2013 Session: 430

• Evaluation of InSync Adaptive Traffic Signal Control in Microsimulation Environment
  Abstract: InSync, an ATCS developed and supported by Rhythm Engineering, is one of the youngest ATCSs on the market. Yet, dozens of InSync systems were recently deployed around the country. InSync has been evaluated in microsimulation before. However, previous attempts lacked: a rigor of scientific approach, effort to carefully build a field-like microsimulation model, and analysis that investigates a comprehensive set of performance measures including environmental and safety metrics. This study addresses these issues by evaluating performance of InSync on segment of SR 421 - a 12-intersection corridor in Volusia County, FL. InSync adaptive traffic control logic has been compared to three conventional Time-Of-Day signal timings plans in a virtual reality of microsimulation model. VISSIM model of SR 421 was carefully calibrated and validated to resemble field conditions as much as possible. Each of scenarios was simulated multiple times and results were tested for statistical significance. Findings show that InSync outperforms TOD signal timings in terms of traffic efficiency. Savings vary between 2-20% depending on a particular performance measure and time of the day. In terms of environmental factors and surrogate safety measures InSync also outperforms TOD signal timings but sometimes it pays the price of enabling more efficient traffic operations than the TOD plans. Further research is necessary to investigate InSync benefits in the environment of volatile changes in traffic flows.
  Authors: Stevanovic, Aleksandar; Zlatkovic, Milan
  Authors: Stevanovic, Aleksandar; Zlatkovic, Milan
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0487
• Intelligent Transportation System Application: Design and Evaluation of Intelligent Dilemma-Zone Protection System for High-Speed Rural Intersection
  Abstract: This paper presents the design and evaluation of a dilemma zone protection system that utilizes the dynamic detection technology to track individual vehicles as they approach an intersection of interest. A high-speed rural intersection in Maryland experiencing a high frequency of crashes was selected for system installation and evaluation. Data collected from 3 microwave sensors deployed along the target approach were used in real time to control the signal logic, providing green or all-red extensions when the pre-defined parameters of detected vehicles are met. To evaluate the performance of the system design and the effectiveness of the associated parameters, a field test was further conducted. The data analysis included the identification of false called red extensions (related to efficiency) and missed red extensions (related to safety) to assess the overall performance of the newly installed system. Results indicate that the newly designed dynamic dilemma zone protection system using an all-red extension offers distinct advantages over traditional systems by providing additional protection to high-speed vehicles even when they are in the “cannot pass zone” and make incorrect passing decisions.
  Authors: Chang, Gang-Len; Franz, Mark L; Liu, Yue; Lu, Yang (Carl); Tao, Ruihua
  Authors: Chang, Gang-Len; Franz, Mark L; Liu, Yue; Lu, Yang (Carl); Tao, Ruihua
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0973
• Longitudinal Performance Measures for Assessing Agencywide Signal Management Objectives
  Abstract: A fundamental concept of system engineering is defining operating objectives. Once those are defined, it is important to select the appropriate strategy and performance measure for assessing how well the strategy is working. This paper identifies two operating objectives that we feel are broadly shared by many agencies: i) Good communication to traffic signal infrastructure and ii) Good allocation of green times. One of these objectives is clearly oriented at asset management, and the other at operations. However, there are substantial synergies between both objectives. This paper proposes performance measures for evaluating whether those objectives are being met. The quality of communication is evaluated by examining connectivity and data completeness based on an open standard telecommunications model. Opportunities to improve green time allocation are detected by identifying patterns in phase events. The performance measures are presented in an easy-to-understand visual format that we believe is useful for practitioners. One of the outcomes of this system engineering approach is the realization that many of our objectives can be achieved with a high-latency, low-bandwidth communication infrastructure, provided the appropriate processing techniques and performance measures are clearly articulated. The paper illustrates explains this architecture and performance measures in the context of a deployment of 125 intersections geographically distributed throughout the state of Indiana using a variety of communication infrastructure ranging from commercial cellular data to agency-owned fiber.
  Authors: Li, Howell; Hainen, Alexander Michael; Day, Christopher M.; Grimmer, Gannon; Sturdevant, James R.; Bullock, Darcy M.
  Authors: Li, Howell; Hainen, Alexander Michael; Day, Christopher M.; Grimmer, Gannon; Sturdevant, James R.; Bullock, Darcy M.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0980
• Providing Speed Advice to Vehicles Approaching an Intersection: Evaluation and Lessons Learned
  Abstract: In this paper an Optimized Dynamic Speed Advise (ODYSA) system is evaluated. This system was developed by DTV Consultants and recently (2010) implemented in the Netherlands in the province Zuid-Holland. ODYSA is designed to minimize, or at least reduce, the number of times the main stream traffic flow is forced to stop due to the presence of traffic lights at intersections. It does so combining traditional signal coordination and the provision of speed advises to vehicles. This system is relatively new in the Netherlands and there are plans to extend its use. The results from the evaluation in terms of fluidity of traffic are positive and promising but, as will be discussed in this paper, some difficult and major issues regarding fine-tuning of the speed advises and the Human Factors interaction with the system should be addressed first.
