evacuation planning significantly underestimates the actual travel times realized during an evacuation. The extent of underestimation of evacuation travel times depends on the total evacuation demand (a function of storm intensity), and the percent of evacuees willing to use en-route information to seek alternate routes when facing congestion. For the three en-route percentages reported in the literature i.e., 30%, 50%, and 70%, the UE travel times were 48%, 37%, and 29% lower than actual travel times realized in a category 1; 99%, 78%, and 63% lower in a category 2; and 88%, 72%, and 52% lower in a category 3 evacuation.
  Authors: Fang, Lei; Edara, Praveen
  Authors: Fang, Lei; Edara, Praveen
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 772
  Paper Number: 13-2227
• Work Zone Lighting and Visual Performance: Analysis and Demonstration
  Abstract: In part because of the potential for high levels of glare from work zone illumination, recommendations for light levels from work zone illumination systems are substantially higher than levels used along roadways in non-work-zone locations. In a two part study, requirements for work zone illumination light levels were assessed. First, levels for workers varying in age from 20 to 60 years were evaluated using the relative visual performance model, with and without the presence of visibility-reducing glare. Except for the smallest, lowest-contrast tasks performed by the older age workers, an illuminance of 10 lx resulted in visibility well above the threshold even in the presence of glare, and an illuminance of 30 lx resulted in suprathreshold visibility for these conditions as well. The results of these computational analyses were largely confirmed in a full-scale, outdoor field demonstration attended by transportation agency engineers and highway contractors. Together, the findings suggest that when lighting systems provide sufficient glare control, light levels do not always need to be especially high to ensure adequate visibility by workers.
  Authors: Bullough, John D.; Besenecker, Ute; Snyder, Jeremy D.; Skinner, Nicholas P.
  Authors: Bullough, John D.; Besenecker, Ute; Snyder, Jeremy D.; Skinner, Nicholas P.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-2244
• Evacuation in Large-scale Transportation Network: A Bi-Level Control Method with Uncertain Arterial Demand
  Abstract: To improve the efficiency of large-scale evacuation, a network aggregation method and a bi-level optimization control method are proposed in this paper. The network aggregation method indicates the uncertain evacuation demand on the arterial sub-network and balances accuracy and efficiency by refining the local road sub-networks. The bi-level optimization control method is developed to reconfigure the aggregated network from both supply and demand sides with contraflow and conflict elimination. The main purpose of this control method is to make the arterial sub-network to be served without congestion and interruption. Then, a corresponding bi-objective network flow model is presented in a static manner for an oversaturated network, and a GA-based solution method is used to solve the evacuation model. The numerical results from optimizing a city-scale evacuation network for a super typhoon justify the validness and usefulness of the network aggregation method and optimization control method.
  Authors: Hua, Jingyi; Ren, Gang; Cheng, Yang; Yu, Chen; Ran, Bin
  Authors: Hua, Jingyi; Ren, Gang; Cheng, Yang; Yu, Chen; Ran, Bin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-2254
• Performance Assessment on Noncoordinated Signalized Arterials and Guidelines for Signal Coordination
  Abstract: This paper introduces a probabilistic model for calculating the expected number of stops on non-coordinated arterials. The model can be applied to developing a practical guideline for determining when the signals in an arterial should be coordinated. The main assumption of the model is that the probability of making a stop is a function of the effective green to the cycle length ratio which also relates to the traffic volume and capacity. Various sources made recommendations in terms of the traffic volume, platoon dispersion, and signal spacing, concerning when a coordination plan should be implemented. However, none of them considered the number of stops as a factor. We propose a stop-based guideline using the probabilistic model, stating that an arterial should be coordinated if the number of stops exceeds 50%. An arterial does not need to be coordinated when the number of stops falls below 20%, and engineering judgment should apply between these two thresholds. A case study using a VISSIM simulation was conducted to validate the probabilistic model and the proposed guideline in order to test its practicality. The results confirmed that the probabilistic model is highly reliable in estimating the number of stops, thus the developed guideline proved to be practical in considering both the main street and side street performances.
  Authors: Andalibian, Rasool; Zong, Tian Z.; Wu, Ning; Farivar, Saeedeh
  Authors: Andalibian, Rasool; Zong, Tian Z.; Wu, Ning; Farivar, Saeedeh
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-2258
• Data-driven Evaluation of Freeway Service Patrol in Low-traffic Areas Using Discrete-Event Simulation
  Abstract: The freeway safe service patrol (FSP) is a low-cost but effective approach to identifying and clearing incidents quickly. This service has been deployed in most states of US. There is also rich literature on evaluation of the freeway service patrols, most of which focused on evaluating the travel time and the derived capital savings due to the reduction of incidents clearance time. However, although the non-recurrent travel delay is a major concern in metro areas, the primary goal of FSP in many other low-traffic areas is to assist stalled vehicles effectively and reliability with certain resource constraints. Few evaluations in the past were conducted from the operational perspective, such as the FSP crew¡¯s responding reliability, fuel consumption, vehicle mileage or fleet maintenance cost in various scenarios. Using a discrete-event simulation method, this paper presents an operational evaluation framework for of the FSP in low-traffic areas. Lastly, as an illustration, the reliability of SAFE Patrol program in Kentucky, which only serves rural areas in Kentucky, was evaluated and estimated under various scenarios.
  Authors: Li, Pengfei; Walton, Jennifer
  Authors: Li, Pengfei; Walton, Jennifer
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 337
  Paper Number: 13-2263
• 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
• Corridor Management of Large Planned Special Events: Integrated Optimization of Park-and-Ride and Bus Contraflow Measures
  Abstract: To improve the corridor efficiency during large planned special events, an integrated strategy with Park-and-ride (P&R) and bus contraflow is presented in this paper. This strategy eases the safety or performance limitations of the two congestion mitigation measures applied alone. A qualitative analysis first shows that P&R measure increases the transit demand on bus contraflow lane, while bus contraflow measure provides an express and non-congested service to P&R users. Then, a P&R facility location method is developed to search for the optimal P&R facility site. And a simulation corridor network is used to compare the performance of the proposed integrated strategy with the normal operation and the conventional P&R strategies, in four scenarios and with five groups of assumptions. The simulation results and measure of effectiveness (MOE) analysis indicate the benefits and applicability of the proposed integrated strategy.
  Authors: Hua, Jingyi; Ren, Gang; Cheng, Yang; Huang, Zhengfeng; Ran, Bin
  Authors: Hua, Jingyi; Ren, Gang; Cheng, Yang; Huang, Zhengfeng; Ran, Bin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 807
  Paper Number: 13-2271
• Development and Investigation of a Dynamic Eco-Driving Speed Guidance Strategy for Signalized Highway Traffic
  Abstract: During driving on the signalized highway corridors, the signal timing and vehicle positioning information can be provided under connected-vehicle environment. This paper developed a dynamic eco-driving speed guidance strategy (DESGS) which yields the most fuel/emission-optimal speed profile for a vehicle approaching signalized intersections. An optimization-based rolling horizon and a dynamic programming approach for tracking the optimal guided velocity for individual vehicle are put forward, and also a vehicle specific power based approach to estimate fuel consumption and CO2 emissions was integrated in the DESGS. To evaluate the effectiveness of the overall strategy, 15 typical drivers were recruited to attend the speed guidance experiments using multi-vehicle driving simulators. It was found that the number of stops is significantly reduced and fuel consumption and CO2 emissions can be reduced by 25% for the vehicles with eco-speed guidance as compared to the vehicles without speed guidance.
  Authors: Sun, Jian; Niu, Dening; Chen, Shenyang; Li, Keping
  Authors: Sun, Jian; Niu, Dening; Chen, Shenyang; Li, Keping
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-2272
• Estimating Queue Distance Under Connected Vehicle Technology: Using Probe Vehicle, Loop Detector, and Fused Data
  Abstract: With the emergence of the Connected Vehicle technology, estimating the queue distance using probe trajectory data has recently received considerable attention. Different from data collected at loop detectors, probe trajectory data can provide a lower bound on the queue distance even if the market penetration rate is low. In this paper, we develop an event-based method that uses both probe trajectory and signal timing data to estimate the queue length. The estimation accuracy under different market penetration rates is then examined. We also develop a data fusion method that combines probe trajectory data and loop detector data. We then investigate when the data fusion method is expected to work well. Case studies are conducted using microscopic simulation data, and some observations are made.
  Authors: Li, Jing-Quan; Zhou, Kun; Shladover, Steven E.; Skabardonis, Alexander
  Authors: Li, Jing-Quan; Zhou, Kun; Shladover, Steven E.; Skabardonis, Alexander
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-2274
• 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
• Development of Freight Demand Generation Model: Application to California with Validation
  Abstract: The growth in freight transportation demand prompts the development of better tools to evaluate and analyze goods movement. Tools such as freight demand generation models can improve decision-making through the analysis of the types and quantity of goods moved from one point to another. This paper concerns with the disaggregation of the Federal Highway Administration’s Freight Analysis Framework database (version 3.0) on freight origin-destination data and the development of linear regression equations to describe the relationships between commodity-based productions/attractions to specific economic variables. Instead of generating a production/attraction equation for each commodity, the grouping of commodities can simplify model development and application. We consider three grouping methods and two model selection criteria (with and without intercepts). Commodity equations with high R2 values were more likely to generate outputs closer to the actual 2007 data in the calibration process. In addition to the discussion of model selection and commodity grouping, the freight generation models are further validated using county-level economic data in California and applied to predict 2015 commodity outputs. This study can be used as a guideline for city, county, metropolitan and state level planning agencies to develop their own customized freight demand generation model.
  Authors: Lim, Robert; Qian, Zhen; Zhang, H. Michael
  Authors: Lim, Robert; Qian, Zhen; Zhang, H. Michael
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-1937
• Simulation of Arterial Traffic Using Cell Transmission Model
  Abstract: Cell transmission model (CTM) is one of the widely used macroscopic traffic models. There was a lot of research to show this model could provide reliable simulation of freeway traffic and it has many applications in traffic management design. But there was insufficient proof to demonstrate this model can accurately simulate urban traffic. This paper illustrates the use of cell transmission model on a segment of signalized arterial. The data source is the NGSIM data collected on Lankershim Blvd. The simulation result agrees with the measurement.
  Authors: Su, Dongyan; Kurzhanskiy, Alex; Horowitz, Roberto
  Authors: Su, Dongyan; Kurzhanskiy, Alex; Horowitz, Roberto
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2387
• Hotspot Identification Under Limited Information: Combined Probabilistic and Fuzzy Cluster-Based Approach
  Abstract: Hot-Spot Identification (HSID) requires crash history information such as annual crash counts, their severities etc and details such as annual traffic exposure and geometric design details. The most recommended HSID method— Empirical Bayes utilizes at least crash history and traffic volume information to develop Safety Performance Function (SPF), which is used to compute expected number of crashes at a given site. However, in the absence of systematic data collection and maintenance, information about geometric design and traffic volume is not only difficult to obtain, but also demands significant resources. In such circumstances, only crash-count based (CCB) HSID techniques, such as Crash Frequency (CF) method, Fatal Crash Frequency (FCF) method and Equivalent Property Damage Only (EPDO) methods may only be adopted even with their known limitations. In this article, the authors suggested a new method of HSID, using disaggregate crash history information in crash severity model. Based on the probabilities of crash severities by the major contributing factors, expected numbers of severe and fatal crashes are calculated. These expected crash counts are used to classify locations into two fuzzy clusters— a) black-spots and b) white-spots using Fuzzy C-Means (FCM) algorithm. The identified hotspots are ranked based on their mean departure from core of the hotspot cluster. Site consistency, Method consistency and Total rank differences tests are used to compare the performance of the method with other CCB-HSID techniques. Results show the robustness of the proposed FCM method as it performs well in all consistency tests.
  Authors: Bandyopadhyaya, Ranja; Mitra, Sudeshna
  Authors: Bandyopadhyaya, Ranja; Mitra, Sudeshna
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-2379
• Observations and Analysis of Multistep Approaching Lane Changing Behavior at Two Expressway Merge Bottlenecks in Shanghai
  Abstract: From numerous field observations at two expressway merge bottlenecks, the paper identifies and studies a peculiar lane changing behavior, multistep approaching lane changing (MALC), at these bottlenecks. The characteristics of and detailed maneuvers in the MALC process are first described and compared with other three traditional lane changing behaviors (normal, cooperative and forced lane changing). Next, descriptive parameters such as lane-changing duration time, velocity and affected vehicle numbers from 132 sets of vehicle trajectory data collected at two merge bottlenecks in Shanghai, China are investigated and analyzed during the so-called trans-line ride (TLR) period. Significant differences are found between MALC and the traditional lane changing behaviors: MALC takes longer to complete (10s on average), involves lower lane changing velocity (15km/h on average during TLR period) and affects more vehicles (6 vehicles on average). As such, MALC poses more disruptive influences on the traffic flow, and could explain the occurrences of rapid capacity drop at expressway merge bottlenecks.
  Authors: Zhao, Li; Sun, Jian; Zhang, H. Michael
  Authors: Zhao, Li; Sun, Jian; Zhang, H. Michael
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-2400
• Generalized Minimum Cost Flow Model for Multiple Emergency Flow Routing and Optimal Contraflow Design
  Abstract: During real-life disasters, such as earthquakes, floods, terrorist attack and other unexpected events, emergency evacuation and rescue are two main operations to save affected people¡¯s life and property. It is unavoidable that evacuation flow and rescue flow will conflict with each other on the same spatial road network and in the same time window. We proposed a generalized minimum cost flow model to optimize the distribution pattern of these two kinds of flow on the same network by introducing the conflict cost. The travel time on each link is assumed to be subject to BPR function rather than a fixed cost (such as link length or free flow travel time). Also, we integrate contra-flow operations into this model to re-design the shared network by those two kinds of flow. Consequently, a non-convex mixed integer non-linear programming model with bilinear, fractional and power items is constructed. GAMS/BARON is used to solve this programming model, and a case study is performed in downtown area of Harbin city in China to verify the efficiency of proposed model. Several helpful findings and managerial insights are also presented.
