Overview
This report provides comprehensive and uniform guidelines for safe and efficient yellow change and all-red clearance intervals at signalized intersections. The project (1) reviewed and compared the definitions of yellow change and all-red clearance intervals,(2) conducted a critical review of relevant available literature, (3) conducted a survey of yellow and all-red timing practices at public agencies, and (4) reviewed past studies and agency operational experiences in relating change interval timing to red-light running and crashes. This information was synthesized to identify key stakeholder groups, point out knowledge gaps encountered in the research, and produce a draft outline of the guidelines. The project conducted field studies on critical factors including reaction time, deceleration rates, and the impact of the other factors identified as important in the design of change intervals. This information was analyzed to develop yellow change and all-red clearance interval guidelines, which provide a framework that can be easily applied by state and local transportation agencies.