Signal timing plays a significant role in moving people through transportation networks. It is used in the field to control different movements and modes and is often evaluated as part of planning efforts in the analysis of different scenarios. For those new to traffic signal timing or even the field of transportation, there are resources to learn about the complex interactions within traffic signal systems.


This NCHRP project developed a guidebook that explains traffic signals from the ground up. The Signal Timing Manual starts at the most basic level to explain how detection and displays interact with a traffic signal controller, and each chapter builds upon the previous one. The document includes reference material on traffic signal design elements, intersection/uncoordinated timing, system/coordinated timing, and various advanced applications.



The Outcome

A Primer on Traffic Signal Timing

Kittelson worked with a large team to produce the second edition of the Signal Timing Manual. The second edition refines material from the first edition, adds four new chapters for more advanced users, and expands the use of graphics throughout the document. It is available at no cost at




Transportation Research Board, National Academy of Sciences


Washington DC