  Authors: An, Shi; Cui, Jianxun; Wang, Jian; Zhao, Meng
  Authors: An, Shi; Cui, Jianxun; Wang, Jian; Zhao, Meng
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-2438
• Reliable Game Model for Network Violator Interception Problem
  Abstract: This paper focuses on planning interceptor locations in a general transportation network to maximize the expected benefits from catching violators mixing in public traveler flow. We use travel distance of violators before intercepted and innocent public traveler flow encountered by violators to define the expected benefit by setting interceptors along a specific route. Two reliability-related characteristics are also integrated into the planning model to make it more practical. One is each interceptor (maybe a sensor, a checkpoint or something else) have a failure probability. Different failure scenarios may incur different layout decision of interceptors and investigation of failure can lead to a more reliable solution. The other is there is a ¡°game¡± between interceptor planner and violators. We assume violators will adjust their route choices according to the interceptor layout decided by planner. Logit choice model is used to account for the route adjustment conducted by violators. Consequently, a non-linear non-convex binary integer programming model is presented. We develop a Simulated Annealing (SA) algorithm to solve it. A set of numerical experiments are conducted to illustrate the computational efficiency of the proposed algorithm. Further, we analyze the sensitivity of disruption probability of interceptors to optimal objective function values and discuss how to determine the values of parameters in violator route choice model.
  Authors: An, Shi; Cui, Jianxun; Wang, Jian
  Authors: An, Shi; Cui, Jianxun; Wang, Jian
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-2431
• Design and Implementation of Emergency Vehicle Signal Preemption System Based on Cooperative Vehicle-Infrastructure Technology
  Abstract: Emergency vehicle such as ambulance or fire truck is an important part of traffic flow. The efficiency, reliability and safety of emergency vehicle operations dropped due to increasing traffic congestion. This paper describes the design and implementation of an Emergency Vehicle Signal Preemption System (TJ-EVSP) in a Cooperative Vehicle-Infrastructure System (CVIS) environment. The system function, system architecture and operation strategies were presented. Then, the system was deployed and validated at two adjacent intersections in Taicang City, Jiangsu Province. Results show that the proposed system can improve the efficiency of emergency vehicle operations with less waste of traffic resources.
  Authors: Wang, Yinsong; Yang, Xiaoguang; Huang, Luoyi; Zhang, Lun
  Authors: Wang, Yinsong; Yang, Xiaoguang; Huang, Luoyi; Zhang, Lun
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 674
  Paper Number: 13-2494
• Short-Term Freeway Travel Time Prediction with Self-Tuning Regulator in a Robust Adaptive Control System
  Abstract: Accurate short-term travel-time prediction is crucial to the advanced traveler information and route guidance system. Since the travel time fluctuations can be viewed as a time-varying stochastic process due to unforeseen events (e.g., heterogeneous driver behaviors, incidents, accidents, or bad weather), travel time prediction requires an approach that is capable of capturing the uncertainties. This paper presents a Bayesian forecasting-based generalized dynamic linear model (DLM) with time-varying parameters and robust self-tuning regulator (TRDLM) embedded in an adaptive control system for online short-term travel time prediction. The proposed TRDLM model employs a discrete hidden Markov model (HMM) to determine traffic state transition, and then utilizes the robust self-tuning regulator to dynamic adjust the parameters, so as to improve the prediction accuracy. The proposed methodology is tested on a real world traffic road stretch in Beijing, China using automatic license plate recognition data. The computation results are also compared with a traditional time series method (Autoregressive Integrated Moving Average Model (ARIMA)). The experimental results illustrate the effectiveness of the proposed methodology and suggest that the proposed method can provide accurate and reliable travel time prediction under various traffic conditions.
  Authors: Wang, Feng Juan; Fei, Xiang; Zhang, Xin; Wang, Baohua; Fan, Liya
  Authors: Wang, Feng Juan; Fei, Xiang; Zhang, Xin; Wang, Baohua; Fan, Liya
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-2497
• Improving Traffic Flow Efficiency by In-Car Advice on Lane, Speed,and Headway
  Abstract: This paper presents the in-car advisory system Connected Cruise Control. The system gives advises, which are determined at a traffic management centre based on the traffic state, in order to prevent or solve suboptimal traffic flow conditions. The current system aims at an optimal lane distribution in high flow conditions and a reduction of the capacity drop by advising drivers to maintain a short (but safe) headway at the end of congestion. The system is implemented in microscopic simulation to evaluate the potential benefits for different penetration and compliance rates. Benefits at both low and high rates are found as only a small redistribution of traffic over the lanes may be required to stabilize flow. The capacity drop is effectively reduced at high rates only as it is required that many vehicles accelerate more. The maximum benefit found is a reduction of 48% in travel time delay. Effects are smaller at lower rates. A negative side effect which is found is that increasing flow on the right lane may increase the impact of spillback from an off ramp. Several options are proposed to reduce or circumvent this.
  Authors: Schakel, Wouter; van Arem, Bart
  Authors: Schakel, Wouter; van Arem, Bart
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2500
• Estimation of Inventory-Theoretic Model of Mode Choice in Freight Transport
  Abstract: A model of freight mode choice is developed on the basis of the economic order quantity model, an inventory theoretic model of optimal shipment size. Shipment size is not explicit in the mode choice model; however the specifications of the utilities associated to each transport mode account for the fact that shipment size and transport mode are two related decisions, which depend on transport costs and on the logistic costs of shippers. The explanatory variables of the mode choice model are: the total commodity flow between the shipper and the receiver, the distance between the origin and the destination, the value density of the commodity, and a few additional variables. No transport supply data is used.Four similar versions of the model are estimated using the French shipper survey ECHO. As a result of these estimations, the terms of the utility functions inspired from inventory theory substantially improve the statistical goodness-of-fit of the models. The approach taken in this paper illustrates the potential of inventory theory to improve freight mode choice modeling. It also shows that the commodity flow between the shipper and the receiver is an important explanatory variable of mode choice, and insists on the fact that this variable should be observed in shipper surveys.
  Authors: Lloret-Batlle, Roger; Combes, François
  Authors: Lloret-Batlle, Roger; Combes, François
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-2513
• Lane-Based Breakdown Identification Method at Diverge Sections for Modeling Breakdown Probability
  Abstract: As for modeling breakdown probability on expressways, identification of breakdown occurrence is a decisive issue. To date, most of the existing identification methods have treated all lanes of mainline as one unit for a facility, and are conducted mainly through a check of the aggregated data of cross-section. However, this cross-section based method is oversimplified for bottlenecks at expressway facilities where lane usage preferences of each lane significantly differ like nearby diverge sections.Therefore, a lane based method is proposed to identify breakdown on each lane, and timing of breakdown occurrence is determined by a critical speed which is optimized through obtaining most significant speed drops accompanying with breakdown occurrences. The proposed lane based method is applied to four bottlenecks at diverge sections on intercity expressways in Japan. Superiorities of lane based method are highlighted as follows. Firstly, it can identify and exclude semi-congested cases where some lanes are congested and others are not. At a diverge section of Toyota JCT, 15 semi-congested cases are checked out through lane based method among 198 breakdown events which are identified by using cross-section based method. Secondly, timing of breakdown occurrence can be appropriately determined by lane based method which applies to 34 cases for this diverge section at Toyota JCT. These superiorities significantly improve accuracy of extracting breakdown flow rates which are underestimated by the existing cross-section based method. Breakdown probability is modeled by using the extracted breakdown flow rates through lane based method, and impacts of traffic condition characteristics are discussed. Diverge rate and lane utilization rate are found to have significant impacts on breakdown probability at diverge sections.
  Authors: Danpeng, Ma; Nakamura, Hideki; Asano, Miho
  Authors: Danpeng, Ma; Nakamura, Hideki; Asano, Miho
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-2514
• Influence of Psychological Factors on Acceptability of Congestion Charging in China
  Abstract: This paper investigated the psychological factors influencing the acceptability of an assumed congestion charge scenario in Nanjing. To analyze factors important for the acceptability, we proposed a two-stage hierarchical model. A questionnaire study was conducted among 897 car users. Results showed that perceived effectiveness and fair were the determinants of congestion charge acceptability, which confirmed previous findings and supported transferability of results. In contrast to previous studies, personal norm was not significantly related to the acceptability, but willing to reduce car use had a positive association with acceptability. The lesson for policy makers was that when implementing congestion pricing, it was important to propagandize the effectiveness of the measure in solving perceived urgent problems and to guarantee people feel to be treated just in comparison to others.
  Authors: Sun, Xianglong
  Authors: Sun, Xianglong
  Year: 2013
  Document Type: Paper
  Subject: Finance; Operations and Traffic Management; Policy
  Session: 294
  Paper Number: 13-2530
• Feedback Perimeter Control for Multiregion and Heterogeneous Congested Cities
  Abstract: It was recently observed from empirical data that by aggregating the highly scattered plots of flow versus density from individual loop detectors for city regions with homogeneous spatial distribution of congestion, the scatter almost diminishes and a well-defined Macroscopic Fundamental Diagram (MFD) exists between space-mean flow and density. These results can be of great importance to unveil simple and robust perimeter control policies in such a way that maximizes the network capacity and outflow. Single region perimeter control might not be optimal if there is a significant number of destinations outside the region of analysis or if the city is heterogeneously loaded. This paper integrates an MFD modeling to perimeter control optimization for large-scale cities with multiple centers of congestion, if these cities can be partitioned in a small number of homogeneous regions. Perimeter control actions may be computed in real-time through a linear multivariable feedback regulator or a linear multivariable integral feedback regulator. The impact of the perimeter control actions to a three-region urban network is demonstrated via micro-simulation. A key advantage of this approach is that it does not require high computational effort and future demand data if the state of each region can be observed.
  Authors: Aboudolas, Konstantinos; Geroliminis, Nikolas
  Authors: Aboudolas, Konstantinos; Geroliminis, Nikolas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 828
  Paper Number: 13-2571
• Empirical Assessment of Traffic Management Effects of Variable Speed Limit System on German Autobahn: Before and After
  Abstract: This paper presents findings of an empirical study focusing on the traffic flow effects of a variable speed limit (VSL) system on a three-lane German Autobahn. It integrates loop detector data as well as VSL and driver information data provided by means of overhead dynamic message signs along a 16.3-km section of Autobahn 99 near Munich, Germany. Unlike most VSL deployments, these data sources allow for a "with and without" analysis reflecting traffic flow and driver behavior in the presence of as well as in the absence of the VSL system deployment. In addition to speed, the primary features of interest were the spatial-temporal extent of the queue (congestion), the flow changes caused by indentified bottlenecks, the distribution of flow across lanes, the percent trucks per lane as well as the flow homogeneity between lanes. The analysis recorded bottleneck flow reductions that were balanced across all lanes in the case of an active VSL system. In case of an inactive VSL system the flow reductions were slightly lower and primarily occurred in the center and the shoulder lane while there was even a small flow increase in the median lane. Further examination indicated that the gain in homogeneity and safety in the "with" case is at the cost of capacity. Toward that end, possible reasons for the differences between the "with" and "without" cases have been found. Those are based on the fact that a truck overtaking ban is in effect when the driver information system is active.
  Authors: Weikl, Simone; Bogenberger, Klaus; Bertini, Robert Lawrence
  Authors: Weikl, Simone; Bogenberger, Klaus; Bertini, Robert Lawrence
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 778
  Paper Number: 13-2580
• Evaluation of the Functionally Hierarchical Road Network Considering Junction Types
  Abstract: A concept of the functionally hierarchical road network has been recognized since long ago, with the purpose of achieving higher network efficiency. In Japan, practical use of this concept is increasingly being demanded against the problems such as longer delay on arterial roads and larger flow of passing-through traffic on local roads. For that, the quantitative effects of typical measures of functional hierarchy, such as conversion of junction types need to be quantitatively demonstrated. Therefore, this study aims to evaluate the functionally hierarchical network considering the impact of junctions. The network is evaluated from two viewpoints: the performance of individual road levels and the performance of an entire network, by using several indices such as travel speed and use rate by through traffic on individual road levels. Since the existing methodologies cannot deal with the impacts of converting junction types on the travel speeds under the interaction with usersf route choice implicitly, an original UE assignment which takes into account junction delay by type is proposed. By applying it, a case study with hypothetical grid network showed that replacement of key signalized intersections between highest-level roads with overpasses is quite significant to form functional hierarchy and further improve the performance of the entire network. Additionally, it is also verified that junction treatment is more effective to improve mobility than enhancing of link free-flow speed under the network with dense signalized intersections.
  Authors: Goto, Azusa; Nakamura, Hideki; Asano, Miho
  Authors: Goto, Azusa; Nakamura, Hideki; Asano, Miho
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-2535
• Reliability Benefits of Active Traffic Management: Managed-Lanes Case on French Urban Motorway
  Abstract: Traffic management aims to ensure a high quality of service for a maximum of users, by decreasing congestion and increasing safety. However, uncertainty regarding travel time (TT) decreases the quality of service and leads end-users to modify their plans regardless of the average TT. Indicators describing TT reliability are being developed and should be used in the future both for the optimization and for the assessment of active traffic management operation. This paper describes a managed lane experience on a motorway weaving section in France - Hard Shoulder Running (HSR) operation at rush hours. The paper describes the data measurement and the missing data replacement process. It focuses, however, on TT reliability indicators and on their use for reliability assessment on the basis of an observational before/after study. It provides some discussions on the advantages and drawbacks of reliability indicators under different traffic conditions. Indeed, the before/after study reports not only the effect of HSR but also of a speed limit campaign (SLC) which affected the free flow travel time. The study particularly shows the difference between using buffer times or buffer indexes. The paper also discusses the difficulty of interpreting the skew of TT distribution for travel reliability.
