Online turning proportion estimation in real-time traffic-adaptive signal control

An online method for traffic-adaptive turning proportion estimation for intersections based on a least-squares minimization approach is presented. It assumes that entering-vehicle lane counts and exiting-vehicle counts during every traffic signal phase and in each direction of an intersection are available. Estimations based on field data in the last three cycles (approximately 5 min) are compared with actual values. This method of turning proportion estimation was also implemented within RHODES, a real-time traffic-adaptive signal control system developed in the Advanced Transportation and Logistics; Algorithm and Systems Research Center at the University of Arizona. The resulting system was evaluated in a laboratory using CORSIM, a microscopic traffic simulation computer package. Performance of RHODES improves when the online traffic-adaptive turning proportions are used instead of constant turning proportions.