  Authors: van Katwijk, Ronald; Bakri, Taoufik; Vukovic, Damir; Hogema, Jeroen H.; Steendijk, John
  Authors: van Katwijk, Ronald; Bakri, Taoufik; Vukovic, Damir; Hogema, Jeroen H.; Steendijk, John
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-1019
• Two-Step Optimization Model for Dynamic Lane Assignment at Isolated Signalized Intersections
  Abstract: At isolated signalized intersections, the congestion problem is partly caused by the unbalance of supply and demand which may be due to the variability of turning movement volumes. Although the signal timing can be adjusted to handle varying demand, its effect alone is limited, especially when the traffic demand fluctuates significantly. This paper presented a two-step optimization model for dynamic lane assignment to overcome this shortcoming of static lane markings and fully utilize the existing traffic facilities. The first step was to obtain the best lane assignment scheme by an arm-group based Integer-Non-Linear-Program model. The second step was to identify a suitable implementation scheme by determining a binary-type threshold. The results of VISSIM simulation showed that the proposed model could smartly choose the occasion to change the lane assignment by ignoring the small volume fluctuation and improve the traffic operation effectively when the traffic demand varies significantly.
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-1882
• Estimating Queue Distance Under Connected Vehicle Technology: Using Probe Vehicle, Loop Detector, and Fused Data
  Abstract: With the emergence of the Connected Vehicle technology, estimating the queue distance using probe trajectory data has recently received considerable attention. Different from data collected at loop detectors, probe trajectory data can provide a lower bound on the queue distance even if the market penetration rate is low. In this paper, we develop an event-based method that uses both probe trajectory and signal timing data to estimate the queue length. The estimation accuracy under different market penetration rates is then examined. We also develop a data fusion method that combines probe trajectory data and loop detector data. We then investigate when the data fusion method is expected to work well. Case studies are conducted using microscopic simulation data, and some observations are made.
  Authors: Li, Jing-Quan; Zhou, Kun; Shladover, Steven E.; Skabardonis, Alexander
  Authors: Li, Jing-Quan; Zhou, Kun; Shladover, Steven E.; Skabardonis, Alexander
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-2274
• Long Queue Estimation Using Short Vehicle Trajectories for Signalized Intersections
  Abstract: Queue length is one of the key components in traffic monitoring and signal control at arterial intersections. For congested links, queues are difficult to measure or estimate from either loop detectors or mobile sensors, as they may exceed the region of detection. In this paper, a queue length estimation model is proposed to solve this long queue problem using short vehicle trajectories. We first introduce the vehicle trajectory reconstruction model to estimate the missing part in vehicle deceleration or acceleration. The long queue model is then reduced to an ordinary short queue model. A delay-based estimation method is developed to evaluate the cycle-by-cycle queue length. The proposed method is applicable to the moving queue or over-saturation condition, and performs well under low penetration rate. The model is tested in a field experiment with reasonable results.
  Authors: Hao, Peng; Ban, Xuegang (Jeff)
  Authors: Hao, Peng; Ban, Xuegang (Jeff)
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3178
• Self-Organizing Traffic Signals Using Secondary Extension and Dynamic Coordination Rules
  Abstract: Actuated control is very efficient for isolated intersections, but along arterials it lacks the means to synchronize signals, leading to frequent stops. Industry practice in the United States is to use clock-based coordination for arterial control, with signals running with a common cycle and offsets that help ensure good progression. However, clock-based coordination has many drawbacks, among them increased delay for pedestrians, promoting speeding, and a low degree of flexibility for accommodating transit priority. This research proposes a new paradigm for traffic signal control, “self-organizing signals,” that begin with a base of actuated control, but with rules added that can lead signals to synchronize with their neighbors. Rules were developed for secondary extensions to serve an imminently arriving platoon and, for closely spaced intersections, dynamic coordination which forces signals to synchronize with a critical intersection. Simulation tests in two corridors indicate the success of this self-organizing logic, with delay reductions of up to 14% compared to an optimized coordinated-actuated scheme where there is no transit priority. With transit signal priority applied aggressively, transit delay was reduced by more than 10 seconds per train per intersection (more than 50% reduction in transit delay) with almost no impact to traffic.
  Authors: Cesme, Burak; Furth, Peter G.
