Pedestrian safety guidelines and proposed left-turn phase warrant.

For intersections with a permissive or protected-permissive left-turn mode, pedestrians cross during the permissive period. This operation requires the left-turn driver to yield to both opposing vehicles and pedestrians, prior to accepting a gap and completing the turn. Pedestrian crash risks are increased in these complicated driving conditions because left-turn drivers sometimes fail to yield to pedestrians. Guidelines for the selection of left-turn mode (e.g., permissive, protected, and protected-permissive) focus mainly on vehicular traffic conditions at the intersection. Very few of these guidelines include a sensitivity to pedestrian volume or other pedestrian-safety-related factors. This report provides guidelines for determining whether protected left-turn operation is appropriate based on consideration of pedestrian safety and vehicle operation. These considerations include the road-user costs associated with pedestrian-vehicle crashes and vehicle delay. The report also describes a proposed warrant for left-turn phase determination that is based on the guidelines. (Author/publisher)