  Authors: Bhouri, Neila; Aron, Maurice
  Authors: Bhouri, Neila; Aron, Maurice
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-2531
• Measuring User Awareness at Signalized Intersections
  Abstract: Drivers have limited awareness of changes in trip attributes or the performance of the traffic system. Due to non-utilitarian behavior and perceptual biases a distinctive amount of changes go unnoticed or are valued incorrectly, which makes drivers indifferent to changing traffic conditions to a certain extent. Quantifying user awareness and understanding the probability of behavioral response to changes is valuable input for road operators and traffic engineers designing traffic management measures. This paper presents the results of a field study on user awareness at signalized intersections. The study focused on the ability of drivers to observe and rightly value differences in the timing of traffic lights. Measurements of actual waiting times were compared with perceived waiting times derived from interviews. Results show that drivers’ perception of waiting time was on average fairly accurate, but widely variable, and that waiting times were systematically underestimated. Remarkably, the classification of deviations from the average waiting time showed that the vast majority of the respondents considered their waiting time ‘normal’ or shorter than they were used to. Although in terms of representativeness field studies are believed to be of great importance to perception studies, the selected approach for this study did not provide the expected data. Therefore it was not possible to provide definite answers related to user awareness at signalized intersections. Advantages, disadvantages and lessons learned are discussed in the paper and have been incorporated in a follow up study as much as possible.
  Authors: Vreeswijk, Jaap; van Berkum, Eric; van Arem, Bart
  Authors: Vreeswijk, Jaap; van Berkum, Eric; van Arem, Bart
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 546
  Paper Number: 13-2612
• Travel Time Estimation for Signalized Arterials Using Probabilistic Modeling
  Abstract: Travel time is an important performance measure for transportation facilities. The objective of this research is to develop a model for estimating travel time for signalized arterials using probabilistic modeling. The model provides travel time based on the cycle length, green times, link lengths, maximum operating speed, offsets, acceleration/deceleration rate, and the per lane entering flow rate at each intersection. Results from the model were compared to a field data-calibrated simulator, and it was concluded that travel times from the simulation and the analytical model are similar and have similar trends. Increases in the g/C ratio and the acceleration/deceleration rate result in decreasing travel time. The impacts of other factors, such as link length, speed, and flow rate are not consistent: they mostly depend on the prevailing offsets. It was concluded that the analytical model can estimate the arterial travel time and its variability with reasonable accuracy.
  Authors: Li, Zhuofei; Elefteriadou, Lily
  Authors: Li, Zhuofei; Elefteriadou, Lily
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-2614
• A Coordinated Optimization Model for Signal Timings of Full Continuous Flow Intersection
  Abstract: Continuous flow intersection was invented by Francisco Mier to improve traffic operation in the intersection that suffers from traffic problems caused by heavy left-turn movement. Although it has developed for 25 years, some real intersections have been built and have achieved good results, there is no general model of signal timings and offsets for it. This paper (1) puts forward the main relationships that are needed to deal with in CFI model, then (2) builds a detailed model for optimization of phase sequence scheme, length of cycle, durations of each phase, and offsets between successive signals. (3) Comparison of the computing results of minimum cycle, capacity and average delay of CFI with conventional intersection. The results show that CFI has a clear advantage and this model has a wide range of application. The proposed model and algorithm also have the following two features: (1) location of the sub intersection as a design parameter need not be inputted but is affected by offset and queue length, (2) solving process and algorithms of all critical features such as average delay are provided. Because of simplified solving process, the computation is not enormous with the help of a simple procedure running on PC, so this model is easy for application.Keywords: continuous flow intersection; model for signal timings; queue length; average delay; evaluation.
  Authors: You, Xiaoming; Li, Li; Ma, Wanjing
  Authors: You, Xiaoming; Li, Li; Ma, Wanjing
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-2643
• Travel Time Reliability in Signal Control Problem: Simulation-Based Optimization Approach
  Abstract: Traffic signal control is a cost-effective way to make better use of the existing capacity of an urban transportation network. It is widely accepted that traffic signal benefits are not fully realized and there is plenty of room for improvement. The main purpose of this paper is to evaluate the potential of improving network reliability by using higher-order distributional information from detailed traffic simulators within signal control problems. In particular, higher-order travel time distributional information is used to derive signal plans that account for travel time reliability. In order to derive computationally efficient methods that embed non-efficient simulators, information from other more tractable traffic models is used throughout the optimization process. The role of these auxiliary models is to provide analytical structural information that enables good short-term algorithmic performance.The simulation-based optimization approach combines the information of expected link travel time with link travel time standard deviation. These two measures are used to address system efficiency and reliability considerations. The methodology is applied to the network of the Swiss city of Lausanne. Our approach proves that incorporating travel time reliability in the signal control problem would yield signal plans with reduced link travel time and reduced travel time variability.
  Authors: Chen, Xiao; Osorio, Carolina; Santos, Bruno Filipe
  Authors: Chen, Xiao; Osorio, Carolina; Santos, Bruno Filipe
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 828
  Paper Number: 13-2716
• Assessment of Dynamic Speed Limits on Freeway A20 near Rotterdam, Netherlands
  Abstract: On the freeway A20 near Rotterdam, the Netherlands, a trial with dynamic speed limits has started at June 28, 2011. On a stretch of 4.2 km the speed limit is increased from 80 km=h to 100 km=h as soon as congestion appears to set in and during the night. The aim of the dynamic speed limits is to improve the traffic operations without deteriorating the local air quality.This paper presents the assessment of this trial with respect to traffic operations, air quality, noise level and traffic safety.The traffic operations on the freeway A20 appear to have significantly improved due to the dynamic speed limits: a decrease in number of vehicle loss hours of 600 (or 20%). This improvement is mainly caused by an increase of the free flow capacity by 4% of the main bottleneck on the stretch. The dynamic speed limits cause a change in driver behavior such that the median lane is better occupied when flow increases.The air quality is slightly deteriorated. The effects vary along the stretch with a maximum increase in NOx and PM10 emission of 3.7% and 3.6% respectively. However, the effects on the average concentration of NOx per year are limited. The noise level appears to slightly increase with 0.2 dB. This increase is mainly caused during the two peak periods.The indicators for traffic safety show sometimes a (possibly) positive and sometimes a (possibly) negative effect. However, it is not likely that dynamic speed limits have a significant negative effect on traffic safety.
  Authors: Hoogendoorn, Serge; Daamen, Winnie; Hoogendoorn, Raymond Gerard; Goemans, Jan Willem
  Authors: Hoogendoorn, Serge; Daamen, Winnie; Hoogendoorn, Raymond Gerard; Goemans, Jan Willem
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 778
  Paper Number: 13-2736
• Use of HCM Freeway Facility Analysis and Microscopic Simulation Models as Part of Real-Time Management Decision Support Systems
  Abstract: Traffic management centers (TMCs) have successfully applied advanced management strategies to reduce incident impacts. However, the effectiveness of the management strategies can be enhanced by predicting, in real-time, the impacts of incidents based on the identified attributes of these incidents. This study investigates the implementation of macroscopic and microscopic traffic simulation models to estimate incident delays, as part of a real-time traffic management system. The two tools used in the investigation are FREEVAL, the computational engine of the Highway Capacity Manual 2010 (HCM 2010) and the CORSIM microscopic simulation tool. It can be concluded based on the results of this study that both CORSIM and FREEVAL are able to predict traffic delays due to incidents, however, the accuracy of prediction is affected by the accuracy of incident duration prediction and capacity drop estimates. The analysis also indicates that both models produce similar estimates of incident delays when the same analysis parameters are input to these two models, at least for the case studies investigated in this paper.
  Authors: Hadi, Mohammed; Xiao, Yan; Wang, Tao
  Authors: Hadi, Mohammed; Xiao, Yan; Wang, Tao
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 341
  Paper Number: 13-2783
• Considering Individuals with Disabilities in Building Evacuation: Agent-Based Simulation Study
  Abstract: Catastrophic events in the United States have highlighted numerous issues regarding effective emergency evacuations. In existing studies, individuals with disabilities have not been a significant feature of evacuation investigations due to the lack of empirical data and thus their evacuation needs have been generally overlooked. The purpose of this paper is to evaluate how effectively the built environmental accommodates the needs of individuals with disabilities during emergency evacuations. Specifically, we explored whether there is a difference between the general population and population with considering individuals with disabilities in terms of time to egress via an agent-based microsimulation called BUMMPEE model. This model can consider several types of disabilities explicitly in terms of speed, ability to negotiate the environment, and psychological profile depending on type of disability. The model was applied for a real four story office building. The results of simulation experiments show that there is a significant difference between mean evacuation time for homogenous and heterogeneous populations. An increase in population size leads to an increased difference. Additionally, results demonstrate that the fourth floor of the building has the worst performance among other floors and persons who use wheelchairs are most at risk during emergency evacuation process.
  Authors: Christensen, Keith; Sharifi, Mohammad Sadra; Chen, Anthony
  Authors: Christensen, Keith; Sharifi, Mohammad Sadra; Chen, Anthony
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-2790
• Particle Filter-Based Strategy for Online Calibration and Parameter Estimation of Motorway Traffic Model
  Abstract: This paper deals with a particle Bayesian filter framework for real-time motorway traffic state and online model parameters estimation, which can be useful for highway network monitoring and proactive traffic management and control applications. Due to the high nonlinearity of the traffic dynamics, Monte Carlo Bayesian approach is applied in combination with the transmission cell first order macroscopic traffic model. The implementation of this methodology demonstrates its ability to estimate, in real-time, the motorway traffic conditions together with the online estimation of model parameters. The validation is based on both simulated and real-world data.
  Authors: Sau, Jacques; El Faouzi, Nour-Eddin; Billot, Romain; Canaud, Matthieu
  Authors: Sau, Jacques; El Faouzi, Nour-Eddin; Billot, Romain; Canaud, Matthieu
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-2797
• Improving Automatic Vehicle Detection in Airborne Video Image Sequences
  Abstract: Data on vehicle movements can be used to derive parameters for microscopic traffic flow models and calibrate traffic simulation models. A software tool called Tracking and Registration of Airborne Video Image Sequences (TRAVIS) has been developed to extract vehicle positions from airborne imagery to assist in analyzing microscopic traffic behaviors. One of the critical challenges in analyzing airborne image sequences is the detection of vehicles and continued tracking of the vehicles through the sequence. The proposed technique includes several enhancements to TRAVIS to improve the vehicle detection and tracking. Firstly, a lower threshold is used in a difference image, allowing for detection of pixels with lower contrast to the background. This step is critical to picking up vehicles with little contrast with the road color (RGB intensity). Secondly, different techniques are used to threshold the red pixels, normal pixels and the pixels with lower contrast to the background, based on: (1) the pixel intensities in the original image; (2) the pixel intensities in the differenced image; and, (3) the relative positions of vehicles on the roadway. Thirdly, the dilation step is removed to avoid merging the vehicles very near each other. Fourthly, two blobs belonging to one vehicle are merged when labeling the connected components. Finally, non-vehicle and stationary blobs are screened out. Experimental results show that the number of vehicles detected and tracked is significantly increased, compared to the previous method.
  Authors: Du, Xueyan; Hickman, Mark D.
  Authors: Du, Xueyan; Hickman, Mark D.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-2738
• Modeling Microscopic Freeway Traffic Using Cusp Catastrophe Theory
  Abstract: This paper proposes a framework based on stochastic cusp catastrophe theory to model microscopic freeway traffic flow. The approach considers that each driver - regardless of being aggressive or timid - may shift his/her behavior and behave aggressively or timidly during driving. Based on the proposed modeling approach, the spacing a driver choses is a function of its speed and acceleration. Moreover, the driver’s behavior encompasses two equilibrium states -being aggressive or timid - and any shift between these states is considered to occur as a catastrophe phenomenon. Different models are developed with variable sampling interval, while some of them encompass memory properties. Results show that the cusp catastrophe model may accurately describe microscopic traffic, especially when compared to linear or logistic models. Results for models with induced memory are even more promising. Considering the proposed method, preliminary results on the critical regions of breakdown conditions or attitude shifting are described and discussed.
  Authors: Papacharalampous, Alexandros Evangelos; Vlahogianni, Eleni I.
