Improving intersection performance with left turn phase reservice strategies

Advanced signal operations offer practitioners an opportunity to reduce delay at their intersections at minimal cost by using features already included in their signal control software. One advanced operations technique is phase reservice and its associated feature conditional reservice. This research examines the impact of applying these techniques to the left turn at Hall Blvd. on 99W in Tigard, OR. Significant delay savings were seen for the left turn movement with an average delay reduction of more than 30 seconds at the cost of approximately 3 seconds increased delay for the opposing through movement. Intersection delay reduction was found to be dependent on the ratio of left turning vehicles to opposing through traffic.