Task Order 5325
Traffic Operations Research


Development of an Integrated Microscopic Traffic Simulation
and Signal Timing Optimization Tool

Wei-Bin Zhang, Yafeng Yin
California PATH

Heny X. Liu
Civil and Environmental Engineering
Utah State University

Objectives

The study has two objectives:

  1. to integrate Paramics with a signal timing optimization tool to be determined, in order to create a tool to generate, evaluate and fine-tune signal timing plans in a cohesive manner;
  2. to develop a systematic approach to enable the state-of-the-practice closed-loop control systems to be more adaptive to the changes in traffic demands and patterns, making use of real-time traffic and signal data and the integrated tool.
The project will deliver an integrated micro-simulation and signal timing optimization tool that assists traffic operation staffs in optimizing, evaluating and refining signal timing plans for arterial traffic operation. The tool will be user-friendly and easy to use. The research outcome will also include a proof of concept of a systemic approach to make closed-loop control systems be more adaptive in both strategic and tactic levels. The systemic approach includes three components: monitoring, retiming and on-line plan adjustment. The monitoring system will enable traffic operation staffs to understand the historic and current performances of signal control operations and help them make the decision whether a retiming effort is needed or not. The new timing development process developed for a retiming effort will make use of a large set of archived traffic data to produce efficient and timely timing plans for TOD controls. Finally, the on-line plan refiner can marginally adjust certain parameters of the active timing plan, such as added initials and minimal gap, to allow actuated controls to be more adaptively respond to the changes in traffic demands and patterns while maintaining the coordination.

Background

A big segment of the traffic signal control systems in California are closed-loop systems. Because the wide scale deployment of advanced adaptive control systems may be many years away due to the associated high costs, there is a significant need of improving the effectiveness of current closed-loop systems. To address the need, two research directions among others can be adopted. One is to enhance the capability of developing efficient signal timing plans and the other is to enable the state-of-the-practice closed-loop systems to operate in a more traffic-adaptive manner. A fully-integrated micro-simulation and signal timing optimization tool that can efficiently predict traffic condition and optimize signal timing strategies in a cohesive manner will help traffic engineers develop efficient signal timing plans. Paramics is a scalable high-performance microscopic traffic simulation package that has been widely used in Caltrans for years. However, like most simulation tools, it is not designed for traffic operation and thus lacks signal timing optimization capability. Integrating Paramics with a timing optimization program will provide a powerful tool for traffic signal operation. The timing plans can be evaluated and fine-tuned before being implemented in the field. Moreover, the tool can be used for further analyses to study how to develop efficient timing plans.

The advancement and deployment of telecommunication and ITS technologies make real-time (true) traffic and signal status data more readily available. These real-time data provide opportunities to allow closed-loop control systems to operate more adaptively to changes of traffic demands and patterns in both strategic and tactic levels. A large set of archived real-time data will allow traffic engineers to produce a timely and efficient signal timing solution, which makes signal controls to be more adaptive in a strategic level. At the same time, with using real-time traffic and signal status data, online adjustments of the active timing plan will enable actuated controls to respond in a near real-time manner to traffic changes, in other words, to be more adaptive in a tactic level. The above approaches can be evaluated by using the integrated tool to be developed.

Tasks

We plan to carry out the proposed study in a period of one year. The scope of work for the proposed study includes the following tasks:

  • Task 1.1: Review and evaluate signal optimization software and select one to integrate
  • Task 1.2: Develop the integrated tool
  • Task 1.3: Preliminary investigation on tool/Paramics calibration
  • Task 2.1: Develop a signal operation monitoring system
  • Task 2.2: Develop and evaluate an off-line timing development procedure based on archived real-time traffic data
  • Task 2.3: Develop and evaluate an online timing refiner
  • Task 3: Report and documentation writing