Update of the Traffic Signal Timing Manual

Based on the acknowledged need for consistent national guidance on developing and maintaining effective signal timing, the 2008 <em>Traffic</em> <em>Signal Timing Manual</em> (<em>STM</em>) provided a basic synthesis of signal timing practices in the U.S. The manual covers fundamental signal timing as related to intersection design, vehicle detection, and coordination of signalized intersections. The <em>STM</em> is an important first step, but there are many advanced concepts that need to be addressed in greater detail that are not well documented. These require some research and evaluation to provide substantive direction that will take practice to the next level. The current manual acknowledges some of these in its last chapter, 'Advanced Signal Timing Concepts", discussing traffic signal priority, traffic responsive control, and weather considerations, among others. Improvements due to signal timing are not always quantified because the applications are not always fully documented by before-and-after studies. This is true for topics such as traffic signal priority, emergency vehicle preemption, and special controller functions such as conditional service and simultaneous gap out logic. Despite better detection equipment, microscopic traffic simulation, and signal control logic, associated benefits have not been adequately captured in the literature. The proposed research would incorporate advanced applications and their quantified performance into the <em>STM</em>, moving the industry from current application to state-of-the-art practice. The objective of the research is to develop a guide for advanced signal timing concepts that will expand the scope and depth of the <em>STM</em>. Research and evaluation will be conducted to address the following topics relating to operating traffic signals: detector design, pedestrian treatment, improved coordinated operation, oversaturated conditions, overlaps, and diamond interchanges, plus advanced applications including traffic signal priority, weather impacts, adaptive signal control, and performance monitoring and management. Material developed will be applicable to automobile, truck, bus, bicycle, and pedestrian operations in a signalized arterial environment. The revised guide should consider the pedestrian walking speed requirements of the new Manual on Uniform Traffic Control Devices and present new strategies for accommodating pedestrians at traffic signals. The revised guide should be suitable for publication as an AASHTO guide. Several key issues that need to be considered by the research are: (1) Assessment of non-motorized user needs (pedestrians and bicyclists); (2) Detection designs that maximize versatility in operation, monitoring, and maintenance of the signalized intersections; (3) Effective use of overlaps to facilitate the movement of compatible approaches and movements; (4) Timing diamond interchanges and alternative intersection designs to improve efficiency and safety; (5) Monitoring the performance of signalized intersections; (6) Discussion of new pedestrian/vehicle detection and tracking technologies and their impact on signal timing plans; (7) Use of the controller as a data collection device; (8) Emission-focused policy for signal operations; (9) Surrogates of safety in designing timing plans; (10) Discussion of advanced timing topics: transit focused timing plans, traffic responsive control, adaptive control, and dealing with weather impacts; (11) Railway-highway traffic signal interconnection and design of preemption (physical layout, time/phase plans to assure clear crossing at train arrival); (12) Signal preemption for emergency vehicles (time/phase plans avoiding yellow traps in preemption transition).


  • English


  • Status: Proposed
  • Funding: $600000.00
  • Contract Numbers:

    Project 3-103

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Derr, B

  • Start Date: 20100613
  • Expected Completion Date: 0
  • Actual Completion Date: 0
  • Source Data: RiP Project 26460

Subject/Index Terms

Filing Info

  • Accession Number: 01463927
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 3-103
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:32PM