  Authors: Papacharalampous, Alexandros Evangelos; Vlahogianni, Eleni I.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2755
• Sensitivity Analysis of VISSIM Driver Behavior Parameters on Safety of Simulated Vehicles and Their Interaction with Operations of Simulated Traffic
  Abstract: Microscopic traffic simulation models, VISSIM in particular, have been continuously used in assessing operational performance of traffic networks. Recently, their application for safety assessment has also been mounting. However, modelers are practically left without any guidance on the impact of VISSIM parameter values for car-following and lane-changing models on safety of the simulated vehicles (aggressiveness or defensiveness) and their interaction with the operational aspect of the simulated traffic. This paper provides quantitative evaluation on the impact of these parameters by means of a sensitivity analysis on total of 21 driver behavior parameters of VISSIM (10 for car-following and 11 for lane-changing models). For the safety analysis, Surrogate Safety Assessment Model (SSAM) is used to detect the change in frequency of the simulated vehicle conflicts and the change in travel time is used to evaluate the impact on operational aspect of the simulation. The results identified that the most influential parameters for safety of the simulated vehicles are CC1 (Headway Time), CC2 (Following Variation), CC3 (Threshold for Entering ‘Following’) as well as CC4 and CC5 (‘Following’ Threshold) for the car-following model; ‘Safety distance reduction factor’ for free lane-changing model; ‘Lane changing position’ and ‘Maximum deceleration of trailing vehicles’ for necessary lane-changing model. The majority of these parameters are also found to interact with travel time of the simulation. It is concluded that parameter values have a significant impact on aggressiveness or defensiveness of the simulated vehicles and accordingly impact the safety and operations of the simulated traffic. Thus, common calibration process requires cautious examination on the way the simulated vehicles behave and it is important to balance the value of parameters that improve network performance but deteriorate the safety of the simulated vehicles or vice versa.
  Authors: Habtemichael, Filmon; Picado-Santos, Luis Guilherme
  Authors: Habtemichael, Filmon; Picado-Santos, Luis Guilherme
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 398
  Paper Number: 13-2767
• Assessing Redundancy of Freight Transportation Networks
  Abstract: Freight transportation network is an essential backbone for supporting the industrial activities and economic developments of the nation and global trade. In this paper, we develop a quantitative approach for assessing the redundancy of freight transportation networks, one of the four “Rs” (Robustness, Redundancy, Resourcefulness, and Rapidity) for calculating the resiliency triangle. Redundancy is characterized by two main dimensions: route diversity and network spare capacity. The route diversity dimension is to evaluate the existence of multiple efficient routes available for users or the degree of connections between a specific origin-destination (O-D) pair. The network spare capacity dimension is used to quantify the network-wide spare capacity with an explicit consideration of congestion effect. These two dimensions can complement each other by providing a two-dimensional characterization of freight transportation network redundancy. The case study of Utah statewide freight transportation network is provided to demonstrate the features of the two-dimensional approach as well as the applicability of the evaluation methodology.
  Authors: Jansuwan, Sarawut; Chen, Anthony; Xu, Xiangdong; Yang, Chao
  Authors: Jansuwan, Sarawut; Chen, Anthony; Xu, Xiangdong; Yang, Chao
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-2798
• Enhancing Roundabout Operations via Vehicle Connectivity
  Abstract: With in-vehicle automation and vehicle connectivity gaining momentum, Cooperative Adaptive Cruise Control (CACC) systems are expected to enter the market in the near future. Given that the number of roundabouts in the US has increased significantly, this research effort investigates the potential benefits of optimizing vehicle trajectories approaching a single-lane roundabout using CACC systems and vehicle to infrastructure connectivity. The optimization ensures that vehicles can enter the roundabout when gaps in the circulating roadway are available. The system is tested on a single-lane roundabout for different traffic demand and CACC market penetration levels. The study demonstrates that CACC systems could produce savings of up to 80 and 40 percent in total delay and fuel consumption levels, respectively relative to traditional roundabout control. Further benefits are also achievable if one considers the potential for reducing the time headway between CACC-equipped vehicles and thus increasing the lane capacity.
  Authors: Zohdy, Ismail; Rakha, Hesham
  Authors: Zohdy, Ismail; Rakha, Hesham
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 674
  Paper Number: 13-2809
• Hybrid Approach for Clustering Vehicle Classification Data to Support Regional Implementation of Mechanistic-Empirical Pavement Design Guide
  Abstract: This paper develops a hybrid approach for analyzing vehicle classification data and applies the approach to a fused dataset from multiple jurisdictions in the Canadian Prairie Region. Application of the approach results in a set of regional default truck traffic classification groups (TTCGs) for use in the Mechanistic Empirical Pavement Design Guide (MEPDG). The hybrid approach is a conglomeration of three components: statistical clustering procedures, engineering judgment, and industry intelligence. By applying the hybrid approach, analysts receive the joint benefits of analytical rigor and industry-oriented pragmatism. Application of this approach results in eight TTCGs for the Canadian Prairie Region, which exhibit distinct differences from the default distributions developed for national use in the United States.The benefits of the hybrid approach on fused datasets include: (a) the statistical strength gained from utilizing additional classification data, (b) the development of TTCGs that better reflect the diversity of patterns in the Region, and (c) the potential for improved ability to capture future shifts in truck traffic characteristics based on experience gained in other jurisdictions. The study also identifies limitations to the hybrid approach that should be considered. These limitations include varying data quality between jurisdictions, the sensitivity of low-volume sites to changes in industry patterns and the ability to track these changes, and a shortage of continuous classification sites in the Region. With a clear understanding of its benefits and limitations, the hybrid approach can be applied to truck traffic data analyses in any jurisdiction.
  Authors: Reimer, Mark Jonathon; Regehr, Jonathan D.
  Authors: Reimer, Mark Jonathon; Regehr, Jonathan D.
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management
  Session: 796
  Paper Number: 13-2849
• Quantifying and Comparing Left-Turn Strategy Performance
  Abstract: Intersection performance is often impacted and even limited by the need to serve left turn movements. Left turns may be served in a number of ways, varying from permitted left turns to flashing yellow left turn arrow to protected left turns. Each method may be employed in a number of different strategies. For example, protected left turns may be employed in leading left turns, leading and lagging left turns, conditional left turn phase reservice, and fixed left turn phase reservice.To give practitioners and researchers more insight into left turn operations, this research implements a number of different left turn strategies under varying volume, volume differential and turning conditions while measuring the delay and queue lengths associated with each left turn strategy. The following findings are discussed in this paper. First, at low volumes, permitted only phasing offers the best performance. Second, protective-permitted phasing, including leading left turn with green ball, Leading left turn with Flashing Yellow Arrow (FYA), and FYA followed by lagging lefts, performs better as volume differentials increase as well as when turning rates increase. Phase reservice on left turn phases has a definite impact on queue length and delay experienced by the left turn phase, though it is also likely to be accompanied by a decrease in performance elsewhere in the intersection.
  Authors: Corey, Jonathan; Lao, Yunteng; Wang, Yinhai
  Authors: Corey, Jonathan; Lao, Yunteng; Wang, Yinhai
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-2868
• Kinematic Wave Approach to Traffic Statics and Dynamics in a Double-Ring Network
  Abstract: Recently there has been much interest in understanding traffic dynamics in a double-ring network. In this study we propose a kinematic wave approach to analyzing and simulating traffic dynamics in a freeway double-ring network. We first define and solve the traffic statics problem for the network, from whose solutions we can derive a macroscopic fundamental diagram (MFD). We find that the flow-density relation in the MFD is not unique when one ring is congested. We then use a corresponding Cell Transmission Model to simulate traffic dynamics in the network with constant or random retaining ratios as well as traffic signals. Simulation results suggest that all stationary states in the MFD are stable and can be reached, but random retaining ratios drive the network to more symmetric traffic patterns and higher flow-rates, while traffic signals have the opposite effects. This study confirms that generally the flow-density relation is not unique in a freeway network and highlights the impacts of randomness and interruptions on network traffic flow. In the future we will be interested in further studying freeway and urban traffic within the framework of kinematic wave theories and discussing their differences in statics, dynamics, and other characteristics.
  Authors: Jin, Wen-Long; Gan, Qijian; Gayah, Vikash V.
  Authors: Jin, Wen-Long; Gan, Qijian; Gayah, Vikash V.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2870
• Validation of Macroscopic Lane-Changing Model
  Abstract: Systematic lane changes inside a weaving area could disrupt the whole traffic flow and, even lead to accidents. Recently, a macroscopic lane-changing model was proposed to model traffic dynamics inside the lane-changing area at a merging section. But this macroscopic lane-changing model hasn’t been validated with vehicle trajectory data. In this paper, we attempt to fill this gap. Lane changes are categorized into two types: left lane changes and right lane changes. Inside the lane-changing area, with the assumptions that traffic is fully balanced and all left lane changes are induced by on-ramp vehicles, two linear relations are derived: (i) the number of left lane changes within two adjacent lanes linearly increases from the leftmost lane to the shoulder lane; (ii) the total number of left lane changes is proportional to the flow-rate of on-ramp vehicles inside the lane-changing area. Detailed studies are presented for different time periods and road geometries by using NGSIM vehicle trajectory data. Validation results confirm that these two linear relations do exist. In addition, capacity reductions caused by the lane changes of weaving vehicles can be observed in the fundamental diagram of lane-changing traffic. This study helps to understand the macroscopic lane-changing traffic behaviors and sheds light on developing possible macroscopic lane-changing traffic flow models and ramp-metering and lane management strategies.
  Authors: Gan, Qijian; Jin, Wen-Long
  Authors: Gan, Qijian; Jin, Wen-Long
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 841
  Paper Number: 13-2866
• Life-Cycle Assessment of Cooperative Vehicle Infrastructure Systems
  Abstract: Life cycle assessment is a tool that quantifies the environmental impacts of products and processes. LCA has utilized in several fields, including transportation. This paper explains fundamentals of LCA and describes transportation applications, specifically, an LCA on a cooperative vehicle-infrastructure system. Cooperative vehicle-infrastructure systems (CVIS) are the basis of Connected Vehicles technology applications promising improvements in safety, mobility, and environmental impacts. Changing to a CVIS requires renovations; primarily, adding electronics and communications hardware to vehicles and infrastructure. Electronics manufacture has been challenged for high natural resources and energy demand. This creates concern over the potential environmental benefits or drawbacks of CVIS. Despite additional electronics, vehicle fuel savings yielded enough CO2 emissions and energy reductions to offset added electronics. Over a vehicle lifetime, drivers could save a net 71 metric-tons of CO2 emissions and reduce energy use by 106 gigajoules. This mass of sequestered CO2 would require planting over 2,500 trees.
  Authors: Park, Byungkyu (Brian); Malakorn, Kristin Jade
  Authors: Park, Byungkyu (Brian); Malakorn, Kristin Jade
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 674
  Paper Number: 13-2892
• Best Practices in Urban Freight Management: Lessons from an International Survey
  Abstract: Freight movement is essential to the function of metropolitan areas, yet it generates many externalities, including congestion, air pollution, noise, and Green House Gas emissions. Metropolitan areas around the world are seeking ways to manage urban freight and its impacts. This paper presents results from a comprehensive international survey of urban freight management strategies. Our purpose was to examine the effectiveness of alternative strategies and assess their transferability for broad US implementation. We use three categories to describe urban freight strategies: last mile/first mile deliveries and pickups, environmental mitigation, and trade node strategies. We find that there are many possibilities for better managing urban freight and its impacts including labeling and certification programs, incentive-based voluntary emissions reductions programs, local land use and parking policies, and more stringent national fuel efficiency and emissions standards for heavy duty trucks. More research is needed on intra-metropolitan freight movements and on the effectiveness of existing policies and strategies.
  Authors: Dablanc, Laetitia; Giuliano, Genevieve; Holliday, Kevin Thomas; O'Brien, Thomas Joseph
  Authors: Dablanc, Laetitia; Giuliano, Genevieve; Holliday, Kevin Thomas; O'Brien, Thomas Joseph
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Motor Carriers; Operations and Traffic Management
  Session: 709
  Paper Number: 13-2903
• 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
• The Language of Driving: Advantages and Applications of Symbolic Data Reduction for Naturalistic Driving Data Analysis
  Abstract: Recent advances in onboard vehicle data recording devices have created an abundance of naturalistic driving data. The amount of data exceeds the resources available to analyze it, forcing researchers to focus on analyses of "critical events," which are identified using simple heuristics. This critical event analysis eliminates the context that can be critical in understanding driver behavior, reducing the generalizability of the analysis. This work introduces a method of naturalistic driving data analysis that will allow researchers to examine entire datasets by reducing them by over 90%. The method utilizes a symbolic data reduction algorithm, Symbolic Aggregate approXimation (SAX), which reduces time-series data to a string of letters. SAX can be applied to any continuous measurement and SAX output can be reintegrated into a dataset to preserve categorical information. This work explores the application of SAX to speed and acceleration data from a naturalistic driving dataset and demonstrates SAX's integration with other methods that can begin to tame the complexity of naturalistic data.
  Authors: McDonald, Anthony D.; Lee, John D.; Aksan, Nazan S.; Dawson, Jeffrey; Tippin, Jon; Rizzo, Matthew
  Authors: McDonald, Anthony D.; Lee, John D.; Aksan, Nazan S.; Dawson, Jeffrey; Tippin, Jon; Rizzo, Matthew
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-2947
• Understanding Evacuation Destination Distance and Departure Time Choices: Joint Modeling Approach
  Abstract: This paper investigates the causal factors that influence the household-level evacuation departure timing and the destination distance choices under two different behavioral assumptions, namely the decisions are made simultaneously or sequentially with the evacuation timing determined after the destination. The effects of various independent variables are compared using the bivariate Generalized Linear Model (BGLM) and Poisson model. Under either assumption, the number of children under 17 and pre-evacuation preparation time are statistically significant. More children under 17 increase the likelihood of leaving early. Less time in pre-evacuation preparation leads to a later departure. The Poisson model with random parameters also found statistical significance for the household size and partial regional difference for evacuation timing choice. In the BGLM model, evacuation accommodation type, household income, and education level are statistically significant for evacuation timing. The travel distance depends on many factors. Public shelter as the destination, the number of elderly people, no evacuation warning, low income and shorter preparation time contribute to a shorter travel distance. A large household size, a mandatory evacuation recommendation, and post-graduate education level lead to longer travel distance. In order to examine the behavior of the households under the no-evacuation warning situation, a random-coefficient model is used to capture the possible behavioral heterogeneity among the underlying evacuation population under the sequential decision-making assumption. The departure time decisions for the “shadow evacuation” population are not statistically different from those who received an evacuation warning, but among the “shadow evacuation” population itself, departure timing shows heterogeneity.
