Guidelines for Determining Traffic Signal Change and Clearance Intervals
ITE has published guidance on yellow change and red clearance intervals for signalized intersections. The goal of this guidance is to create a consensus methodology for calculating and evaluating traffic signal change intervals that can be consistently implemented by transportation agencies. The recommendations presented should yield reasonable times for the yellow change and red clearance intervals for traffic signals, assisting transportation professionals in enhancing intersection safety, maintaining reasonable traffic flow, and providing for movement of vehicles, bicycles, and pedestrians.
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Current Federal Research Activity
Federal Highway Administration has active research on the topic in the Traffic Signal Change and Clearance Interval Pooled Fund Study, TPF-5(470). Please go to the linked webpage for the most current information on study work.
Additional Information:
Once the FHWA Pooled Fund Study is complete, ITE plans to reconvene a technical committee to review the study results and other research since the publication of the recommended practice to determine next steps regarding this subject matter.
ITE Journal (March 2020) articles:
- Guidelines for Determining Traffic Signal Change and Clearance Intervals – by Douglas E. Noble, P.E., PTOE (F)
- Traffic Signal Change and Clearance Intervals – Research Still Needed! – by Jeffrey A. Lindley, P.E. (F)
- An Explanation of Mats Järlström’s Extended Kinematic Equation – by Jay Beeber
Unpublished material cited in the recommended practice:
- Jay Beeber - Yellow Change Intervals for Turning Movements Using Basic Kinematic Principles
- Mats Jarstrom - An Extended Yellow Change Interval Solution Derived from GHM’s Critical Distance
Webinars: