System to Identify Turning Movements at Signalized Intersections

A system to identify all left turns, through movements, and right turns at a signalized intersection is described. The complete system requires detection of vehicle departures from the intersection, right turn detection, and information on present phasing from the signal controller. The system is demonstrated with videotape data for one departure leg of a signalized intersection. Actual vehicle movements are compared to both a manual application of the algorithm and an application using a wide area detection system (WADS). The manual application indicated that the algorithm should correctly reflect vehicle movements. The WADS application also supported the feasibility of the system. The information from such a system could be used to improve the information components of real-time traffic adaptive signal control systems, dynamic traffic assignment, and estimates of origin-destination matrices.