A METHODOLOGY FOR OBTAINING SIGNAL COORDINATION WITHIN A DISTRIBUTED REAL-TIME NETWORK SIGNAL CONTROL SYSTEM WITH TRANSIT PRIORITY

Real-time network signal controls offer the potential to provide delay benefits over traditional fixed time and actuated control. The SPPORT (Signal Priority Procedure for Optimization in Real-Time) model is a fully distributed heuristic rule-based signal control method that explicitly considers transit priority. While a distributed architecture enables the network control problem to be decomposed in such way that local controllers can optimize individual intersections it also prevents the explicit development of coordination along signalized corridors. In this case, coordination can only be achieved when local controllers are instructed to consider the timing plans of adjacent controllers, the vehicle departures from upstream adjacent intersections, and the projected vehicle arrivals at downstream adjacent intersections. This paper describes a coordination methodology that was developed for use within the SPPORT model to allow it consider traffic progression objectives. In this methodology specific considerations are given to coordination with downstream signal timings, downstream queues, downstream transit activities upstream signal timings, upstream queue spillback events, and upstream transit activities. An evaluation of the resulting model for a five- intersection arterial corridor with scenarios considering a range of traffic conditions finally shows the benefits that the application of the model can provide, particularly over fixed-time control