In addition to covering basic and advanced signal timing concepts, NCHRP Report 812, Traffic Signal Timing Manual: Second Edition addresses establishment of a signal timing program including setting multimodal operational performance measures and outcomes, determining staffing needs, and monitoring and maintaining the system. Some of the advanced concepts addressed include the systems engineering process; adaptive signal control; preferential treatment (e.g., rail, transit, and emergency vehicles); and timing strategies for oversaturated conditions, special events, and inclement weather. The manual will be useful to traffic engineers and signal technicians at any agency operating traffic signals.

A TRB Webinar on this report has been scheduled for November 4, 2015. Registration information is available at https://www.trb.org/Calendar/Blurbs/172708.aspx

 

In 2008, the FHWA published the Traffic Signal Timing Manual, providing a basic synthesis of signal timing practices in the United States. The manual covered fundamental signal timing related to intersection design, vehicle detection, and coordination of signalized intersections; but there were many concepts that, due to resource constraints, were not addressed in great detail. Under NCHRP Project 03-103, Kittelson and Associates expanded and upgraded this manual, addressing many of the shortcomings.

 

Several goals guided the development of the manual: (1) provide material useful to agencies in documenting their own signal timing policies and practices, (2) facilitate the training of new staff, (3) facilitate implementation of more advanced signal timing concepts where appropriate, (4) include examples that illustrate application of the manual material to real-world intersections and systems, and (5) include references that promote a fuller understanding of topics.

 

During the course of the project, the research team reviewed the pertinent literature (including agency signal timing manuals) and conducted four multi-agency focus groups and a workshop to get feedback on the utility of the 2008 Traffic Signal Timing Manual to typical users. From these efforts, the team identified topics that should be expanded or deepened. The user feedback also greatly influenced the organization of the second edition of the manual to increase its usefulness to practitioners.