  Authors: Yin, Weihao; Murray-Tuite, Pamela; Ukkusuri, Satish V.; Gladwin, Hugh
  Authors: Yin, Weihao; Murray-Tuite, Pamela; Ukkusuri, Satish V.; Gladwin, Hugh
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 671
  Paper Number: 13-2935
• Comparison of Sichel and Negative Binomial Models in Estimating Empirical Bayes Estimates
  Abstract: Traditionally, transportation safety analysts have used the empirical Bayes (EB) method to improve the estimate of the long-term mean of individual sites and to identify hotspots locations. The EB method combines two different sources of information: (1) the expected number of crashes estimated via crash prediction models, and (2) the observed number of crashes at individual sites. Crash prediction models have extensively been estimated using a negative binomial (NB) modeling framework due to the over-dispersion commonly found in crash data. Recent studies have shown that the Sichel (SI) distribution provides a promising avenue for developing crash prediction models. The objective of this study is to examine the application of the SI model in calculating EB estimates. To accomplish the objective of the study, the SI models with a fixed/varying dispersion term are developed using the crash data collected at 4-lane undivided rural highways in Texas. The important conclusions can be summarized as follows: (1) the selection of the crash prediction model (i.e., the SI or NB model) will affect the value of weight factor used for estimating the EB output; (2) the identification of hazardous sites, using the EB method, can be different when the SI model is used. Finally, a simulation study designed to examine which crash prediction model can better identify the hotspot is recommended as our future research.
  Authors: Zou, Yajie; Lord, Dominique; Zhang, Yunlong; Peng, Yichuan
  Authors: Zou, Yajie; Lord, Dominique; Zhang, Yunlong; Peng, Yichuan
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-2938
• Delay Estimation Under A Dynamic Speed Control-Based Intersection
  Abstract: Compared with traditional status, traffic stream under dynamic speed control has some different characteristics because of its distinctive communication mode, which are promoting a series of reviews toward current theories. This paper demonstrates how single and average vehicle delays are estimated under a dynamic speed control based intersection, with pre-timed signal control. Firstly, the research proposes a dynamic speed control algorithm based upon a car-following model under the Cooperative Vehicle Infrastructure Systems based environment. After that, we utilize the Kinematic theory and a recursive function to calculate delay of every single vehicle in a platoon. And then, an algorithm is advanced to estimate the average vehicle delay. It is found that the trajectory of a vehicle is dependent on the traffic status of the vehicle ahead. Once the traffic variables of the first vehicle are obtained, we can calculate average delay and single delay of all vehicles in a platoon. Finally, we give an example to validate the superiority under dynamic speed guidance than the traditional environment. It is clear that with the increase of proportion of intelligent vehicles, average delay under low volume has no obvious reduction. While over high volume, a significant decline is appeared. We also make a conclusion that proportion at 80% is most moderate, since average delay under which is nearly equal to the one under 100%.Key words: delay, dynamic speed control, intersection, Kinematic theory
  Authors: Chen, Wenqing; Bai, Yu; Yang, Xiaoguang
  Authors: Chen, Wenqing; Bai, Yu; Yang, Xiaoguang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2570
• Analytical Delay Model to Yielding Vehicles at Unsignalized Pedestrian Crossings
  Abstract: This paper describes a methodology for predicting the average delay to yielding vehicles at unsignalized crossings. It is assumed that vehicular headways are independent and have a dichotomized distribution, while the inter-arrival time of pedestrians follows an exponential distribution. The presented equations give an estimate of the expected vehicular delay as a function of the traffic volume, pedestrian volume and the vehicle yielding rate. Point-process based stochastic simulations were carried out to assess the validity of the model. The combined effects of varying degrees of traffic and pedestrian volume, as well as the yielding rate, are also discussed. The model can be applied for estimating the major-street through traffic delay with yielding effects in two-way stop-controlled intersections, which is a known limitation in Highway Capacity Manual 2010
  Authors: Wei, Dali; Liu, Hongchao; Kumfer, Wesley; Zong, Tian Z.; Yuan, Changwei
  Authors: Wei, Dali; Liu, Hongchao; Kumfer, Wesley; Zong, Tian Z.; Yuan, Changwei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2881
• Interaction Between Accessibility and Externalities When Optimizing Dynamic Traffic Management Measures on Network Level
  Abstract: Optimization of traffic network performance using dynamic traffic management (DTM) measures can be viewed as a specific example of solving a network design problem. Decision variables are the specific settings of DTM measures. DTM measures have been identified as not only powerful instruments to increase network efficiency, but also to improve externalities. As a result, in the optimization the focus is not only on efficiency, but also on climate, air quality, traffic safety and noise. These assessment criteria are determined using the output of a dynamic traffic assignment model. This results in a dynamic multi objective network design problem, which is solved as a bi-level optimization problem and results in a Pareto optimal set. The Pareto optimal set provides valuable information for the decision making process, which would not have been available if the compensation principle would have been chosen in advance. Knowledge obtained by optimization of realistic cases can also be used to attain knowledge about incorporation of externalities as an objective when optimizing traffic systems using DTM measures. In a case study for a realistic network of the city Almelo it is shown that the objectives efficiency, climate and air quality are mainly aligned and mainly opposed to traffic safety and noise. The objectives traffic safety and noise are neither aligned, nor opposed. However, this does not mean that there is a single solution which optimizes the three aligned objectives. Based on the Pareto optimal set the trade-offs are determined and using cluster analysis the solutions and results are further analyzed for network segments.
  Authors: Wismans, Luc J.J.; van Berkum, Eric; Bliemer, Michiel
  Authors: Wismans, Luc J.J.; van Berkum, Eric; Bliemer, Michiel
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2972
• No-Notice Evacuation Management: Ramp Closures Under Varying Budgets and Demand Scenarios
  Abstract: To promote smoother freeway traffic flow during evacuations, ramps may be closed, reducing the number of merging and related speed reduction points. Deciding which ramps to close can be treated as an optimization problem where the decision variables are integers indicating whether the ramp is open or closed. This paper examines the problem under multiple demand and budget scenarios for no-notice evacuations. Through the optimization formulation and solution method, optimized closure plans are developed for each scenario and compared to the “do-nothing” and an existing plan developed with professional judgment. The optimized plans outperform the others in terms of the evacuees’ total travel time but are sometimes associated with decreases in overall network throughput. Three ramp closures, consistent across the scenarios, are explored as a reduced closure plan and evacuee benefits are identified for all of the scenarios over the “do-nothing” option except in the most congested background traffic scenario. However, even in the most congested case, the 3-ramp closure plan improved evacuees’ travel times over the plan developed without analytical and simulation support. While the exact optimized ramp closure plan varies across scenarios and budgets, overlap of the plans can help generate a smaller closure plan that provides benefits over strictly judgment based plans and over the “do-nothing” option in less congested cases.
  Authors: Ghanipoor Machiani, Sahar; Murray-Tuite, Pamela; Jahangiri, Arash; Liu, Sirui; Park, Byungkyu (Brian); Chiu, Yi-Chang; Wolshon, Brian
  Authors: Ghanipoor Machiani, Sahar; Murray-Tuite, Pamela; Jahangiri, Arash; Liu, Sirui; Park, Byungkyu (Brian); Chiu, Yi-Chang; Wolshon, Brian
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors; Security and Emergencies
  Session: 514
  Paper Number: 13-3003
• Effect of Active Traffic Management on Travel Time Reliability: Case Study of I-5 in Seattle, Washington
  Abstract: The purpose of this study is to determine the impact that the installation of an Active Traffic Management (ATM) system has had on the travel time reliability of a seven-mile length of the I-5 corridor in Seattle, WA. The travel time reliability measures of planning time index and buffer index were used to evaluate the effectiveness of the I-5 ATM system. Using data collected from loop detectors along the highway segment, the travel time reliability of the northbound route was calculated for the period before and after the implementation of the ATM system in August 2010. Separate reliability indexes were calculated for each day of the week for each of the 19 detector locations along the route. The results of the study find an increase in the travel time reliability of the corridor after ATM system implementation. The system results in a higher level of travel time reliability during off-peak periods compared to the corridor without ATM.
  Authors: DeGaspari, Michael; Jin, Jing; Wall, William Jared; Walton, C. Michael
  Authors: DeGaspari, Michael; Jin, Jing; Wall, William Jared; Walton, C. Michael
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-3004
• Development and Testing of Priority Control System in Connected Vehicle Environment
  Abstract: Traffic signals provide service for multiple modes of travelers including vehicles, trucks, transit, pedestrians, bicycles, and emergency vehicles. Past research and experience have demonstrated the benefits of providing traffic signal priority for individual modes such as transit, emergency vehicles, and trucks. However, the priority treatment for each travel mode was addressed independently within the normal traffic signal operation. With the advancement of the wireless communication technologies, the global positioning system, and the development of the vehicle to vehicle (v2v) and vehicle to infrastructure (v2i) systems, called Connected Vehicles (CV), there is an opportunity to simultaneously identify and prioritize multiple vehicle requests for priority service. This paper addresses a decision framework for prioritizing requests for service from multiple modes within an integrated traffic signal control framework. The framework has been developed and tested using a microscopic hardware-in-the-loop simulation (HILS) environment based on VISSIM and field tested and demonstrated in a live network of six intersections in Anthem, Arizona. The successful demonstration shows that the potential for safer and more efficient multi-modal traffic signal operations is highly possible.
  Authors: Ding, Jun; He, Qing; Head, Larry; Saleem, Faisal; Wu, Wei
  Authors: Ding, Jun; He, Qing; Head, Larry; Saleem, Faisal; Wu, Wei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-3025
• Coordinated Optimization of Signal Timings for Intersection Approach with Pre-signals
  Abstract: Many congested intersections have heavy traffic volumes on movements where there is insufficient capacity due to geometric limitations. Installing pre-signals at midblock locations and reorganizing traffic upstream approach of an intersection is a promising and cost-effective method to address these capacity limitations. This paper focuses on developing and evaluating a coordinated optimization model for an isolated intersection approach with pre-signals to increase protected left turn phase capacity. The pre-signal model is based on two principles: (1) Explicitly capturing the interaction between the pre-signal signal and the main-signal by modeling the queuing process and capacity constraints of temporal and spatial limitations of the intersection; and (2) Optimizing the signal timings of both the pre-signal and the main-signal as well as the offset between them to produce the best operational strategy for the approach. The minimum green time required and the delay minimization problems are considered. Extensive experimental analysis has shown that the pre-signal model outperforms the conventional control method (without pre-signal). Sensitivity analysis of the signal timing method was also conducted to assist traffic engineers with selecting the appropriate length of the sorting area, phase sequence and early starting time of pre-signals. The results from this study offer a basis for traffic practitioners, researchers, and authorities to design and utilize pre-signals in situations where there is a need to increase intersection capacity for congested movements.
  Authors: Ma, Wanjing; Xie, Hanzhou; Liu, Yue; Head, Larry; Luo, Zhenke
  Authors: Ma, Wanjing; Xie, Hanzhou; Liu, Yue; Head, Larry; Luo, Zhenke
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-3033
• Full Bayes Methods for Road Safety Studies: Does Prior Specification Matter?
  Abstract: This paper investigates the effect of prior assumptions when applying Full Bayes (FB) methods in road safety analysis. The effect of prior choice is evaluated in the accuracy of model parameters, hotspot identification, goodness-of-fit, and treatment effectiveness index in before-after studies. Particular attention is devoted to conditions with lack of data referenced as the low-mean and small-sample problem. In this research, informative, semi-informative, and no-informative priors were determined based on past published studies. Using a simulation framework, various scenarios of sample size and crash occurrence mean are evaluated. Simulated data is generated based on two real databases of divided/undivided rural highway segments in New York and Texas. Diverse sample mean values were obtained considering different time periods (number of years) and classifying accidents in injury-fatal and total accidents. Among other results, it was found that under low-mean and small sample conditions, the outcomes can be significantly biased. However, the introduction of informative priors can still make feasible observational before-after studies when working with small number of observations from treatment and/or comparison sites. Informative priors can help provide more accurate estimates of the treatment effectiveness. Finally, in accordance with previous works, it was shown that the inverse dispersion parameter is significantly affected by prior specifications; nevertheless, regression parameters, goodness-of-fit, and hotspot identification are only slightly sensitive to prior choices.
  Authors: Miranda-Moreno, Luis Fernando; Heydari, Mohammad; Amador-Jimenez, Luis
  Authors: Miranda-Moreno, Luis Fernando; Heydari, Mohammad; Amador-Jimenez, Luis
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology; Operations and Traffic Management; Safety and Human Factors
  Session: 658
  Paper Number: 13-3042
• Optimal Dynamic Pricing for Parking Management with Occupancy Information
  Abstract: Downtown parking is a challenging issue for both travelers and transportation planners. The objective of this paper is to maximize the benefits of parking management by optimal pricing and sensing. A generic parking model is presented for a set of sequential parking lots. Provided with the real-time parking occupancy information pricing information, travelers make parking location choices to minimize their generalized travel cost. We consider a general parking searching time function with respect to the occupancy. When the time-varying travel demand is fixed, we show that the system optimum (SO) pricing solution is not unique. The non-uniqueness indeed offers much flexibility to set different dynamic pricing schemes for a variety of parking management goals. Two special parking management strategies are discussed here, flow proportionality and least-square minimum congestion. The model can be implemented in practice by utilizing parking sensors to set optimal on-line parking prices. It is found that the parking pricing and the provision of occupancy information jointly serve as effective ways of managing traffic.
