Strategies for improved arterial coordination using actuated control

Abstract

Traffic actuated signals have been efficiently used in controlling isolated I intersections because they respond to random traffic fluctuations using detectors on all approaches. Application to coordinated arterial operations is a more complex task and insight into the operational performance of various arterial signal timing strategies is limited. The purposes of this study were to develop a better understanding of the performance of various traffic models providing arterial coordination using actuated control, to determine better ways to use the added flexibility of actuated control in a coordinated system, and to recommend more efficient strategies for coordination using actuated control. Representative traffic control problems were modeled into a statistical testbed using TRAF-NETSIM. A series of scenarios covering a range of arterial geometry, traffic volumes, and traffic actuated control settings were tested. The results indicate that green splits have to be more perfectly tuned in pretimed operation for optimal performance at higher volume levels for a g' en cycle length. At low volumes, any reasonable signal timing strategy works well as long as the detectors work and the traffic signals are coordinated. NETSIM simulation results for pretimed control demonstrate that PASSER 11-90's green splits are optimal and any significant improvement to the arterial is only possible by employing traffic actuated control. It was observed that actuated system performance improved when the arterial's coordinated pretimed phase was reduced from its optimum pretimed value using existing actuated control technology. This finding suggests that a more optimal allocation of arterial green times is possible. Development of an advanced signal controller to implement the recommended control strategy is proposed.