2013 Session: 496

• Toward Smart Intersections for Urban Travelers on Sustainable Modes:Better Service via Real-Time Sensing
  Abstract: Sustainability has emerged as a social goal for transportation to pursue by making a change, and transpor-tation engineering should be aimed to increase the level of walking and pedalcycling travels to advocate “New Urbanism and Smart Growth”. More walkable communities are believed more beneficial to the moving public and the sustainability of multimodal transportation systems. Walking and pedalcycling modes promote healthy living style and possess sustainable advantages over the motorized modes in man-ifold aspects. Moreover, the increase in walking and pedalcycling travels fosters the ridership level of public transportation systems. Hence, to boost advancements in pedestrian-/pedalcycle-related infrastruc-ture is essential to bettering transportation sustainability in real-world practice.This research innovatively realized a system prototype which improves non-motorized traveler service at typical urban intersections, in order to resolve the problem that the existing signal timing stand-ard cannot offer friendly accommodation and adequate safety for waiting and crossing pedestrians and/or pedalcyclists. The new system resorts to the real-time sensing concept to smartly adjust signal displays to ensure that waiting pedestrians and/or pedalcyclists are released in a responsive manner and crossing ones are safely protected by signals. In simulation tests, this research quantified the benefits from the new sys-tem in comparison with its original counterpart. Simulation experiments unveiled a current timing safety countermeasure is deficient for mobility efficiency. In contrast, the new functions smartly serves for all non-motorized travelers with friendly accommodation and adequate safety, while maintaining good mobility efficiency for motorized travelers.
  Authors: Lu, George; Noyce, David A.
  Authors: Lu, George; Noyce, David A.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0478
• Evaluation of Different Bus Priority Functions in Coordinated Traffic Signals
  Abstract: Delay at signalized intersections is a considerable part of the journey time for public transport (PT) in urban areas, but the delay can be reduced with PT priority in the signals at a relatively low cost to other traffic. The impact on other traffic is dependent on what priority functions are used, but the effects are hard to calculate in a coordinated system and do not always act intuitively. In this paper are experiments with a microscopic traffic simulation model and a software-in-the-loop signal controller simulator conducted to study the costs and benefits, primary in terms of travel times, for busses and other traffic of different priority functions in the Swedish PRIBUSS method for conditional active bus priority. Based on the analysis of the different functions are new conditions for priority proposed and tested with simulations.
  Authors: Wahlstedt, Johan
  Authors: Wahlstedt, Johan
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0818
• Development of Degree-of-Priority Based Preemption Control Strategy for Emergency Vehicle Operation
  Abstract: This paper proposes a degree-of-priority based preemption control strategy for emergency vehicle operation to decrease the impacts of emergency vehicles on normal traffic. The proposed model features its effectiveness to following three aspects: (1) a multilayer fuzzy model was established to determine the degree-of-priority based on emergency vehicle preemption demand intensity and preemption control influence intensity; (2) for emergency vehicles with proper classification, a travel time estimation model for emergency traffic was formulated, and an optimal emergency route determine model based on the level of priority of emergency events and the emergency vehicle travel time was developed to minimize evacuation time as well as minimize the adverse impacts of preemption on normal traffic; and (3) a conditional traffic signals priority control method at each intersection of the evacuation route was built, so that traffic queue at each intersection can be cleared previous the arrival of emergency vehicles. A simulation model based on field data was developed, and the performance of the proposed strategy was compared with the conventional local-detection based method under the microscopic simulation model. The results validated the efficiency of the proposed strategy in terms of minimizing the delay of emergency vehicles and reducing adverse impacts on normal traffic.