  Authors: Cesme, Burak; Furth, Peter G.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3197
• Signal Timing Optimization Based on Platoon Segmentation by Using High-Precision Microwave Data
  Abstract: With the development of modern information, communication and connected-vehicle technologies, it is possible to further improve the traffic signal control by using real-time, accurate, and large-scale traffic information. This paper puts forward a new signal timing optimization method based on platoon segmentation by using the high-precision microwave data. An intersection located in the Albany, California is studied as a target intersection. Three microwave sensors are deployed in this intersection which can collect the information of all the moving vehicles in this area every 50 milliseconds. This paper presents the method of platoon segmentation, performance measurement of control delay, control strategies (including green extension, phase termination and double cycle), delay estimation and several application scenarios in detail. Furthermore, by using the actual microwave data and the proposed methods, the paper illustrates the probability density functions of delayed through vehicles, startup and queuing delay etc. Finally, the paper provides the comparative results of control delay by implementing the in-used and proposed three signal timing strategies, which can prove the feasibility and effectiveness of the proposed method.
  Authors: Zhang, Jiajie; Hu, Jianming; Zhou, Kun; Zhang, Wei-Bin
  Authors: Zhang, Jiajie; Hu, Jianming; Zhou, Kun; Zhang, Wei-Bin
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3193
• INCREASING THE CAPACITY OF SIGNALIZED INTERSECTIONS BY DYNAMICALLY USING EXIT-LANES FOR LEFT-TURN TRAFFIC
  Abstract: Many congested intersections have heavy traffic volumes on movements where there is insufficient capacity due to geometric limitations. This paper presented an unconventional approach to increase the capacity of heavily congested intersections: it opens up exit-lanes for left-turn traffic dynamically with the help of an additional traffic light installed at the median opening (the pre-signal), which we shall refer as the exit-lanes for left-turn (EFL) control. Based on this concept, an optimization problem for the EFL was formulated as a Mix-Integer-Non-Linear-Program (MINLP), in which the geometric layout, main-signal timing and pre-signal timing were integrated. The MINLP was solved by transforming it into a series of Mix-Integer- Linear-Programs (MILPs). The latter problem can be solved by the standard branch-and-bound technique. The results of extensive numerical analysis and VISSIM simulation showed that the EFL approach could increase intersection capacity and reduce traffic delay substantially, especially under high left-turn demand. Moreover, the EFL control can be applied to one or multiple arms simultaneously, thus it is particularly useful for intersections with unbalanced left demand and degree of saturation among different travel directions.
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Authors: Zhao, Jing; Ma, Wanjing; Zhang, H. Michael; Yang, Xiaoguang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-2989
• Using High-Resolution Event-Based Detector Data for Traffic Modeling and Control: Overview
  Abstract: Research on the applications of high-resolution event-based detector data for traffic modeling and control is still at very early stage. In this paper, we provide a comprehensive overview on what has been achieved and also think ahead on what could be achieved in the future. It is our opinion that using high-resolution event data, instead of conventional aggregate data, could bring significant improvements to current practices in traffic engineering. Event data records the times when a vehicle arrives at and departs from a loop detector. From that, individual vehicle¡¯s on-time and time gap between two vehicles can be derived. Such detailed information is of great importance for traffic modeling and control. As reviewed in this paper, current research has demonstrated that event data are extremely helpful in the fields of detector error diagnosis, vehicle classification, freeway travel time estimation, arterial performance measure, signal control, traffic safety, traffic flow theory, and environmental studies. In addition, the cost of event data collection is low compared to other data collection techniques. Event data can be directly collected from loop detectors without any changes on the infrastructure, and it can be continuously collected on a 24/7 mode. Since current practices of using event data are still very limited, this brings many research opportunities as suggested in the paper.
  Authors: Wu, Xinkai; Liu, Henry X.
  Authors: Wu, Xinkai; Liu, Henry X.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-4767
• Formulation and Evaluation of Impacts of Switching Control Objectives for Mitigation of Oversaturated Conditions
  Abstract: In Under-saturated conditions, delay minimization and bandwidth maximization are the two main objectives that are used to optimize traffic signals in arterial networks. Targeting one or both of these objectives may not result in effective operations during oversaturated conditions. In order to possibly maintain optimal states of traffic during over-saturated conditions or transitions between unsaturated and over-saturated conditions, control strategies should be developed and formulated based on an integrated criterion that combined throughput maximization, delay minimization and queue management through a multi-objective analysis framework. This paper provides a closed-form formula for the control plan scheduling problem assuming three regimes of operation during an oversaturated control situation: loading, processing, and recovery. The formulation identifies the optimal timing plans for different control objectives in each regime and the optimal point to switch from one plan to the next, which is not typically addressed in traditional signal timing optimization tools. The impacts of switching points on network critical routes travel time were assessed. The simulation results of Post Oak network show significant improvements due to the application of the proposed timing procedure. In particular, the test case also revealed that throughput maximization control during the loading regime provides the network with extra reserve capacities on the critical routes which improves total performance versus other combinations of control objectives.
