Real-time Queue Length Estimation of Signalized Intersections Based on RFID Data

flow to estimate queue length in real-time at signalized intersection is a long-standing problem. The traditional input output approach for queue length estimation can only handle queues that are shorter than the distance between vehicle detector and intersection stop line, because cumulative vehicle count for arrival traffic is not available once the detector is occupied by the queue. Based on the analysis of traffic flow's shockwave profile on the approach of signalized intersections, the paper brings forward a model to detect the real-time queue length based on RFID detector data. The model solves the problem of measuring intersection queue length by exploiting the queue delay of individual vehicles instead of counting arrival traffic flow in the signal cycle. Variations of the estimation model are also presented under different traftic volumes, the relationship between queue length and the capacity of the approach is also under consideration. A field experiment using RFID Detector Data was conducted at an intersection in Nanjing. The results of field experiment demonstrate that the proposed models can estimate the real-time queue length with satisfactory accuracy. (C) 2013 lite Authors. Published by Elsevier Ltd.