2013 Session: 726

• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• 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
• Characteristics of Mixed Nonmotorized Traffic Flow: Comparative Analysis with Motorized and Pedestrian Traffic Flow
  Abstract: Non-motorized traffic flow relationships and characteristics are essential for the management and design of non-motorized traffic facilities. In this paper, the volume-density, speed-density and speed-volume relationships were analyzed separately with scatter plots and the models were developed. By comparative analysis with motorized and pedestrian traffic flow, their similarities and differences with non-motorized traffic flow were probed into. And the causes of the similarities and differences were analyzed. The fuzzy and unobserved characteristics of non-motorized traffic flow can be clear by comparative analysis. First, the volume-density relationships of them are similar, while that of mixed non-motorized and motorized traffic flow are both parabolic curves. The volume first increases and then decreases with the increase of density. The achievable volume of non-motorized traffic with either bicycles or mopeds as the majority is higher than that of mixed non-motorized traffic with both bicycles and mopeds. Thus, separating the bicycle and moped when they compose similar percentages is recommended. Second, the speed tends to decrease with the increase of density in all the three traffic flows. The speed-density and speed-volume relationships of mixed non-motorized traffic flow cover a right trapezoid area, while those of motorized and pedestrian traffic flow both follow some curves. The difference is caused by the varied speed distribution of the three traffic flows. These findings give a skeleton of mixed non-motorized traffic flow characteristics and support future studies on mixed non-motorized traffic flow theory.
  Authors: Chen, Xiaohong; Lin, Bin; Han, Hui
  Authors: Chen, Xiaohong; Lin, Bin; Han, Hui
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3532
• Complexity of Driving Tasks: Analysis of Compensation and Performance Effects in Longitudinal Driving Behavior
  Abstract: Complexity of the driving task has been shown to have a substantial influence on longitudinal driving behavior. In the proposed theoretical framework changes in longitudinal driving behavior are divided into compensation and performance effects. It is however not yet clear to what extent changes in the complexity of the driving task actually leads to compensation and performance effects. To this end in this contribution we report the results of a driving simulator study aimed at simulation a complex driving condition (i.e., narrow lanes with roadside concrete barriers). Through analyses we show that a change in the complexity if the driving task has a substantial influence on compensation effects, represented by changes in speed and spacing. We also show that a substantial influence on performance can be observed, represented by changes in the perceptual thresholds, changes in the sensitivity of accelerations towards lead vehicle related stimuli and so-called inter-decision times (elapsed times between changes in acceleration). The contribution finishes with a discussion and recommendations for future research.
  Authors: Hoogendoorn, Raymond Gerard; van Arem, Bart; Hoogendoorn, Serge; Brookhuis, Karel A.
  Authors: Hoogendoorn, Raymond Gerard; van Arem, Bart; Hoogendoorn, Serge; Brookhuis, Karel A.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3653
• Microscopic Analysis of Traffic Behavior at Uncontrolled Intersections in India
  Abstract: Unsignalized intersections in India are uncontrolled, and are characterized by chaotic traffic situation and have become accident hot spots. In this study, we have collected traffic data at three uncontrolled intersections and analyzed traffic parameters such as traffic composition, speed variations, lane distribution, trajectories, conflict points, and pedestrian movements. At each intersection, three cameras are used to record the traffic simultaneously from different angles. Among the intersections for which data are extracted, one each is from city centre (Type I), suburb (Type II), and outskirt (Type III). Type I intersection has a large number of slow moving vehicles interacting with closely spaced other vehicles and pedestrians. Type I intersection has more than 70% vehicles as two-wheelers; the proportion at type II and type III intersections are about 50%. All the vehicle classes prefer inner lane, except auto-rickshaws. The speed on inner lane is higher than outer lane vehicles as latter are affected by the roadside friction. It is also found that the minor approach vehicles have to slow down or stop many times. Right turning two-wheeler trajectories are studied which showed that the trajectories are much flatter than the trajectories in the standard conflict point diagram. Consequently the conflict points of right turning two-wheelers are moved apart from each other creating a rhombus instead of standard rectangle. Vehicle-pedestrian conflicts are very critical as many pedestrians try to walk the shortest distance without giving much attention to their safety. This study has great potential in assessing the performance and safety of an unsignalized intersection in India.