  Authors: Adam, Zain; Abbas, Montasir M.; Gettman, Douglas
  Authors: Adam, Zain; Abbas, Montasir M.; Gettman, Douglas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-4823
• Approach for Developing Signal Timing Plans to Manage Queues in Oversaturated Arterial Networks
  Abstract: Managing traffic during oversaturated conditions is a challenge for practitioners due to the lack of adequate optimization tools for addressing such situations. Unlike under-saturated conditions, operation of traffic signal systems during congestion requires careful consideration and analysis of the underlying causes of the congestion before developing mitigation strategies. This paper presents an application of a new oversaturation timing strategy (OTS) in a congested arterial network. The OTS employs the principles of oversaturation timing (i.e., prevent spillback into upstream intersections and prevent starvation at downstream intersections in cycle length selection, splits allocations, and offset design along with critical routes protection. Microscopic simulation results of the arterial test case revealed that traffic control strategies developed using the proposed framework led to significant improvement of system performance when compared to signal control strategies designed for operations in under-saturated conditions. Each of the generated control plans includes series of timing plans with different control objectives. These control plans successfully manage the queues along the network links. The developed control plans apply both internal metering by allocating queues on links with extra reserve capacities, and external metering by holding traffic outside the network preventing demand loading on the network from reaching critical levels. It also revealed that applying capacity maximization on early stage would provide extra reserve capacities to the critical routes unlike delay minimization control that balances the queues formations on all network links.
  Authors: Adam, Zain; Abbas, Montasir M.; Gettman, Douglas
  Authors: Adam, Zain; Abbas, Montasir M.; Gettman, Douglas
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-4837
• Arterial Queue Spillback Detection and Signal Control Based on Connected Vehicle Technology
  Abstract: Queue spillbacks are a major problem in urban signalized arterials because they can lead to gridlock and excessive delays. Several methods based on fixed location detector data have been proposed to identify the occurrence of queue spillbacks and implement signal control strategies to mitigate their impacts. We propose the use of Connected Vehicle (CV or probe) data to detect queue spillbacks and respond with alternative signal control settings. The paper presents two queue spillback detection methods. The first one requires only the use of CV data and is based on the notion that non-equipped vehicles in queue after the last CV-equipped vehicle can be modeled using a geometric distribution. The second spillback detection method combines CV data with information about the signal timings at the upstream intersection and is based on kinematic wave theory of traffic. An alternative signal control strategy is activated after a potential queue spillback is detected. The proposed queue spillback detection methods and alternative signal control strategy have been tested through simulation on a four-signal segment of San Pablo Avenue in Berkeley, California. The simulation tests performed identify penetration rate thresholds of CV equipped vehicles for which the proposed methods can accurately detect potential queue spillbacks. In addition, the proposed signal control strategy has been found to improve traffic operations for the upstream cross-streets without compromising traffic operations on either direction of the arterial traffic.
  Authors: Christofa, Eleni; Argote, Juan; Skabardonis, Alexander
  Authors: Christofa, Eleni; Argote, Juan; Skabardonis, Alexander
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-4903
• Decision-Support System for Assessment of Alternative Signal Controllers Using Expert Knowledge Acquisition
  Abstract: The standardization of controller hardware under the Advanced Transportation Controller standard provided the flexibility for customized development of controller software. However, a multitude of controller software features on the market presents a challenge for the assessment when purchasing future system. This paper presents a decision-support application based on Analytic Hierarchy Process technique for the assessment of traffic signal controllers. The method to evaluate the controllers based on the set of criteria derived from market controller features. The application consists of knowledge, model, data, and dialog management components. It was developed in MS Excel, along with supporting MS Access database. The application is highly dependent on the expert knowledge acquisition. It provides weighted Performance Index along with the decision-support visualization aids. The application was developed using previous research originally developed for a signal system under the purview of Virginia Department of Transportation (VDOT). However, the framework and application are transferable among agencies, and can be potentially used for evaluation of other signal infrastructure.
  Authors: Mladenovic, Milos; Abbas, Montasir M.; Gopinath, Sudarshan; Faddoul, Guillaume
  Authors: Mladenovic, Milos; Abbas, Montasir M.; Gopinath, Sudarshan; Faddoul, Guillaume
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-4084
  Practice-Ready: Yes
• Signal Timing Optimization Based on Platoon Segmentation by Using High-Precision Microwave Data
  Authors: Zhang, Jiajie
  Authors: Zhang, Jiajie
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3193
• Evaluation of InSync Adaptive Traffic Signal Control in Microsimulation Environment
  Authors: Stevanovic, Aleksandar
  Authors: Stevanovic, Aleksandar
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-0487
• Self-Organizing Traffic Signals Using Secondary Extension and Dynamic Coordination Rules
  Authors: Cesme, Burak
  Authors: Cesme, Burak
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 430
  Paper Number: 13-3197