A real-time traffic signal control system: architecture, algorithms, and analysis

The paper discusses a real-time traffic-adaptive signal control system refe rred to as RHODES. The system takes as input detector data for real-time me asurement of traffic flow, and "optimally" controls the flow through the ne twork. The system utilizes a control architecture that (1) decomposes the t raffic control problem into several subproblems that are interconnected in an hierarchical fashion, (2) predicts traffic flows at appropriate resoluti on levels (individual vehicles and platoons) to enable pro-active control, (3) allows various optimization modules for solving the hierarchical subpro blems, and (4) utilizes a data structure and computer/communication approac hes that allow for fast solution of the subproblems, so that each decision can be downloaded in the field appropriately within the given rolling time horizon of the corresponding subproblem. The RHODES architecture, algorithm s, and its analysis are presented. Laboratory test results, based on implem entation of RHODES on simulation models of actual scenarios, illustrate the effectiveness of the system. (C) 2001 Elsevier Science Ltd. All rights res erved.