  Authors: Pawar, Digvijay Sampatrao; Patil, Gopal R.
  Authors: Pawar, Digvijay Sampatrao; Patil, Gopal R.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4254
• Empirical Evidence on the Existence of Collateral Anomaly
  Abstract: Two-dimensional microscopic traffic models have been introduced in recent years, opening new lines of research. If properly developed, they may allow more accurate reproduction of traffic behavior, enhancing the effectiveness and application field of traffic simulation.This work analyses a particular behavior of drivers regarding the second dimension of driving (the lateral direction) that we call collateral anomaly. It encompasses the peculiar decisions and actions taken by them when two vehicles are right next to each other. In order to achieve that, data extracted from trajectories observed in U. S. highways is used. After the analysis, we discuss how these results, as well as others previously reported by different authors, are consistent with the idea of collision avoidance maneuvers executed by drivers due to sudden changes in the trajectories of neighboring vehicles. To verify this behavior on drivers is critical to characterize the way in which vehicles move in the lateral direction. The inclusion of such a behavior into a traffic model might improve the accuracy of traffic modeling, and would help to understand other behaviors observed in the field, which might be related with the lateral movement of vehicles, such as the relaxation phenomenon (Laval and Leclercq, 2008), or the influence of the lane’s and vehicle’s width in traffic (Bartel et al., 1997).
  Authors: Delpiano, Rafael; Herrera, Juan Carlos; Coeymans, Juan Enrique
  Authors: Delpiano, Rafael; Herrera, Juan Carlos; Coeymans, Juan Enrique
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4333
• Lagrangian-Based Hydrodynamic Model: Freeway Traffic Estimation
  Abstract: This paper is concerned with highway traffic estimation using traffic sensing data, in a Lagrangian-based modeling framework. We consider the Lighthill-Whitham-Richards (LWR) model (Lighthill and Whitham, 1955; Richards, 1956) in Lagrangian-coordinates, and provide rigorous mathematical results regarding the equivalence of viscosity solutions to the Hamilton-Jacobi equations in Eulerian and Lagrangian coordinates. We derive closed-form solutions to the Lagrangian-based Hamilton-Jacobi equation using the Lax-Hopf formula (Daganzo, 2005; Aubin et al., 2008), and discuss issues of fusing traffic data of various types into the Lagrangian-based H-J equation. A numerical study of the Mobile Century field experiment (Herrera et al., 2009) demonstrates the unique modeling features and insights provided by the Lagrangian-based approach.
  Authors: Han, Ke; Yao, Tao; Friesz, T. L.
  Authors: Han, Ke; Yao, Tao; Friesz, T. L.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4510
• Empirical Analysis of Discretionary Lane Changes Using Probabilistic Models
  Abstract: This paper presents a stochastic approach for modeling discretionary lane changes with influential factors of velocity and spacing advantages. Lane changes are categorized into mandatory lane changes and discretionary lane changes. There are various factors which influence the decision-making involved in discretionary lane changes, including: for examples, relative velocity between target lane and original lane, and lead and lag gaps. This paper studies how velocity and spacing advantages affect the discrete lane change. This project uses Next Generation Simulation (NGSIM) data from traffic on U.S. Highway 101 and Interstate 80. Mandatory lane changes due to exiting/entering roadway ramps at the target site were filtered out using the proposed standards, in addition to some of the observed discretionary lane changes which were deemed false positives, but confident discretionary lane changes were considered. Driver behavior differs for mandatory and discretionary lane changes. This study proposes the use of an exponential probability function model with speed difference and lead gap difference between the target lane and the original lane, and proposes some restrictions of discretionary lane changes empirically. By transformed linear regression, these traffic variables have actual influences on the choice probability function of discretionary lane changes. Understanding the behavior of discretionary lane changes is important in safety, and may improve safety-related technologies
  Authors: Lee, Jinwoo; Yeo, Hwasoo
  Authors: Lee, Jinwoo; Yeo, Hwasoo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4629
• Traffic Hysteresis and Evolution of Stop-and-Go Oscillations
  Abstract: This paper shows that traffic hysteresis, a manifestation of driver characteristics, has a profound impact on the development of traffic oscillations. Findings suggest that aggressive drivers (with small response times and jammed spacing) are responsible for spontaneous formations of oscillations. Furthermore, aggressive drivers tend to exhibit large clockwise hysteresis loops, which instigate the transition from precursor to well-developed oscillations that propagate in space. Once formed, the oscillations exhibit four development stages: precursor, growth, stable, and decay stages. Each stage is characterized by distinct hysteresis orientations (e.g., clockwise vs. counter-clockwise loops) and magnitude. Oscillations grow significantly in amplitude in the precursor and growth stages in which clockwise hysteresis is prevalent. Statistical results further confirm high correlation between growth in oscillations amplitude and hysteresis magnitude.
