Bus Preemption Signal (BPS): An Application of an Advanced Public TransportationSystem (APTS)

摘要

With the emergence of Intelligent Transportation System (TTS) technologies, therehas been a renewed interest in the bus priority signal (BPS). However, at present there is no model capable of simulating various BPS strategies and then restoring the original signal settings after bus preemption is awarded. The effect of providing the BPS treatment on the Washtenaw Avenue Corridor in Ann Arbor, Michigan was studied. The NETSIM graphic animation feature was used to detect bus arrival, award preemption, and the signal timing plan was restored to the original signal setting manually. The model was calibrated using field data and the sensitivity of the model to several variables was tested. The BPS was tested under different network traffic volumes, different main to cross street traffic ratios for an isolated intersection, and signal preemption for carpools. It was found that maintaining progression is most critical under heavy traffic conditions. The traffic volume criteria that warrant signal preemption were established. There appears to be advantages to providing carpools with preemption capability up to between 5 and 10% of the main street traffic volume. In any corridor there is likely to be random fluctuations in the traffic demand, and this variation may be as large as the measured effect of BPS.