  Authors: Qian, Zhen; Rajagopal, Ram
  Authors: Qian, Zhen; Rajagopal, Ram
  Year: 2013
  Document Type: Paper
  Subject: Finance; Operations and Traffic Management; Policy
  Session: 294
  Paper Number: 13-3049
• Cost-Estimate Model for Transportation Management Plan Strategies for Highway Construction Projects
  Abstract: Highway rehabilitation projects frequently cause road congestion and increase safety concerns while limiting access for road users. State Transportation Agencies (STAs) are challenged to find safer and more efficient ways to renew deteriorating roadways in urban areas. To better address the work zone issues, the Federal Highway Administration published updates to the Work Zone Safety and Mobility Rule in 2007. One of the rule¡¯s major elements is to develop and implement Transportation Management Plans (TMPs). TMP cost for a road project is generally considered a high-cost item and, therefore, must be quantified. However, no tools or systematic modeling methods are available to assist agency engineers with TMP cost estimating. The research in this paper included reviewing TMP reports for recent projects regarding TMP practices and inputs from the district TMP traffic engineers in the California Department of Transportation (Caltrans). The researchers collected Caltrans highway project data regarding TMP cost estimating. Then, using Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software, the researchers performed case studies and proposed a TMP strategy selection and cost estimate (STELCE) model for highway projects. The proposed model was validated through the actual highway projects in California. Although the proposed TMP STELCE model was developed based on Caltrans TMP practices, other STAs may adopt this model in their TMP processes after adequate adjustments reflecting their requirements. Finally, the authors recommended that a more detailed step-by-step TMP strategy selection and cost estimate process be included in the TMP guidelines to improve the accuracy of TMP cost estimates.
  Authors: Kim, Changmo; Lee, Eul-Bum; Pyeon, Jae-Ho; Ellis, Ralph D.; ShakerNia, Akbar
  Authors: Kim, Changmo; Lee, Eul-Bum; Pyeon, Jae-Ho; Ellis, Ralph D.; ShakerNia, Akbar
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 339
  Paper Number: 13-3098
• Selecting Speed Limits for Multilane Highways with Curbs and Gutters
  Abstract: Most states discouraged the use of curb on roadways with design or operating speed over 45 mph. The research herein is to assess current speed limit practices when widening two-lane highways with speed limits of 55 mph to multilane highways with curb and gutter cross-sections and to recommend, if appropriate, enhanced design standards and speed limit guidelines. The research included a number of related tasks. The speed studies at 32 sites, which had recently been upgraded from 2 lane roadways to 4 or 5 lane roadways with curb and gutter profiles was conducted. The speed variances and speeding rates at these sites were examined and compared to corresponding data from similar sites on two-lane roadways. A series of human factors studies, utilizing the state-of-the-art DS-600c driving simulator system at the University of Tennessee, was conducted to assess the effects of curb and gutter profiles and posted speed limits on driver speed selection. In addition, a study of the effects of speed limits, in combination with cross-sectional elements, on crash rates was performed utilizing crash data from the Highway Safety Information System (HSIS). Based on the collective research findings, it is recommended that traffic agencies develop an alternative design standard for use on ¡°transitional roadways¡± as defined in this research. The alternative standard would allow the use of design speeds and posted speed limits in excess of 45 mph, along with the use of appropriate sloping curbs, on this new category of roadways.
  Authors: Richards, Stephen H.; Dong, Chunjiao; Yang, Qiang; Jiang, Ximiao
  Authors: Richards, Stephen H.; Dong, Chunjiao; Yang, Qiang; Jiang, Ximiao
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 405
  Paper Number: 13-3105
• Build It and They Will Yield: Study of Motorist Yield Compliance and Pedestrian Delay at Marked Crosswalks on Multilane Roadway
  Abstract: The purpose of this report is to describe the interaction between motorists and pedestrians at various marked crosswalk locations along Cabrillo Boulevard, a multilane street in the Coastal Zone of Santa Barbara. Data on motorist yield compliance by lane, and observed pedestrian delay to cross are recorded in the presence of traffic, before and after the construction of pedestrian refuge islands and curb extensions. These data are assessed to describe the effectiveness of the treatment under actual field operational conditions. The measures of effectiveness include: crossing delay, number of motorists failing to yield, and distance drivers yield from the crosswalk.
  Authors: van Hengel, Drusilla
  Authors: van Hengel, Drusilla
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Pedestrians and Bicyclists; Deploying Transportation Research-Doing Things Smarter, Better, Faster
  Session: 700
  Paper Number: 13-3084
• Proactive Optimal Variable Speed Limit Control for Recurrent Congested Freeway Bottlenecks
  Abstract: The study presents two models for proactive VSL control on recurrently congested freeway segments. The proposed basic model uses embedded traffic flow relations to predict the evolution of congestion pattern over the projected time horizon and computes the optimal speed limit. To contend with the difficulty in capturing driver responses to VSL control, this study also proposes an advanced model that further adopts Kalman Filter to enhance the accuracy of traffic state prediction. Both models have been investigated with different traffic conditions and different control objectives. Our extensive simulation analysis with a VISSIM simulator, calibrated with field data from our previous VSL demonstration site, has revealed that both proactive VSL control models can significantly reduce the travel time and number of stops over the recurrent bottleneck locations, and the one with minimizing speed variance as its control objective clearly outperforms other models, with respect to several selected MOEs.
  Authors: Yang, Xianfeng; Lu, Yang (Carl); Chang, Gang-Len
  Authors: Yang, Xianfeng; Lu, Yang (Carl); Chang, Gang-Len
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 402
  Paper Number: 13-3139
• Long Queue Estimation Using Short Vehicle Trajectories for Signalized Intersections
  Abstract: Queue length is one of the key components in traffic monitoring and signal control at arterial intersections. For congested links, queues are difficult to measure or estimate from either loop detectors or mobile sensors, as they may exceed the region of detection. In this paper, a queue length estimation model is proposed to solve this long queue problem using short vehicle trajectories. We first introduce the vehicle trajectory reconstruction model to estimate the missing part in vehicle deceleration or acceleration. The long queue model is then reduced to an ordinary short queue model. A delay-based estimation method is developed to evaluate the cycle-by-cycle queue length. The proposed method is applicable to the moving queue or over-saturation condition, and performs well under low penetration rate. The model is tested in a field experiment with reasonable results.
  Authors: Hao, Peng; Ban, Xuegang (Jeff)
  Authors: Hao, Peng; Ban, Xuegang (Jeff)
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3178
• A Heterogeneous Visual Imaging Model for Analyzing Impact of Vehicle Type on Car-Following Dynamics
  Abstract: Heterogeneity is an essential characteristic in car-following behaviors, which can be defined as the differences between the car following behaviors of driver/vehicle combination under comparable conditions. This paper proposes a Visual Imaging Model (VIM) with relaxed assumption on a driver¡¯s perfect perception for 3-D traffic information and uniform reaction to vehicles with different sizes in most existing car following models. The proposed model can generate greater stimuli to the followers from the leading vehicles with larger back sizes (i.e. defined as vehicle width¡Ávehicle height) and short distance to the following vehicles, but less changes in stimuli for the distant leading vehicles under various back sizes. The US101 NGSIM data set containing vehicle type/size information is used to evaluate the proposed model at the levels of single trajectory pair and vehicle types. The calibration and validation results show the promising performance of the proposed model in describing heterogeneous car-following behavior. In this study, it is also found from US101 NGSIM data set that in relatively high velocity range, the following gap distance for car following truck (C-T) is greater than that for car following car (C-C), while in low velocity range, C-T has a smaller spacing than C-C. The phenomenon can also be reproduced by the proposed model.
  Authors: Zheng, Liang; Jin, Jing; Cheng, Yang; Ma, Shoufeng; Ran, Bin
  Authors: Zheng, Liang; Jin, Jing; Cheng, Yang; Ma, Shoufeng; Ran, Bin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3126
• Self-Organizing Traffic Signals Using Secondary Extension and Dynamic Coordination Rules
  Abstract: Actuated control is very efficient for isolated intersections, but along arterials it lacks the means to synchronize signals, leading to frequent stops. Industry practice in the United States is to use clock-based coordination for arterial control, with signals running with a common cycle and offsets that help ensure good progression. However, clock-based coordination has many drawbacks, among them increased delay for pedestrians, promoting speeding, and a low degree of flexibility for accommodating transit priority. This research proposes a new paradigm for traffic signal control, “self-organizing signals,” that begin with a base of actuated control, but with rules added that can lead signals to synchronize with their neighbors. Rules were developed for secondary extensions to serve an imminently arriving platoon and, for closely spaced intersections, dynamic coordination which forces signals to synchronize with a critical intersection. Simulation tests in two corridors indicate the success of this self-organizing logic, with delay reductions of up to 14% compared to an optimized coordinated-actuated scheme where there is no transit priority. With transit signal priority applied aggressively, transit delay was reduced by more than 10 seconds per train per intersection (more than 50% reduction in transit delay) with almost no impact to traffic.
  Authors: Cesme, Burak; Furth, Peter G.
  Authors: Cesme, Burak; Furth, Peter G.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3197
• Can Psychological Traits Help Predict the Use of Managed Lanes?
  Abstract: This research examined the impact of several personality traits (conscientiousness, general locus of control, personal need for structure, risk tolerance (financial), driving risk perceptions, risky driving style, and careful driving style) on survey respondents’ travel choices on managed lanes. To begin, the survey was pilot tested using a sample of 24 graduate and 231 undergraduate students at Texas A&M University. The pilot test confirmed internal consistency reliability of the psychological measures and demonstrated that the pattern of relationships between the constructs was consistent with their hypothesized associations. The survey was then administered online to travelers in San Diego, Miami, and Denver. Mode choice models were developed using the mixed logit modeling method based on the 664 respondents from the three cities. The models found that several variables, particularly travel time, toll, gender and income, were better predictors of ML usage than the psychological variables. However, a couple of psychological variables were significant in a couple of the models:•respondents with a higher risky driving style score were less likely to choose the carpooling on the GPLs. This seems reasonable since many of the risky driving style questions dealt with faster travel – which MLs allow. •respondents with high conscientiousness scores were less likely to choose carpooling on the GPLs. This seems reasonable as those with high conscientiousness liked structure and both carpooling and the GPLs were the least structured options.Therefore, this research found that some psychological variables have the expected relationships with a traveler’s mode choice. However, the impact was minimal based on the models developed here.
  Authors: Devarasetty, Prem Chand; Burris, Mark W.; Arthur, Winfred; McDonald, Jennifer; Munoz, Gonzalo
  Authors: Devarasetty, Prem Chand; Burris, Mark W.; Arthur, Winfred; McDonald, Jennifer; Munoz, Gonzalo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 775
  Paper Number: 13-3205
• Research on Dynamic Signal Control for Exclusive Right-Turn Lane at Mixed Traffic Flow Intersections
  Abstract: Traffic conflicts among right turn vehicle (RTV), non-motorized vehicle (NMV) and pedestrian were examined for urban signalized intersections with exclusive right turn lane. This study proposed an approach to dynamically calculating the duration of the prohibited right turn for vehicles by using a measure we call the Degree of Clustered Conflict, (DCC). The process of DCC control includes: 1) quantitatively calculating DCC value in conflict area; 2) establishing the general cost model that combines delay and conflict indicators; and 3) applying the DCC-control time model to control right turn vehicle in real time. Based on these, the paper presented a general approach of detailed dynamic on-line signal control process of RTV. Finally, the RTV control process was programmed based on VISSIM simulation to evaluate the control effectiveness. The results showed that the general cost (weighted summation of delay and conflict) of the RTV control decreases rapidly compared with non-control, fixed control and full control (drop 58%, 35% and 42% under small flow conditions and 70%, 59% and 17% in the large flow conditions, respectively). The method not only improved the operation efficiency, but also reduced the conflicts among traffic participants when vehicles turn right at intersections.
  Authors: Sun, Jian; Zhao, Li; zhang, Yancong; Wu, Zhizhou
  Authors: Sun, Jian; Zhao, Li; zhang, Yancong; Wu, Zhizhou
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-3206
• Self-Organizing Control Logic for Oversaturated Arterials
  Abstract: Decentralized, actuated traffic signal control has many advantages, but lacks mechanisms for coordinating with other signals along an arterial. When an intersection along an arterial is near or over saturation, coordination can play an important role in preserving and utilizing capacity by preventing spillback and starvation. In this paper, rules that can be added to a base of decentralized, clock-free actuated control are proposed for managing queues during periods of oversaturation. They are part of a larger framework for developing logic that will make arterial traffic signals self-organizing, rather than organized around a common signal cycle. Features of the proposed logic include green truncation in case of intersection spillback, early green and double realization for left turn phases prone to pocket spillback due to a limited turn bay length, and dynamic coordination for groups of signals spaced too closely together to hold a normal cycle’s queue. With dynamic coordination, green waves are scheduled each cycle following the critical intersection’s critical arterial through phase, with non-critical intersections adjusting offsets based on queue counts and a logic that allows temporary spillback at upstream intersections in order to prevent starvation at the critical intersection, and temporary starvation at downstream intersections in order to prevent spillback at the critical intersection. Simulation tests using a benchmark network shows performance far superior to standard coordinated control, and slightly better than an optimizing control method designed for oversaturated arterials. Simulation tests on two realistic networks also show positive results compared to coordinated control.  
  Authors: Cesme, Burak; Furth, Peter G.
