Left-turn sight distance models for signalized intersections with different configurations

At signalized-intersections where protected left-turn signals are not provided, simultaneous opposing leftturn vehicles attempting the turn maneuver may cause insufficient sight distance for each other. Previous studies had developed sight distance computation models for intersections located on linear major road segments. For more comprehensive and practical application to intersection design, this paper presented a series of left-turn sight distance models to compute left-turn sight distances for different signalizedintersection configurations. They include intersections located on a linear segment, a linear segment but leading a curve one, a curve segment, and a curve segment but leading a linear one. The models can be used to identify a better intersection location along the major road when a curve exists, layout intersection geometric design, or evaluate the sight distance problem of an existing intersection configuration to ensure safe left-turn maneuvers by drivers.