Development of Left-Turn Lane Guidelines for Signalized and Unsignalized Intersections;Final rept. Sep 01-Dec 03

摘要

It is generally accepted that the level of service (LOS) at intersections significantly affects the overall LOS of the road system. It is also known that LOS at an intersection can be adversely affected by frequently allowing left-turning vehicles to block through traffic. In addition, crash rates tend to be higher at intersections than on through sections of a road. The separation of left-turning vehicles from through traffic is therefore an important condition for the safe and effective operation of intersections. Existing guidelines for installing left-turn lanes have several limitations. They are mainly based on the traffic volumes at the intersection, and they use deterministic models with fixed gap acceptance and/or left-turn maneuver times. In addition, the guidelines for left-turn lanes for unsignalized intersections and signalized intersections must be specific for the type of intersection.