  Authors: Wang, Jiawen; Yang, Xiaoguang; Ma, Wanjing
  Authors: Wang, Jiawen; Yang, Xiaoguang; Ma, Wanjing
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-1891
• Reinforcement Learning-Based Signal Control Using R-Markov Average Reward Technique Accounting for Neighborhood Congestion Information Sharing
  Abstract: This research proposes and implements a reinforcement learning (RL) based signal control using R-Markov Average Reward Technique (RMART) accounting for neighborhood congestion information sharing. The algorithm is implemented and tested at network level in a traffic simulation tool (VISSIM) using the COM interface. The comparison with traditional Q-learning and SARSA algorithms indicate that RMART performs better at higher congestion level. Different reward functions are tested with the algorithms at different congestion level. Further, a multi-reward structure for RL is proposed that dynamically adjusts the reward with varying congestion state at the intersection.
  Authors: Aziz, H. M. Abdul; Ukkusuri, Satish V.; Feng, Zhu
  Authors: Aziz, H. M. Abdul; Ukkusuri, Satish V.; Feng, Zhu
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3227
• New Methodology for Systemwide Intersection Signal Timing Optimization Simultaneously Minimizing Vehicle and Pedestrian Delays
  Abstract: This study introduces a new methodology for systemwide intersection signal timing optimization that is carried out by adjusting green, yellow, and red splits for all signalized intersections in the network for AM peak, PM peak, and rest of the day periods without changing the cycle length and signal coordination to achieve the lowest level of vehicle and pedestrian delays per cycle over a 24-hour period. The proposed methodology contains a basic model that handles vehicle delays only and an enhanced model that simultaneously deals with vehicle and pedestrian delays, respectively. Both models are incorporated into a simulation-based model that could conduct regional traffic assignments on a second-by-second basis and applied using data on Chicago regional travel demand, field vehicular and pedestrian traffic counts, geometric designs, and traffic control particularly traffic signal timing plans for intersections in Chicago Central Business District (CBD) street network. The computational experiment reveals that vehicle delay reductions in Chicago CBD could reach 10 percent by minimizing vehicle delays only for signal optimization and 3-5 percent by jointly minimizing vehicle and pedestrian delays for signal optimization. The computational results could be further related to specific traffic signal coordination strategies for different study areas to determine desirable changes in field deployed cycle lengths, splits, and coordination to reduce delays and congestion.
  Authors: Roshandeh, Arash M.; Levinson, Herbert S.; Li, Zongzhi; Patel, Harshingar; Zhou, Bei
  Authors: Roshandeh, Arash M.; Levinson, Herbert S.; Li, Zongzhi; Patel, Harshingar; Zhou, Bei
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3391
• Effective Coordinated Optimization Model for Transit Priority Control Under Arterial Progression
  Abstract: Aiming at providing effective priority control for transit as well as minimizing the adverse impacts on passenger car movements along the arterial, this paper presents an effective coordinated transit priority control optimization model which has the following features: (1) the control unit is defined as the coordinated intersection group between two successive bus stops; (2) buses are detected after leaving the upstream stop before their arrival at the first intersection of a control unit; (3) the dynamic interactions of priority strategies between adjacent intersections within a control unit are modeled using a bus delay model and an ineffective priority time model; (4) a linear program model is developed to generate the optimal priority strategies to reduce the bus travel time in case of priority is necessary and ensure every priority treatments implemented at each intersection is effective. Extensive experimental analyses, including time-space diagram based deterministic analysis and simulation based analysis were performed, and results were compared with the conventional transit signal priority strategy and no priority scenario. The proposed model presents promising outcomes in design of transit priority control signals in terms of decreasing bus delay, improving bus schedule adherence, and minimizing negative impacts on general traffic under different traffic demand patterns.
  Authors: Zhao, Jing; Ma, Wanjing; Head, Larry
  Authors: Zhao, Jing; Ma, Wanjing; Head, Larry
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3006
• Transit Priority Strategies for Multiple Routes Under Headway-Based Operations
  Abstract: This paper presents a transit signal priority (TSP) model designed to maximize the benefits of both bus riders and all intersection passenger car users. The proposed strategy, mainly for headway-based bus service, offers the responsible agency a reliable way to determine the extended green duration in response to multiple bus priority requests for different routes. Depending on the focus of applications, one can select a different control objective for different times of a day with our proposed TSP control logic. Using the field data from Jinan, China, the proposed strategy has shown its promise in reducing the bus passenger waiting time and the total intersection delay. Our further exploration with simulation experiments for sensitivity analysis has also found that TSP will be most effective if the ratio between bus and passenger volumes exceeds some threshold.
  Authors: Lin, Yongjie; Yang, Xianfeng; Chang, Gang-Len; Zou, Nan
  Authors: Lin, Yongjie; Yang, Xianfeng; Chang, Gang-Len; Zou, Nan
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3190
• Simultaneous Optimization of Signal Timings, Departure Time, and Dynamic Speed for Bus Priority Operations
  Abstract: Most previous works of transit signal priority merely focus on optimization of signal timings. Bus speed and dwell time at bus stop are used as exogenous inputs. This paper presents a novel approach for integrated optimization of bus holding time at bus stop, signal timings, and bus speed to provide priority to buses at isolated intersections. The objective of the proposed model is to minimize the total intersection cost that includes bus delay and the impact on the overall traf?c near the intersection in the meantime, to the maximum extent possible, ensure bus clearing the intersection without stop by the red light. A set of formulations are developed to capture explicitly the interaction between bus speed, bus holding time and transit priority signal timings. Experimental analyses have shown that the proposed integrated operational model outperforms the no priority, signal priority only, and signal priority with holding control strategies (no bus speed adjustment) in terms of reducing average bus delays and stops, and only causes little acceptable negative impacts on general traffic. The sensitivity analysis has further demonstrated the potential of the proposed approach to be applied in real-time bus priority control system under different levels of traffic demand.
  Authors: Wu, Wei; Ma, Wanjing; Yang, Xiaoguang
  Authors: Wu, Wei; Ma, Wanjing; Yang, Xiaoguang
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3537
• Testing Strategies to Reduce Pedestrian Delay at Signalized Intersections: Pilot Study in Portland, Oregon
  Abstract: Recently, walking has gained attention as an environmentally and economically sustainable transportation mode. While, the increased focus on pedestrians has led to infrastructure and safety related improvements, little attention has been paid to optimizing the transportation system for their benefit. This paper summarizes the findings of a pilot study that was designed to explore strategies for reducing pedestrian delay at signalized intersections. The two chosen study locations included one half-signal and a full signalized intersection in Portland, Oregon. While the objective of these strategies was to enable the traffic signal to be more responsive to pedestrian needs, the broader objective is to develop settings that can be used at other locations. Changes to signal timing parameters such as the mode of signal operation and the permissive length were studied at the two locations, and the resulting effects on pedestrian delay were quantified. Setting a coordinated signal free during the off-peak traffic periods and increasing the permissive length have both resulted in decreasing pedestrian delay. The techniques described in this paper are also applicable for signalized intersections where low volume side streets intersect high volume major arterials. The findings from this study will also inform practitioners in determining treatments that are consistent with the policies of their agency.
  Authors: Kothuri, Sirisha Murthy; Reynolds, Titus; Monsere, Christopher M.; Koonce, Peter J .V.
  Authors: Kothuri, Sirisha Murthy; Reynolds, Titus; Monsere, Christopher M.; Koonce, Peter J .V.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3854
• Statistical Study of Impacts of SCATS Adaptive Traffic Signal Control on Traffic and Transit Performance
  Abstract: SCATS adaptive traffic system control is designed to improve mobility on congested corridors with variable demand but not as a tool to improve transit performance. However, many urban corridors are heavily used by transit routes. Hence, it is important to determine how SCATS affects transit performance on heavily used transit corridors. This research presents the first joint evaluation of SCATS and TSP (transit signal priority). The case study is based on before and after traffic and transit data along Powell Boulevard, one of the most congested urban arterial in the Portland, Oregon, metropolitan region. Utilizing permanent traffic data collection stations, bus automated vehicle location (AVL) and automatic passenger count (APC) data, and transit signal priority request, this work presents the results of statistical tests and regressions to determine SCATS impacts. Statistically significant differences were observed in terms of travel times and SCATS related regression parameters. Overall, the travel time changes or improvements related to SCATS seem to depend greatly on the direction of travel and the time of day.