  Authors: Chen, Danjue; Ahn, Soyoung; Laval, Jorge Andres; Zheng, Zuduo
  Authors: Chen, Danjue; Ahn, Soyoung; Laval, Jorge Andres; Zheng, Zuduo
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4611
• Calibration of Microsimulation Model With and Without Network Incidents
  Abstract: Incidents, pre-programmed or random, are major sources of congestion on urban freeways. With many urban freeways in the United States operating close to capacity, the need to reduce the impact of incident-related congestion has become critical. Incident Management Strategies (IMS), when properly developed and deployed, have the potential to reduce such urban congestion. The problem addressed in this paper deals with the question of dynamically finding alternate paths in a given network when a section of the network is temporarily incapacitated because of incidents. Instant knowledge of such alternate paths with surplus capacities may enable Traffic Management Centers (TMC) to efficiently divert traffic from the affected portion of the network, thereby helping alleviate congestion. As a part of this effort, the authors adapted a micro-simulation model AIMSUN to assess the impact of deploying IMS’s on an urban network. This paper deals with a major focus area of this study, calibration of the micro simulation model.The calibration of the proposed model is demonstrated on a heavily traveled portion of an urban network in the Detroit metropolitan region. The network contains two freeways in the north-south and east-west directions (Interstate 75 and Interstate 696) instrumented with various ITS devices, and a number of major arterials. The model calibration process is conducted in two separate channels. Initially, the model is calibrated without any incident data. Upon completion of no-incident calibration, the model is further validated with incident data. Travel time and traffic volume data (in 5 minute increments) were obtained from sensors installed by the Michigan Department of Transportation at strategic locations on the two freeways. A set of statistical tests are reported that shows excellent correlation between the observed data and the model output. The calibrated model with extensive field data may be used as a tool to assess the traffic consequences of various IMS’s.
  Authors: Khasnabis, Snehamay; Mishra, Sabyasachee; Swain, Subrat Kumar; Elibe, Elibe Ama
  Authors: Khasnabis, Snehamay; Mishra, Sabyasachee; Swain, Subrat Kumar; Elibe, Elibe Ama
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4655
• Conflicts and Delay of Two-Way Traffic Sharing a Single-Way Path
  Abstract: Serving two-way traffic in a single-way path is needed in some circumstances. When traffic demands are low, vehicles in two opposing directions may share a single-way path without much problem. With the demands increasing, however, the possibility of conflict is getting larger and eventually conflict becomes unavoidable. In case of no signalization, the following scenario is considered in this paper that opposing traffic arriving at both ends of a single-way path negotiates, based on the first-come-first-serve rule, to avoid unsolvable conflict within the path. In particular, a latecomer has to wait at her entry of the path until an early bird from the other entry and possibly some of its followers to first go across the path. Consequently, a queue may build up behind the latecomer. When traffic demands get even bigger, alternating queues are expected at either entry of the path. This paper examines the probability that typical conflict occurs in this scenario as well as average queueing delay resulting. Mathematical analysis is conducted also to reveal basic features of alternating queues. The obtained theoretical results are crucial for decision-making concerning the usage of a single-way path to serve two-way traffic in case of needs. Further theoretical work and simulation studies are outlined.
  Authors: Wang, Yibing
  Authors: Wang, Yibing
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4881
• Hamilton-Jacobi Partial Differential Equation and Three Representations of Traffic Flow
  Abstract: This paper applies the theory of Hamilton-Jacobi partial differential equations to the case of traffic flow. The traffic flow surface is analyzed with respect to the three 2-dimensional coordinate systems arising in the space of vehicle number, time and distance. In each case, the solution to the initial and boundary value problems are presented. Explicit solution methods and examples are shown for the triangular flow-density diagram case. This unveils new models and shows how a number of existing models are cast as special cases.
