Traffic Signal Timing

There are about 300,000 traffic signals in the United States alone and over 75% of them could be improved by updating equipment or adjusting the timing. Traffic signal retiming is one of the most cost-effective ways to improve traffic movement and make our streets safer. Comprehensive signal retiming programs have documented benefits of 7-13% reduction in overall travel time, 15-37% reduction in delay and a 6-9% fuel savings. 

Signal timing is the process of optimizing the operations of signalized intersections. The objective of signal timing is to respond to the demands of all types of motor vehicles, bicycles and pedestrians in an optimal manner. Signal timing strategies include the minimization of stops and delays, fuel consumption and air pollution emissions and maximizing progression along an arterial. 

Signal timing is only effective as long as the traffic patterns that were used to generate the signal timing remain reasonably similar. However, over time, traffic patterns change. Signal retiming should be reviewed every year to evaluate its effectiveness and to make any changes necessary.

This traffic signal timing e-library is designed to assist practitioners access the wealth of information available on traffic signal timing. 

Signal Timing Resources

FHWA Arterial Management

Traffic Signal Standards

Useful Links

ITS JPO Deployment and Tracking


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