  Authors: Cesme, Burak; Furth, Peter G.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-3218
• Dynamic Lane-Based Signal Merge Control Model for Freeway Work Zone Operations
  Abstract: Traditional merge control strategies cannot yield expected effectiveness under heavy traffic conditions at freeway work zones because inevitable traffic conflicts resulted from complex merging and lane-changing maneuvers could increase the potential of traffic accidents, induce stop-and-go movements, and degrade the operational efficiency. This paper presents a dynamic control model to optimize the signal operations of a new merge system, the lane-based signal merge (LBSM), which uses lane-based signals or variable signs to give drivers in different lanes the right of way to proceed through the open lane(s) in a work zone area. The control objective is to maximize the work zone throughput. Genetic algorithm is employed to solve the model. Results reveal that the proposed method yields promising work zone operational performance under heavy traffic conditions.
  Authors: Liu, Yue; Mao, Jing; Yu, Jie
  Authors: Liu, Yue; Mao, Jing; Yu, Jie
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 339
  Paper Number: 13-3219
• Safety Distance Modeling on the Basis of Vehicle-to-Vehicle Communication
  Abstract: Safety distance modeling is one of the most important topics in collision prevention analysis. This paper presents an improved Safety Distance Model (SDM) based on the development of vehicle-to-vehicle communication technology. The technology enables on-time data collection as well as the real-time inter-vehicle communication. A tube-like highway scenario where vehicles enter at one end and exit at another is presented for demonstrating the application of the safety distance model. By incorporating both braking theory and driver behavior prediction model, the absolute and relative SDMs are developed to provide decision-making information to drivers in response to changing traffic conditions. The comparative analysis with four tradition SDMs confirmed that the proposed model describing the characteristics of vehicle-to-vehicle communication is able to improve the efficiency of vehicle collision prevention system, increase road utilization as well as ensure driving safety.
  Authors: Quan, Wei; Wang, Hua; Wang, Yinhai; Liu, Xiaoyue (Cathy)
  Authors: Quan, Wei; Wang, Hua; Wang, Yinhai; Liu, Xiaoyue (Cathy)
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-3222
• Reinforcement Learning-Based Signal Control Using R-Markov Average Reward Technique Accounting for Neighborhood Congestion Information Sharing
  Abstract: This research proposes and implements a reinforcement learning (RL) based signal control using R-Markov Average Reward Technique (RMART) accounting for neighborhood congestion information sharing. The algorithm is implemented and tested at network level in a traffic simulation tool (VISSIM) using the COM interface. The comparison with traditional Q-learning and SARSA algorithms indicate that RMART performs better at higher congestion level. Different reward functions are tested with the algorithms at different congestion level. Further, a multi-reward structure for RL is proposed that dynamically adjusts the reward with varying congestion state at the intersection.
  Authors: Aziz, H. M. Abdul; Ukkusuri, Satish V.; Feng, Zhu
  Authors: Aziz, H. M. Abdul; Ukkusuri, Satish V.; Feng, Zhu
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3227
• Vehicle Classification Approach Based on Wavelet K-Nearest Neighbor Using Inductive Loop Signatures
  Abstract: In this study, a new vehicle classification algorithm was developed using the inductive loop signature technology. There were two steps of the proposed algorithm. The first step was to utilize the Haar wavelet to transform and reconstruct inductive vehicle signatures, and the second step was to group vehicles into Federal Highway Administration (FHWA) vehicle types using the K-Nearest Neighbor (KNN) approach with Euclidean distance classifier. To determine the proper proportion of the wavelet to be applied for reconstruction and feature extraction, transformed signatures were examined with different percentages of large components of their corresponding wavelets. To implement KNN, a library of vehicle signature templates for each FHWA vehicle class was composed. The proposed vehicle classification algorithm demonstrated promising classification results with a 92.4% overall accuracy, and it can be applied to the real-world without the concerns of re-calibration and transferability using signature data from single loops. Two additional vehicle classification schemes were applied for performance evaluation. For the ISPE (Inductive Signature Performance Evaluation) classification scheme, which aimed to facilitate emission analysis and easy interpretation, the overall accuracy was 94.1%. For the axle-based vehicle classification scheme proposed in this project, which aimed to group vehicles via usage and the number of axles of the vehicles, the overall accuracy was 93.8%. Future research will focus on refining the signature template library for each FHWA vehicle type to further improve the performance of the proposed vehicle classification algorithm. The selection of the value of k for the KNN approach will also be investigated.
  Authors: Jeng, Shin-Ting (Cindy); Chu, Lianyu; Hernandez, Sarah Vavrik
  Authors: Jeng, Shin-Ting (Cindy); Chu, Lianyu; Hernandez, Sarah Vavrik
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 668
  Paper Number: 13-3182
• Signal Timing Optimization Based on Platoon Segmentation by Using High-Precision Microwave Data
  Abstract: With the development of modern information, communication and connected-vehicle technologies, it is possible to further improve the traffic signal control by using real-time, accurate, and large-scale traffic information. This paper puts forward a new signal timing optimization method based on platoon segmentation by using the high-precision microwave data. An intersection located in the Albany, California is studied as a target intersection. Three microwave sensors are deployed in this intersection which can collect the information of all the moving vehicles in this area every 50 milliseconds. This paper presents the method of platoon segmentation, performance measurement of control delay, control strategies (including green extension, phase termination and double cycle), delay estimation and several application scenarios in detail. Furthermore, by using the actual microwave data and the proposed methods, the paper illustrates the probability density functions of delayed through vehicles, startup and queuing delay etc. Finally, the paper provides the comparative results of control delay by implementing the in-used and proposed three signal timing strategies, which can prove the feasibility and effectiveness of the proposed method.
  Authors: Zhang, Jiajie; Hu, Jianming; Zhou, Kun; Zhang, Wei-Bin
  Authors: Zhang, Jiajie; Hu, Jianming; Zhou, Kun; Zhang, Wei-Bin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3193
• Multistage System for Planning Analysis and Signal Design of Diverging Diamond Interchange
  Abstract: As one of the most popular unconventional interchange designs, diverging diamond intersection (DDI) has received increasing attention over the past decade. This study, responding to the needs, has produced a reliable and convenient system for traffic engineers to perform operational analysis of DDI. The entire system comprises three modules for planning analysis, signal optimization, and operational evaluation. At the planning stage, this system presents a set of empirical equations for engineers to compute the overall interchange delay and identify the potential queue spillback locations in a DDI design. The second module aims to provide the optimal signal plans to prevent the potential queue blockage. This module is unique in its consideration of the interdependent relations between queues at a DDI¡¯s closely-spaced intersections, and the impacts by both geometrical constraints and traffic volumes. Given the traffic volumes, geometrical features, and signal timings, the system¡¯s third module provides users to link a VISSIM-based simulation model to estimate the resulting traffic queues and interchange delays. Numerical analysis with four real-world DDI designs has revealed the effectiveness of the proposed system.
  Authors: Yang, Xianfeng; Chang, Gang-Len; Rahwanji, Saed
  Authors: Yang, Xianfeng; Chang, Gang-Len; Rahwanji, Saed
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-3245
• An Empirical Assessment of Interactions Between Bus Rapid Transit and General Traffic Flows
  Abstract: Bus rapid transit (BRT) is a high-capacity urban public transit system with exclusive right-of-way. It is important to evaluate the interactions between BRT and general traffic flows. An empirical assessment framework is proposed to investigate traffic congestion and lane-changing patterns at one typical bottleneck along a BRT corridor by using the well-developed oblique cumulative vehicle counts (CVC) and lane changes. We extend the method that was widely applied in freeway bottleneck analyses to urban BRT corridors. The bottleneck consists of BRT bus lane, BRT station, video enforcement zone and transit signal priority (TSP) intersection. In the study site, we assume four lane-changing patterns, three of which are directly verified by the empirical measurements. We explore violating influences on both general traffic and buses. Results show that lane violations induce 16% saturation rate reduction of general traffic and 17% increase in bus travel time. Further investigations show that the BRT station and its induced increasing lane-changing maneuvers are observed to increase the downstream queue discharge flows of general traffic. The empirical results also contribute to more efficient strategies of BRT planning and operations, such as alternative enforcement methods, various lane separation types, and optimized traffic operations.Keywords: BRT; lane violations; cumulative vehicle counts (CVC); enforcement camera
  Authors: Chen, Xiqun (Michael); Li, Meng; Jiang, Han; Li, Zhiheng
  Authors: Chen, Xiqun (Michael); Li, Meng; Jiang, Han; Li, Zhiheng
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 807
  Paper Number: 13-3261
• Gaussian Model of Macroscopic Traffic Flow: Derivation, Analysis, and Validation
  Abstract: This paper derives a second order Gaussian approximation of a queueing model of traffic flow. The derived Gaussian model is fully characterized by deterministic time varying mean and covariance dynamics, which are simple to compute. Time varying covariance matrices are computed using only parameters of the fundamental diagram, while also capturing dependency between traffic variables in adjacent cells. The proposed approximation, thus, serves as an analytically tractable stochastic model for purposes of real-time estimation and prediction of traffic conditions along both freeways and signalized arterials. Namely, the model is linear in the stochastic traffic variables, which allows for use of a standard Kalman filter of the continuous-discrete type. Stationarity properties of the covariance matrices are discussed and their bounded behavior is demonstrated via numerical examples. A preliminary validation of the proposed model is carried out using high-resolution traffic data in a real-world traffic state estimation example, in which a good agreement between estimated traffic states and observed traffic states was found.
  Authors: Jabari, Saif Eddin; Liu, Henry X.
  Authors: Jabari, Saif Eddin; Liu, Henry X.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3262
• Application of Pavement Marker to Avoid Queue-jumping and Traffic Spillback at Off-ramp of Expressways
  Abstract: Urban expressways are connected tightly to local surface/arterial roads through off-ramps and due to the increased traffic volume during peak hour, traffic flows near off-ramps are usually chaotic and difficult to manage. Therefore better understanding of traffic flow behavior at off-ramps is critical to improve traffic management of urban expressways. Drivers¡¯ queue-jump behavior near the off-ramp occurs frequently in developing countries, which contributes significantly to the traffic flow complexity. However, queue-jump behavior is often ignored in the existing microscopic traffic simulation packages. In this paper, we develop cellular automata based simulation model, which specifically targets on the traffic spillback and queue jump behaviors near expressway off-ramp. Queue-jump rules are incorporated into the car-following and lane changing logics of the cellular automata model. Using the developed model, we simulate different configurations of pavement markings around off-ramp in combination with different off-ramp signal timings. The results show that, although solid pavement markers is designed to reduce the number of discretionary lane-changes, when off-ramp signal cycle is short, the total off-ramp delay is increased, comparing with that of dashed pavement marker. We also show that, breaking FIFO queuing (i.e. queue-jump is allowed) will improve the freeway efficiency, which confirms Daganzo¡¯s argument on the damaging effect of FIFO queuing (Daganzo, et al. 2002).
  Authors: Zhang, Xiaoning; Di, Xuan; Zhang, H. Michael; Liu, Henry X.
  Authors: Zhang, Xiaoning; Di, Xuan; Zhang, H. Michael; Liu, Henry X.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3298
• 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
• Asymptotic Stability of Boundedly Rational Day-to-Day Dynamic
  Abstract: Although the bounded rationality day-to-day dynamic proposed in \cite{guo2011bounded} managed to model drivers' transient behaviour under disequilibrium, its stability property remains unanswered. To better understand the bounded rational (BR) dynamic, this paper initiates the stability analysis of the BR dynamic on a toy network. As we will show, the BR dynamic is a piecewise affine linear system consisting of multiple subsystems, thus the conventional Lyapunov theorem commonly used in the literature cannot be applied here. However, three methods: Multiple Lyapunov Function, Piecewise Quadratic Lyapunov Function and Commuting stability method are able to be tailored to deal with the stability of a piecewise affine linear system. Three methods will be implemented to a toy network to illustrate how the stability analysis of the BR dynamic can be conducted, which will help us better understand the BR dynamic and facilitate the future application to the BR dynamic, such as dynamic congestion pricing.
  Authors: Di, Xuan; Liu, Henry X.; Pang, Jong-Shi; Ban, Xuegang (Jeff)
  Authors: Di, Xuan; Liu, Henry X.; Pang, Jong-Shi; Ban, Xuegang (Jeff)
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3287
• New Methodology for Systemwide Intersection Signal Timing Optimization Simultaneously Minimizing Vehicle and Pedestrian Delays
  Abstract: This study introduces a new methodology for systemwide intersection signal timing optimization that is carried out by adjusting green, yellow, and red splits for all signalized intersections in the network for AM peak, PM peak, and rest of the day periods without changing the cycle length and signal coordination to achieve the lowest level of vehicle and pedestrian delays per cycle over a 24-hour period. The proposed methodology contains a basic model that handles vehicle delays only and an enhanced model that simultaneously deals with vehicle and pedestrian delays, respectively. Both models are incorporated into a simulation-based model that could conduct regional traffic assignments on a second-by-second basis and applied using data on Chicago regional travel demand, field vehicular and pedestrian traffic counts, geometric designs, and traffic control particularly traffic signal timing plans for intersections in Chicago Central Business District (CBD) street network. The computational experiment reveals that vehicle delay reductions in Chicago CBD could reach 10 percent by minimizing vehicle delays only for signal optimization and 3-5 percent by jointly minimizing vehicle and pedestrian delays for signal optimization. The computational results could be further related to specific traffic signal coordination strategies for different study areas to determine desirable changes in field deployed cycle lengths, splits, and coordination to reduce delays and congestion.
