Development of Framework for Integrated Dynamic Signal-Variable Speed Traffic Management Algorithm for Signalized Networks

In this paper, the framework of a new traffic management algorithm, which is referred as combined signal-speed control, is presented. The algorithm combines dynamic signal (DS) control with variable speed limit (VSL) selection to obtain near-optimal traffic control solutions for signalized traffic networks. The capabilities of the combined control are explored on grid traffic networks under oversaturated conditions. First a cycle-based macro scope traffic simulation model is formulated. Genetic algorithms (GAs) are employed to obtain near-optimal control solutions for hypothetical traffic networks. Finally the advantages of using combined signal-speed control are accessed. The preliminary results show that: 1) selected speeds result in more efficient offsets, especially for dependent links (on which the offsets are locked to satisfy network closure), 2) queues are managed appropriately throughout the network such that spillbacks are prevented, 3) speed fluctuation on dependent links are larger than that on independent links, and 4) the combined signal-speed control improves the performance of traffic networks compared to dynamic signal controls with fixed speed limit.