  Authors: Slavin, Courtney; Feng, Wei; Figliozzi, Miguel; Koonce, Peter J .V.
  Authors: Slavin, Courtney; Feng, Wei; Figliozzi, Miguel; Koonce, Peter J .V.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-4570
• Optimal Speed Trajectory for Fuel Consumption Reduction at Signalized Intersection
  Abstract: Optimal speed trajectory is a critical input for reducing vehicle fuel consumption and greenhouse gas emission. In this study, we formulate optimal speed trajectories at signalized intersection as solutions to a multi-stage optimal control problem, which considers the impacts from vehicle queues due to traffic lights. After investigating the multi-stage optimal control problem, we further propose an alternative optimization formulation as an approximation approach, which has a smaller problem size and can be solved quickly. We demonstrate the effectiveness of the proposed model and the efficiency of the optimization approach by a numerical example.
  Authors: He, Xiaozheng; Liu, Henry X.
  Authors: He, Xiaozheng; Liu, Henry X.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-5179
• A Performance Diagnosis Tool for Arterial Traffic Signal
  Abstract: Efficient traffic signal operation is greatly beneficial to road users. Due to the intensive labor required, even though traffic signal retiming has a very high benefit/cost ratio, most of the traffic signals in the US are retimed once every 3-5 years or longer. Such practice may miss the opportunities for operational improvements and lead to unnecessary delays. One of the major obstacles is the limited capability of data collection and a lack of convenient performance monitoring tools for signalized arterials. To make up for this limitation, this paper proposed a performance diagnosis tool for arterial traffic signal system. The tool aims at identifying necessary parameter changes and assisting agency to automatically fine tune the traffic signal system. A flexible and low cost data collection unit (DCU) is developed for the tool to enhance traffic signal cabinets with event-based data collection capability. Three major parameters of traffic signals, offset, green split and cycle length, are then evaluated in the data center via diagnosis modules utilizing event-based traffic data. The development of DCU as well as the diagnosis methodologies is described in details in this paper. The implementation of the tool is illustrated by field data analysis at intersections on Minnesota Trunk Highway (TH) 13 in Savage, MN.
  Authors: Zheng, Jianfeng; Liu, Henry X.; Misgen, Steve; Yu, Guizhen
  Authors: Zheng, Jianfeng; Liu, Henry X.; Misgen, Steve; Yu, Guizhen
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-5231
• Effects of Queue Jumpers and Transit Signal Priority on Bus Rapid Transit
  Abstract: Preferential treatments for transit are needed for high-occupancy transit vehicles to improve their operations. However, these treatments are often not effective in saturated traffic conditions when transit operates in mixed traffic. Additional Right-of-Way (ROW) for transit at intersections can be achieved with Queue Jumpers. They allow buses to bypass the waiting queues by using queue jumper lanes and getting an early green signal. The goal of this paper is to evaluate individual and combined effects of Queue Jumpers and Transit Signal Priority (TSP) on performance of a Bus Rapid Transit (BRT) system and vehicular traffic along 3500 S in West Valley City, Utah. Four VISSIM microsimulation models were developed for evaluation: the existing scenario without special treatments for transit (Base), the QJ scenario that introduced Queue Jumpers only, the TSP scenario that implemented TSP only, and a combination of Queue Jumpers and TSP (QJ & TSP). The implementation of any transit strategy resulted in significant improvements in BRT operations. The QJ & TSP scenario yielded highest benefits: 13-22% reduction in BRT travel times, better corridor progression, lower intersection delays and number of stops, increased speed (22%), and better travel time reliability and headway adherence. Transit treatments did not affect private traffic along the corridor. These strategies, however, had certain impacts on side streets. QJ & TSP scenario increased average delays for cross-street traffic by 15%. However, with small improvements in QJ and TSP settings, the combination of the two strategies can be most beneficial and highly desirable for implementation.