  Authors: Roshandeh, Arash M.; Levinson, Herbert S.; Li, Zongzhi; Patel, Harshingar; Zhou, Bei
  Authors: Roshandeh, Arash M.; Levinson, Herbert S.; Li, Zongzhi; Patel, Harshingar; Zhou, Bei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3391
• Evaluation of Microwave Radar Vehicle Detectors at Signalized Intersection Under Adverse Weather Conditions
  Abstract: Two microwave-based systems for vehicle detection, manufactured by Wavetronix and MS SEDCO, were evaluated at stop bar and advance zones of a signalized intersection under three adverse weather conditions: 1) high wind speeds, 2) rain, and 3) fully/partially snow-covered roadway. Data under normal (favorable) weather was also analyzed and used for comparison. Results show that the performance of the two systems deteriorated during adverse weather, and the type of detection errors and their frequency were system-dependent. In general, wind increased false calls at the advance detection zone by more than 50%, depending on the location and sensor type; snow-covered roadway had more widespread effects and increased false calls at stop bar and advance zones, depending on the system, and also increased missed calls at stop bar zones; and lastly, rain also affected the two systems by increasing false calls and stuck-on calls at the stop bar, and false calls at the advance zones. Data also shows that frequencies of false and missed calls were likely to increase as the precipitation intensity and wind speeds increased. Results from this evaluation show significant effects of adverse weather on microwave detection systems, and provide valuable information to researchers and practitioners regarding performance of similar setups under such conditions. Details on the detection errors offer insight on potential situations that should be monitored in practice and could also be used to improve performance under adverse weather.
  Authors: Medina, Juan C.; Ramezani, Hani; Benekohal, Rahim F.
  Authors: Medina, Juan C.; Ramezani, Hani; Benekohal, Rahim F.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 541
  Paper Number: 13-3394
• Arterial Traffic Signal Optimization: A Person-Based Approach
  Abstract: This paper presents a traffic responsive signal control system that optimizes signal settings based on minimization of person delay on arterials. The system's underlying mixed integer linear program minimizes person delay by explicitly accounting for the passenger occupancy of autos and transit vehicles. This way it can provide signal priority to transit vehicles in an efficient way even when they travel in conflicting directions.Furthermore, it recognizes the importance of schedule adherence for reliable transit operations and accounts for it by assigning an additional weighting factor on transit delays. This introduces another criterion for resolving the issue of assigning priority to conflicting transit routes. At the same time, the system maintains auto vehicle progression by introducing the appropriate delays for when interruptions of platoons occur. In addition to the fact that it utilizes readily available technologies to obtain the input for the optimization, the system's feasibility in real-world settings is enhanced by its low computation time. The proposed signal control system was tested on a segment of San Pablo Avenue arterial located in Berkeley, California. The findings have shown the system's capability to outperform static optimal signal settings and have demonstrated its success in reducing person delay for bus and in some cases even auto users.
  Authors: Christofa, Eleni; Aboudolas, Konstantinos; Skabardonis, Alexander
  Authors: Christofa, Eleni; Aboudolas, Konstantinos; Skabardonis, Alexander
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 261
  Paper Number: 13-3395
• Volume-to-Capacity Estimation of Signalized Road Networks for Metropolitan Transportation Planning
  Abstract: Transportation planning has been playing a critical role in shaping economic health and quality of life. It not only provides insight into the mobility of people and goods, but also influences patterns of growth and economic activity. Metropolitan transportation planning is a challenging transportation topic because of the lack of future traffic information, like evaluating the capacity sufficiency on a large metropolitan road network with signalized intersections. The Highway Capacity Manual provides methods for analysis of signalized intersections and urban streets for planning. However, these methods need detailed traffic volume inputs and lane configurations at signalized intersections, which are normally not readily available in metropolitan transportation planning. The conventional four-step planning process is widely used to forecast directional traffic volumes on each road segment, but the projected volumes are not enough for analyzing capacity sufficiency of future road networks by existing methods. In this study, a simplified v/c ratio estimation procedure was developed based on available planning data and characteristics of signalized intersections. It links traffic assignment results of the conventional transportation planning procedure and capacity sufficiency estimation. By using the proposed method, transportation planners can estimate capacity sufficiency of future metropolitan road networks with available data in transportation planning. It will dramatically decrease the effort required for capacity evaluation of large metropolitan road networks.
  Authors: Xu, Hao; Liu, Hongchao; Fernando, Hiron; Senadheera, Sanjaya P.
  Authors: Xu, Hao; Liu, Hongchao; Fernando, Hiron; Senadheera, Sanjaya P.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 403
  Paper Number: 13-3410
• Effect of Surrounding Traffic Characteristics on Lateral Movement Behavior in Heterogeneous Traffic Conditions
  Abstract: Lateral movements in heterogeneous traffic streams have a significant impact on the characteristics of traffic flow. Lateral movement models, therefore form an important component of mixed traffic micro-simulation tools. Lateral movement maneuvers can be divided into three sequential stages: the motivation to change the current path, the selection of a path (either to the left or right) to change into and the execution of the lateral movement. The first two stages constitute the lateral movement decision and the final stage is associated with the lateral movement performance. Existing lateral movement models emphasize the general car-based decision-making aspects of the task, but generally neglect the detailed modelling of the tactical decisions and execution by vehicle type. The absence of mode-based lateral shift models in the current simulation tools may have a significant impact on simulated traffic flow characteristics and on simulation outputs. This paper analyses the effect of surrounding traffic characteristics on lateral movements of each vehicle type with respect to their tactical decisions and choice making. The analysis is carried out using detailed vehicle trajectory data that was collected in mixed traffic driving conditions using high mounted video cameras. For extracting the trajectories of vehicles, a vanishing-point based camera calibration technique which converts the image coordinates to real world coordinates was made use of. The rigorous statistical tests conducted for the similarity of mode-specific influential variables clearly indicate the existence of significant difference between them giving rise to the need for development of vehicle type dependant models.
  Authors: Munigety, Caleb Ronald; Mantri, Sruthi; Mathew, Tom V.; Rao, Krishna
  Authors: Munigety, Caleb Ronald; Mantri, Sruthi; Mathew, Tom V.; Rao, Krishna
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3525
• Estimation of Warehouse Throughput in a Freight Transport Demand Model for the Netherlands
  Abstract: This paper presents an extension of the classical 4-step freight modeling framework with a logistics chain model. Modeling logistics at the regional level is important because it establishes a link between trade flow and transport flow, allows determination of the warehouse and distribution centers locations and throughput volumes, and permits more detailed and accurate policy decision support systems. This paper describes a two-stage logistics model that estimates the volumes of regional warehouse throughput. The first stage estimates interregional trade flows by means of a gravity model application starting from regional production and consumption volumes. The second stage, the logistics chain model, splits the production-consumption flow between direct shipments and shipments via warehousing facilities. We use an aggregate multinomial logit discrete choice model to determine flow volumes for each of the possible logistics chains. We achieve consistency between the gravity and logistics chain models by a joint estimation of unknown parameters. We use a new transport flow survey dataset produced by Statistics Netherlands with information on loading and unloading location types. This dataset allows the required model calibration with respect to regional warehouse throughput. The proposed logistics chain model produces accurate estimates of regional warehouse throughput volumes and plausible parameter values. In the paper we present the specification of the new model, the dataset used and the results of the estimation.
  Authors: Davydenko, Igor Y.; Tavasszy, Lóránt A. Antal
  Authors: Davydenko, Igor Y.; Tavasszy, Lóránt A. Antal
  Year: 2013
  Document Type: Paper
  Subject: Freight Transportation; Operations and Traffic Management; Terminals and Facilities
  Session: 248
  Paper Number: 13-3590
• INCREASING THE CAPACITY OF SIGNALIZED INTERSECTIONS BY DYNAMICALLY USING EXIT-LANES FOR LEFT-TURN TRAFFIC
  Abstract: Many congested intersections have heavy traffic volumes on movements where there is insufficient capacity due to geometric limitations. This paper presented an unconventional approach to increase the capacity of heavily congested intersections: it opens up exit-lanes for left-turn traffic dynamically with the help of an additional traffic light installed at the median opening (the pre-signal), which we shall refer as the exit-lanes for left-turn (EFL) control. Based on this concept, an optimization problem for the EFL was formulated as a Mix-Integer-Non-Linear-Program (MINLP), in which the geometric layout, main-signal timing and pre-signal timing were integrated. The MINLP was solved by transforming it into a series of Mix-Integer- Linear-Programs (MILPs). The latter problem can be solved by the standard branch-and-bound technique. The results of extensive numerical analysis and VISSIM simulation showed that the EFL approach could increase intersection capacity and reduce traffic delay substantially, especially under high left-turn demand. Moreover, the EFL control can be applied to one or multiple arms simultaneously, thus it is particularly useful for intersections with unbalanced left demand and degree of saturation among different travel directions.
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-2989
• Effective Coordinated Optimization Model for Transit Priority Control Under Arterial Progression
  Abstract: Aiming at providing effective priority control for transit as well as minimizing the adverse impacts on passenger car movements along the arterial, this paper presents an effective coordinated transit priority control optimization model which has the following features: (1) the control unit is defined as the coordinated intersection group between two successive bus stops; (2) buses are detected after leaving the upstream stop before their arrival at the first intersection of a control unit; (3) the dynamic interactions of priority strategies between adjacent intersections within a control unit are modeled using a bus delay model and an ineffective priority time model; (4) a linear program model is developed to generate the optimal priority strategies to reduce the bus travel time in case of priority is necessary and ensure every priority treatments implemented at each intersection is effective. Extensive experimental analyses, including time-space diagram based deterministic analysis and simulation based analysis were performed, and results were compared with the conventional transit signal priority strategy and no priority scenario. The proposed model presents promising outcomes in design of transit priority control signals in terms of decreasing bus delay, improving bus schedule adherence, and minimizing negative impacts on general traffic under different traffic demand patterns.
  Authors: Zhao, Jing; Ma, Wanjing; Head, Larry
  Authors: Zhao, Jing; Ma, Wanjing; Head, Larry
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3006
• Evaluation of Driver Performance and Distraction When Using In-Vehicle Signing Information
  Abstract: The goal of the study described in this report was to examine the in-vehicle signing (IVS) function of a hand-held device to determine the utility of the information and any potential distraction associated with the IVS information. Notification of speed zone changes along a roadway, of school zones, of construction zones and of curves were visually displayed on a personal navigation device (PND) to assist drivers with preparing for transitions to new driving situations. A continuous navigation function was provided in two of the three conditions to examine the effect of presenting navigation information alone, IVS information alone or both sources of information (IVS + Navigation) on driving performance. Sixty-one participants (balanced for gender and across age groups) completed the study, which involved performing a simulated drive in one of the conditions along 24-miles of Minnesota roadways. The driving performance results indicated minimal distraction while using the IVS information when changing speed zones. Drivers in the IVS alone condition spent significantly less time looking at the in-vehicle display than drivers who were presented with navigation information. Response times to a visual search task indicated that visual workload increased significantly during a speed transition zone regardless of whether IVS information and/or navigation information was presented or not (i.e., baseline drive). Overall, the project found that drivers may not always adjust speed accordingly when transitioning to new speed zones, even when IVS information is presented in addition to roadway signs.
  Authors: Creaser, Janet; Manser, Michael
  Authors: Creaser, Janet; Manser, Michael
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management; Safety and Human Factors
  Session: 470
  Paper Number: 13-3011
• Transit Priority Strategies for Multiple Routes Under Headway-Based Operations
  Abstract: This paper presents a transit signal priority (TSP) model designed to maximize the benefits of both bus riders and all intersection passenger car users. The proposed strategy, mainly for headway-based bus service, offers the responsible agency a reliable way to determine the extended green duration in response to multiple bus priority requests for different routes. Depending on the focus of applications, one can select a different control objective for different times of a day with our proposed TSP control logic. Using the field data from Jinan, China, the proposed strategy has shown its promise in reducing the bus passenger waiting time and the total intersection delay. Our further exploration with simulation experiments for sensitivity analysis has also found that TSP will be most effective if the ratio between bus and passenger volumes exceeds some threshold.
  Authors: Lin, Yongjie; Yang, Xianfeng; Chang, Gang-Len; Zou, Nan
  Authors: Lin, Yongjie; Yang, Xianfeng; Chang, Gang-Len; Zou, Nan
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3190
• Comprehensive Evaluation Framework of Traffic Calming Measures in Residential Area
  Abstract: Traffic calming measures are effective in enhancing traffic safety by reducing vehicle speeds. A variety of studies have evaluated the effectiveness of traffic calming measures to derive useful insights into the design and operations. Unlike existing studies focusing on either traffic performance measures or environmental impacts of the traffic calming devices, this study proposes a comprehensive evaluation framework based on microscopic traffic simulations, which enables more reliable and systematic identification of benefits for calming measures. The proposed framework evaluates the effectiveness of various traffic calming measures through three major perspectives including traffic performance, traffic safety, and environmental and public health impact. Four different traffic calming measures, two types of speed humps, speed tables, and chicanes, were applied to the proposed framework to demonstrate its usefulness and applicability. A field experiment using probe vehicles equipped with a global positioning systems (GPS) device were conducted to obtain vehicle trajectory data to be used for more realistic simulations. Also, a recently developed vehicle emissions model was used to evaluate environmental and public health impacts. Results show that speed tables and chicanes outperform others. It is expected that the outcome of this study will be a valuable decision making tool for evaluating traffic calming measures.
  Authors: Lee, Gunwoo; Joo, Shinhye; Oh, Cheol; Choi, Keechoo
  Authors: Lee, Gunwoo; Joo, Shinhye; Oh, Cheol; Choi, Keechoo
  Year: 2013
  Document Type: Paper
  Subject: Ope