System Partition Technique to Improve Signal Coordination and Traffic Progression

A heuristic approach to the application of bandwidth-oriented signal timing is proposed based on a system partition technique. The proposed approach divides a large signalized arterial into subsystems with three to five signals in each subsystem. Each subsystem is optimized to achieve the maximum bandwidth efficiency. A one-directional system progression bandwidth, normally in the peak-flow direction, is then formed by appropriately adjusting the offsets between each subsystem. Such an approach provides a signal-timing solution that would achieve maximum progression for the peak direction while still maintaining partial progression for the off-peak direction. Further improvements on signal timing may be achieved by adjusting the phasing sequences at the subsystem boundary locations. A case study is presented to illustrate how the proposed approach can be applied, and the timing solutions are compared with the solutions from traditional signal-timing software. Evaluation of the timing solutions using CORSIM simulation indicates that the proposed approach results in improved bandwidth efficiencies for both directions and improved performance measures such as stops and travel speeds. The proposed heuristic approach is easy to apply using existing signal timing software packages such as PASSER II and Synchro. The proposed approach could also be used to develop new or improved existing bandwidth optimization algorithms.