2013 Session: 497

• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• Cooperative Highway Traffic: Multiagent Modeling and Robustness Assessment to Local Perturbations
  Abstract: As cooperative systems, a.k.a. connected vehicles, enable the communication and exchange of information between vehicles and infrastructure, it is expected that their communication capabilities can lead to a better dynamic traffic management on urban motorways. In such a context, technological constraints must be the basis for any management strategy. If it has been analytically proven that communication can help stabilize traffic flow at a microscopic level, it is interesting to evaluate realistic communication strategies taking into consideration multiple perturbations such as sensors errors or driver cooperation. In this paper, a three-layer multi-agent framework is used to model and control the homogenization of traffic flow based on stability criteria. The physical layer coordinates the movement of vehicles based on traffic dynamics. This layer includes cooperation derived from the communication and trust layers that respectively manage information and its reliability. Simulation results highlight the positive impacts of communication and control on traffic flow stability.
  Authors: Monteil, Julien Georges; Billot, Romain; Sau, Jacques; Armetta, Frédéric; Hassas, Salima; El Faouzi, Nour-Eddin
  Authors: Monteil, Julien Georges; Billot, Romain; Sau, Jacques; Armetta, Frédéric; Hassas, Salima; El Faouzi, Nour-Eddin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-4063
• Variable Speed Limit Control Based on Extended Link Transmission Model
  Abstract: In this paper, the link transmission model (LTM) is extended to include the effects of variable speed limits(VSL) and consequently to provide variable speed limit control for traffic networks modeled by LTM. The LTM has recently been developed for route assignment, but in this paper the LTM is modified to be used for control purposes. By this we achieve a model that provides a balanced trade-off between accuracy and computational complexity, and hence it is useful for on-line model-based traffic control.Nevertheless, the extension of the model for ramp metering and speed limit control needs careful attention. Since the LTM lacks explicit velocity equations focus is on other potential sources that could imitate the influences of VSL. The delays inside the model are manipulated in order to achieve the mentioned goal. Moreover, we take into account different situations that may occur in reality based on changes in VSL and different traffic conditions. Finally, the total extensions are verified using simulation and real data. To this aim, the VSL extension integrated in the LTM is verified using simulations for a benchmark case study (in order to show performance of the extended LTM clearly). Next, the LTM is calibrated by real data collected from the A12 Freeway in The Netherlands. The optimal parameters of the model are identified using a global optimization method. Comparison with real data from a period of time that VSL installed on the freeway are active, shows acceptable performance of the total extended and calibrated LTM.
  Authors: Hajiahmadi, Mohammadreza; Corthout, Ruben; Tampere, Chris; De Schutter, Bart; Hellendoorn, Hans
  Authors: Hajiahmadi, Mohammadreza; Corthout, Ruben; Tampere, Chris; De Schutter, Bart; Hellendoorn, Hans
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0409
  Practice-Ready: Yes
• Simulation-Based Assessment of Double-Parking Impacts on Traffic and Environmental Conditions
  Abstract: The objective of this research is to estimate the impacts that a specific pattern of illegal parking (double-parking) has on traffic conditions and the environment, using microscopic simulation. Through a sensitivity analysis, the impacts of illegal double-parking on average speed, delay and stopped time were estimated. Results show that the existence of the phenomenon entails a severe decrease on average speed and an important increase of delay and stopped time. Through the case study the impacts that a reduction or an elimination of the phenomenon will have in a real network were evaluated: all traffic indicators would be improved if double-parking were suppressed partially (e.g. through an intensification of enforcement) or, even better, completely. The results show that limiting double-parking could result in an increase in speeds of about 10-15% and a decrease of about 15% and 20% for delay and stopped time respectively. However, even greater improvements may be achieved if double-parking is eliminated: average speed can increase by up to 44%, while delay and stopped time can decrease by up to 33% and 47% respectively. Based on the results extracted from the case study, an assessment of the impacts for the whole district of the Municipality of Athens, as well as for the entire Athens region was conducted, using several indices and performance measures. Savings from lost time and reduced CO2, CO and HC emissions were calculated. Directions for future research are also proposed.
