Development and Evaluation of an Adaptive Transit S ignal Priority Control with Updated Transit Delay Model

摘要

Transit Signal Priority (TSP) strategies are widely used to reduce bus travel delay and increasebus service reliability. State-of-the-art TSP strategies enable dynamic (and optimal), rather thanpredetermined, TSP plans to reflect real-time traffic conditions. These dynamic TSP plans arecalled adaptive TSP. Existing adaptive TSP strategies normally use a performance index (PI),which is a weighted summation of all types of delays, to evaluate each candidate TSP plan andthe weights to reflect the corresponding priority. The performance of adaptive TSP depends onthree factors: delay estimation, weights determination and optimization formulation. In thiscontext, there are three key academic contributions of this paper: 1. enhance an advance detection-based bus delay estimation model; 2. develop a mechanism to dynamically adjust thePI weights to reflect the changing necessity of TSP under different conditions; and 3. formulatethe TSP optimization into a quadratic programming problem with an enhanced delay-based PI toobtain global optimization using MATLAB solvers. In addition, an adaptive TSP simulationplatform was developed using a full-scale signal simulator, ASC/3, in VISSIM. The optimal TSPplans are granted or rejected based on TSP events, such as check-in, check-out and multiple TSPrequests. Through a case study in VISSIM, it was found that, compared with conventional activeTSP strategies, the new adaptive TSP strategy could further reduce bus travel time, whilemaintaining a better balance of service on non-TSP approaches along a 7.4 kilometre buscorridor in Edmonton, Alberta, Canada.