A Dynamic Programming Model for Bus Signal Priority with Multi requests

摘要

A dynamic programming model has been developed for optimization of bus prioritysignal timings with multi bus priority requests with the objective to minimize theweighted bus delay. The proposed model has the following unique features: (1) theprocess of serve sequence optimization is depicted as a multi stage decision process;(2) explicitly modeling three priority strategies with constrains of minimum greentime, acceptable degree of saturation and length of priority window, and (3) formulatea dynamic programming model which is capable of capturing the impact of busrequests with various occupancy and schedule deviations, and different traffic demandlevel of all approaches, and producing detailed output information including optimalserve sequence of multi bus priority requests and corresponding signal timings.Depending on traffic patterns and different objective, one can change the controlobjective of the proposed model between minimizing weighted bus delay andminimizing the total vehicle delay of bus priority requests. An example shows that afirst-come, first-serve (FCFS) policy for serving priority request can result in moredelay than a multiple priority request policy generated by the dynamic programmingmodel developed in this paper. A rolling horizon scheme was proposed as a futureresearch to enhance the dynamic programming model.