GUIDELINES FOR EXCLUSIVE/PERMISSIVE LEFT-TURN SIGNAL PHASING. FINAL REPORT

The objective of this research was to develop guidelines for the use of exclusive/permissive left-turn signal phasing. This was achieved by collecting data on traffic and roadway conditions for exclusive, exclusive/permissive, and permissive left-turn phasings and then analyzing the data to identify relationships between the left-turn phasings and traffic and roadway conditions. The guidelines addressed the following: (1) volume guidelines based on peak hour minimum left-turn volume and the product of the peak hour left-turn and opposing volumes, (2) annual left-turn accident experience, (3) left-turn traffic conflict experience based on critical number and rates, (4) left-turn delay, and (5) site condition factors identified in the study.