  Authors: Reza, Zahid; Zlatkovic, Milan; Stevanovic, Aleksandar
  Authors: Reza, Zahid; Zlatkovic, Milan; Stevanovic, Aleksandar
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0483
  Practice-Ready: Yes
• Midtown in Motion: New Active Traffic Management Methodology and Its Implementation in New York City
  Abstract: This paper summarizes a new active traffic management methodology developed and deployed in New York City. The design, development and implementation of the methodology are driven by the availability of extensive real-time travel time data, the upgraded ITS infrastructure and the need of a reliable and robust real-time signal control system for congestion management in a complex urban traffic environment. The primary objective is to maintain mobility in the subject control zone by preserving capacity and avoiding breakdown within the zone. To that end, multi-regime adaptive signal control strategies, ranging from strategically regulating traffic demand to balancing queue-storage ratio at critical intersections, work in concert to proactively manage congestion. Large-scale real-time travel time data (nearly 1 million records of individual trips per day) are utilized for effective control. This renders the system perhaps the first large-scale active traffic management framework that uses travel-time based adaptive control for congestion management in an urban grid network. In addition to running autonomously, a new mode of operator-in-the-loop allows the operators to interact with important signal timing decisions when the traffic pattern changes abruptly or switch of control policies is involved. The system has been deployed in a congested urban central business district in Manhattan, New York City. The initial deployment, called ¡°Midtown-in-Motion¡±, includes a core 110 square block zone of Midtown Manhattan, from 2nd Avenue to 6th Avenue, and from 42nd to 57th Streets. New expansion is currently underway, covering more than 270 square blocks of Midtown Manhattan, from 1st to 9th Avenue, and from 42th to 57th Street.
  Authors: Xin, Wuping; Chang, Jinil; Muthuswamy, Satya; Talas, Mohamad A.
  Authors: Xin, Wuping; Chang, Jinil; Muthuswamy, Satya; Talas, Mohamad A.
  Year: 2013
  Document Type: Paper
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-4145
  Practice-Ready: Yes
• Development of Degree-of-Priority Based Preemption Control Strategy for Emergency Vehicle Operation
  Authors: Wang, Jiawen
  Authors: Wang, Jiawen
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-1891
• Transit Priority Strategies for Multiple Routes Under Headway-Based Operations
  Authors: Lin, Yongjie
  Authors: Lin, Yongjie
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3190
• Midtown in Motion: New Active Traffic Management Methodology and Its Implementation in New York City
  Authors: Xin, Wuping
  Authors: Xin, Wuping
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-4145
• Statistical Study of Impacts of SCATS Adaptive Traffic Signal Control on Traffic and Transit Performance
  Authors: Feng, Wei
  Authors: Feng, Wei
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-4570
• A Performance Diagnosis Tool for Arterial Traffic Signal
  Authors: Zheng, Jianfeng
  Authors: Zheng, Jianfeng
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-5231
• Effects of Queue Jumpers and Transit Signal Priority on Bus Rapid Transit
  Authors: Zlatkovic, Milan
  Authors: Zlatkovic, Milan
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0483
• Effects of Queue Jumpers and Transit Signal Priority on Bus Rapid Transit
  Authors: Stevanovic, Aleksandar
  Authors: Stevanovic, Aleksandar
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-0483
• Optimal Speed Trajectory for Fuel Consumption Reduction at Signalized Intersection
  Authors: He, Xiaozheng
  Authors: He, Xiaozheng
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-5179
• Simultaneous Optimization of Signal Timings, Departure Time, and Dynamic Speed for Bus Priority Operations
  Authors: Wu, Wei
  Authors: Wu, Wei
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Operations and Traffic Management
  Session: 496
  Paper Number: 13-3537