  Authors: Kladeftiras, Markos; Antoniou, Constantinos
  Authors: Kladeftiras, Markos; Antoniou, Constantinos
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1791
  Practice-Ready: Yes
• Short-Term Online Queue Predictor Based on Cell Transmission Model and Unscented Kalman Filter
  Authors: Dantas, Luciano
  Authors: Dantas, Luciano
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0965
• Novel Cell Transmission Model-Based Simulations of Left-Turn Blockages Inside Intersections
  Authors: Jones, Steven
  Authors: Jones, Steven
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1003
• Relating Shockwave Propagation Speed and Time Headway Using Microscopic Analysis
  Authors: Stanitsas, Panagiotis
  Authors: Stanitsas, Panagiotis
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1075
• Traffic Flow with Increasing Density Assuming a Simple Safe Stopping Distance Formula
  Authors: Zarrillo, Marguerite
  Authors: Zarrillo, Marguerite
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1765
• Making NGSIM Data Usable for Studies on Traffic Flow Theory: Multistep Method for Vehicle Trajectory Reconstruction
  Authors: Montanino, Marcello
  Authors: Montanino, Marcello
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1739
• Simulation-Based Assessment of Double-Parking Impacts on Traffic and Environmental Conditions
  Authors: Antoniou, Constantinos
  Authors: Antoniou, Constantinos
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1791
• Investigation of Early-Onset Breakdown Phenomenon at Urban Expressway Bottlenecks in Shanghai, China
  Authors: Sun, Jian
  Authors: Sun, Jian
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2105
• Investigation of Early-Onset Breakdown Phenomenon at Urban Expressway Bottlenecks in Shanghai, China
  Authors: Zhang, Juan
  Authors: Zhang, Juan
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2105
• Cooperative Highway Traffic: Multiagent Modeling and Robustness Assessment to Local Perturbations
  Authors: Monteil, Julien
  Authors: Monteil, Julien
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-4063
• Variable Speed Limit Control Based on Extended Link Transmission Model
  Authors: Hajiahmadi, Mohammadreza
  Authors: Hajiahmadi, Mohammadreza
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0409
• Impact of Traffic Dynamics on Macroscopic Fundamental Diagram
  Authors: Knoop, Victor
  Authors: Knoop, Victor
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0595
• Spatial and Temporal Correlation of Freeway Link Speeds: Empirical Study
  Authors: Rachtan, Piotr
  Authors: Rachtan, Piotr
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0598
• Developing Algorithms for Real-Time Delay Estimation at Signalized Intersections Using Vehicle Arrival and Departure Times
  Authors: Saito, Mitsuru
  Authors: Saito, Mitsuru
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0599
• Impact of Signal Phasing Information Accuracy on Green Light-Optimized Speed Advisory Systems
  Authors: Stevanovic, Aleksandar
  Authors: Stevanovic, Aleksandar
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-0641
• Impact Assessments of On-street Parking Guidance System on Mobility and Environment
  Authors: Moini, Nadereh
  Authors: Moini, Nadereh
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1615
• Exploration of Lane Changing Behavior on Freeways
  Authors: Hill, Corey
  Authors: Hill, Corey
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2199
• Modeling and Analysis of Car-Truck Heterogeneous Traffic Flow Based on Intelligent Driver Car-Following Model
  Authors: Yang, Da
  Authors: Yang, Da
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-2358
• Inhomogeneous Flow Patterns in Undersaturated Road Networks and Implications for Macroscopic Fundamental Diagram
  Authors: Doig Godier, Jean
  Authors: Doig Godier, Jean
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1371
• Modeling Mandatory Lane Changing Using Bayes Classification and Decision Trees
  Authors: Hou, Yi
  Authors: Hou, Yi
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1359
• Modeling Mandatory Lane Changing Using Bayes Classification and Decision Trees
  Authors: Sun, Carlos
  Authors: Sun, Carlos
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1359
• Car-Following Behavior at Sags and Its Impacts on Traffic Flow
  Authors: Goni Ros, Bernat
  Authors: Goni Ros, Bernat
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 497
  Paper Number: 13-1907