Traffic Signal Change Intervals Recommended Practice
The Institute of Transportation Engineers (ITE) is in the process of preparing Guidelines for Determining Traffic Signal Change Intervals a Recommended Practice (RP). In 1985 ITE published a Proposed Recommended Practice entitled Determining Vehicle Change Intervals that was not ratified to become an RP. Later, in 2001, ITE published the informational report A History of the Yellow and All-Red Intervals for Traffic Signals. In the interim, changes in technology, automated enforcement, the availability of new primary data, further research and the public and professional concern that a defined standard of reference does not exist with regard to this topic have led to the initiative to develop this RP.
ITE plans to prepare the RP to reflect the current state-of-the-practice and to provide the user with a broader overview of key considerations to determine yellow change and red clearance intervals for traffic signals and their application. A separate effort is underway by the National Cooperative Highway Research Program (NCHRP) to prepare a document entitled Guidelines for Timing Yellow and All-Red Intervals at Traffic Signals. This project will have a longer time horizon because it will incorporate new primary data into the research.