  Authors: Laval, Jorge Andres; Leclercq, Ludovic
  Authors: Laval, Jorge Andres; Leclercq, Ludovic
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4882
• Logit Lane Assignment Model: First Results
  Abstract: The Logit lane assignment model has been introduced recently in order to describe multi-lane traffic flow from a macroscopic point of view. The model is based on the idea that each available lane has a specific utility for each driver, who chooses the lane with the highest utility. The model is expressed by a system of conservation laws with a smooth but implicitly defined flux function. The first aim of the paper is to explore on two data-sets how traffic data supports the fact that traffic speed constitutes an explanatory variable of lane assignment. Second the paper addresses the problem of discretization of the model. Several numerical schemes are proposed: Lax-Friedrichs, Euler-lagrange remap, Lagrange, and their convergence properties are illustrated on the treatment of the Riemann problem. Directions for future research are outlined
  Authors: Lebacque, Jean-Patrick
  Authors: Lebacque, Jean-Patrick
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4867
• Variational Formulation of Multiclass Traffic Flow Models: Theory and Applications
  Abstract: Since 1970s, various multi-class traffic flow models have been proposed to address different empirical observations, behavioral postulations and practical needs. In this paper, we present a variational theory of multi-class traffic flow models. This theory extends the minimum principle, namely variational formulation, of the classical Lighthill-Whitham-Richards (LWR) model. We demonstrate that this theory actually bridges the traffic flow models with an optimal control problem associated with an auxiliary system of conservation laws. We develop the variational formulation of a multi-class model explicitly. Utilizing the variational character of the multi-class traffic flow models, we are able to devise a simple numerical scheme for solving them. Numerical experiments indicate the effectiveness of the proposed solution scheme.
  Authors: Li, Jia; Zhang, H. Michael
  Authors: Li, Jia; Zhang, H. Michael
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-5148
• New Consistency Index Based on Inertial Operating Speed
  Abstract: Road crashes occurrence depends on several factors, being the design consistency one of the most important. It refers to the conformance of highway geometry to drivers’ expectations.A new consistency model for evaluating the performance of tangent-to-curve transitions at two-lane rural roads is presented. It is based on the Inertial Consistency Index (ICI), defined for each transition. It is calculated at the beginning point of the curve, as the difference between the average operating speed of the previous 1 km road segment (inertial operating speed) and the operating speed at this point.88 road segments, which included 1,686 tangent-to-curve transitions, were studied in order to calibrate ICI and its thresholds. The relationship between those results and the crash rate associated to each transition has been analyzed. It has been pointed out that the higher the ICI is, the higher the crash rate is, thus increasing the probability of accidents to take place. Similar results were obtained from the study of the relationship between ICI and the weighted average crash rate of the corresponding group of transitions.A graphical and statistical analysis established that road consistency may be considered good when ICI is lower than 10 km/h; poor when ICI is higher than 20 km/h; and fair otherwise.A validation process has been carried out considering 20 road segments. The obtained ICI values were highly correlated to the number of crashes occurred at the analyzed transitions. Hence, the Inertial Consistency Index (ICI) and its consistency thresholds resulted in a new approach for consistency evaluation.
  Authors: Garcia, Alfredo; Llopis-Castello, David; Camacho-Torregrosa, Francisco Javier; Perez-Zuriaga, Ana Maria
  Authors: Garcia, Alfredo; Llopis-Castello, David; Camacho-Torregrosa, Francisco Javier; Perez-Zuriaga, Ana Maria
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2694
  Practice-Ready: Yes
• Methodology for Calibration of VISSIM in Mixed Traffic
  Abstract: Mixed traffic, characterized by diverse vehicles, changing composition, lack of lane discipline, etc. is best modeled by micro simulation. However, the majority of the leading micro simulation packages and their calibration methodologies have been developed considering less complex homogeneous traffic. Hence, a methodology for calibrating a micro simulation model for mixed traffic is proposed. Driver behavior in mixed traffic is observed and adjustments were made to represent in the simulation. Calibration parameters were identified using multi parameter sensitivity analysis, and the optimum values for these parameters were obtained by minimizing the error between the simulated and field delay using a genetic algorithm. Multiple criteria were included in the optimization formulation by constraint insertion. The proposed methodology is illustrated using VISSIM, a widely used micro simulation software. Signalized intersections with different traffic characteristics from Mumbai are taken as case study.
  Authors: Manjunatha, Pruthvi; Vortisch, Peter; Mathew, Tom V.
  Authors: Manjunatha, Pruthvi; Vortisch, Peter; Mathew, Tom V.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3677
  Practice-Ready: Yes
• Delay Estimation Under A Dynamic Speed Control-Based Intersection
  Authors: Chen, Wenqing
  Authors: Chen, Wenqing
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2570
• Modeling Microscopic Freeway Traffic Using Cusp Catastrophe Theory
  Authors: Vlahogianni, Eleni
  Authors: Vlahogianni, Eleni
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2755
• Modeling Microscopic Freeway Traffic Using Cusp Catastrophe Theory
  Authors: Papacharalampous, Alexandros
  Authors: Papacharalampous, Alexandros
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2755
• Analytical Delay Model to Yielding Vehicles at Unsignalized Pedestrian Crossings
  Authors: Kumfer, Wesley
  Authors: Kumfer, Wesley
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-2881
• Asymptotic Stability of Boundedly Rational Day-to-Day Dynamic
  Authors: Di, Xuan
  Keywords: poster presentation; poster design; poster template
  Authors: Di, Xuan
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3287
• Complexity of Driving Tasks: Analysis of Compensation and Performance Effects in Longitudinal Driving Behavior
  Authors: Hoogendoorn, Raymond
  Authors: Hoogendoorn, Raymond
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3653
• Methodology for Calibration of VISSIM in Mixed Traffic
  Authors: Manjunatha, Pruthvi
  Authors: Manjunatha, Pruthvi
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3677
• Lagrangian-Based Hydrodynamic Model: Freeway Traffic Estimation
  Authors: Han, Ke
  Authors: Han, Ke
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4510
• Effect of Surrounding Traffic Characteristics on Lateral Movement Behavior in Heterogeneous Traffic Conditions
  Authors: Mantri, Sruthi
  Authors: Mantri, Sruthi
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3525
• Traffic Hysteresis and Evolution of Stop-and-Go Oscillations
  Authors: Ahn, Soyoung
  Authors: Ahn, Soyoung
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4611
• Variational Formulation of Multiclass Traffic Flow Models: Theory and Applications
  Authors: Li, Jia
  Authors: Li, Jia
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-5148
• A Heterogeneous Visual Imaging Model for Analyzing Impact of Vehicle Type on Car-Following Dynamics
  Authors: Jin, Jing
  Authors: Jin, Jing
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3126
• Modeling Reaction Time Within a Traffic Simulation Model
  Authors: Toledo, Tomer
  Authors: Toledo, Tomer
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3434
• Microscopic Analysis of Traffic Behavior at Uncontrolled Intersections in India
  Authors: Pawar, Digvijay
  Authors: Pawar, Digvijay
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4254
• Empirical Evidence on the Existence of Collateral Anomaly
  Authors: Delpiano, Rafael
  Authors: Delpiano, Rafael
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4333
• Empirical Analysis of Discretionary Lane Changes Using Probabilistic Models
  Authors: Lee, Jinwoo
  Authors: Lee, Jinwoo
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-4629
• A Heterogeneous Visual Imaging Model for Analyzing Impact of Vehicle Type on Car-Following Dynamics
  Authors: Zheng, Liang
  Authors: Zheng, Liang
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3126
• Characteristics of Mixed Nonmotorized Traffic Flow: Comparative Analysis with Motorized and Pedestrian Traffic Flow
  Authors: Lin, Bin
  Authors: Lin, Bin
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3532
• Driver Mandatory Lane Change Behavior: Use of Governing Gap in Critical Gap Estimation
  Abstract:

  This study analyzed the driver gap acceptance and rejection behavior during mandatory lane changes on a multilane freeway. During a lane change, drivers were more receptive to either the leading or the trailing gaps with vehicles in the target lane which governed the drivers’ lane change and is termed as the governing gap. Drivers maneuvered till the governing gap was greater than the critical gap, then accepted the gap and made a lane change. In this process, drivers reduced the non-governing gap to increase the length of the governing gap. The drivers, as a result, were found to be consistent with respect to the governing gap and inconsistent with respect to the non-governing gap. The governing gap, therefore, addresses the consistent driver behavior and avoids categorization of drivers as inconsistent. Consistent driver behavior is further augmented in this paper by considering the largest rejected less than the accepted gap (LRLA) as the effective rejected gap. Critical gaps were estimated based on the accepted and LRLA gaps, firstly, by categorizing the drivers based on the governing gap and the type of maneuver, and secondly, by categorizing the drivers based on the relative speeds. For a simple lane change model, categorization by governing gap and type of maneuver will be sufficient with a critical gap value distribution defined by empirical data. For a sophisticated lane change model, in addition to maneuver types, critical gaps estimated based on difference in relative speeds will help better replicate the realistic lane change behavior of drivers.

