Rational Models for Setting All-Red Clearance, Yellow Clearance,and Green Extension Intervals

This paper reviews the justification for the all-red clearance, yellow clearance, and green extension intervals implemented by Sacramento County in 1998. Traffic signal operational efficiency is enhanced and safe passage is emphasized for drivers using the intersection in accordance with the California Vehicle Code by applying a combination of graphical and numerical methods in a “worst case” scenario analysis. The actual operational performance of this method on crash data history are evaluated and discussed.