  Authors: Bham, Ghulam Hussain; Kandada, Srinadh
  Authors: Bham, Ghulam Hussain; Kandada, Srinadh
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-5151
  Practice-Ready: Yes
• Toward Capturing Sources of Travel Time Unreliability in Microscopic Traffic Models: Driver Heterogeneity, Flow Breakdown, and Crash Occurrence
  Abstract:

  Travel time reliability impacts traveler decision making especially under congested traffic conditions. Several factors are identified as the causes of unreliability in transportation networks. Among those, crashes (and near-crashes) and heterogeneity across drivers are two factors directly related to the behavior of drivers, but which are not typically captured in existing microscopic simulation tools. This paper presents an effort that relies on a cognitive risk-based microscopic model that is capable of considering crash occurrence endogenously, to investigate the importance of considering the drivers’ heterogeneity and incidents in microscopic simulation models to study the travel time reliability. Two highway segments in Chicago, IL and New York, NY are simulated using as input actually observed traffic data as well as output from a mesocopic simulation model. The simulation results are then validated against the actual observations. Different heterogeneity consideration methods are compared and the results show the importance of considering correlation among model parameters to reduce the bias in estimating the travel time and travel time reliability. Finally, the safety related feature of the model are investigated and validated against the actual crash data.

  Authors: Talebpour, Alireza; Mahmassani, Hani S.; Kim, Jiwon
  Authors: Talebpour, Alireza; Mahmassani, Hani S.; Kim, Jiwon
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-5347
• Modeling Reaction Time Within a Traffic Simulation Model
  Abstract:

  Human reaction time presents a significant influence when modeling human behavior at a microscopic level. In reality drivers and pedestrian do not react to an event instantaneously; rather, they take time to perceive the event, process the information, decide on a response and finally enact their decision. All these processes introduce delay. As people are simulated at increasingly fine-grained resolutions, it becomes critical to consider the delay due to reaction time if one is to achieve accurate results. In this paper we detail the framework which we are developing within the SimMobility Short Term Simulator (a microscopic traffic simulator) which is capable of modeling reaction time for each person in a detailed, flexible manner. Most existing simulators over-simplify the reaction time implementation within the simulation to reduce computational overhead and memory requirements. Here, however, we present a framework which will enable modelers to set realistic reaction time values, relying on the simulator to handle implementation and optimization considerations. Following this, we report our findings concerning the impact of reaction time on traffic dynamics across several simulation scenarios. The findings indicate that in the presence of reaction time, the traffic dynamics produces more realistic traffic condition.

  Authors: Basak, Kakali; Hetu, Seth; Li, Zhemin; Lima Azevedo, Carlos; Loganathan, Harish; Toledo, Tomer; Xu, Runmin; Xu, Yan; Peh, Li-Shiuan; Ben-Akiva, Moshe E.
  Authors: Basak, Kakali; Hetu, Seth; Li, Zhemin; Lima Azevedo, Carlos; Loganathan, Harish; Toledo, Tomer; Xu, Runmin; Xu, Yan; Peh, Li-Shiuan; Ben-Akiva, Moshe E.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 726
  Paper Number: 13-3434