Study On Intersection Signal Priority Control Technology For BRT

With the increasing growth of China’s economy and the private car ownership in China, China’s urban congestion problems in big cities are becoming more and more serious. BRT system as a kind of high efficiency, low cost, large capacity transportation is becoming more and more popular with the city traffic planners. At present, from the view of the operation of BRT system in big cities, BRT system has established a set of complete equipment system (including the lanes, BRT stations, BRT vehicles, charging system, etc.), which does not reflect the priority of BRT, especially reflect the BRT bus’priority in signal intersection and apply some priority control methods and technology.This paper aimed at the priority control problems in the BRT multiphase signalized intersections, on the basis of the traditional Webster signal timing method, three kinds of timing optimization models were proposed, the uniform arrival optimization timing model, HCM2000optimization timing model and Webster optimization timing model. These three optimization timing models used minimum value of the entire signalized intersection average vehicle delay function as the objective function, and used the maximum cycle, the minimum cycle, the maximum green time, the minimum green time, and the maximum saturation as constraint conditions, established BRT signalized intersection signal optimization timing model, and used the fmincon function in Matlab which can solve constraint optimization problems to solve the models. Then, through the example of a BRT signalized intersection, used the average vehicle delay、the average passenger delay and the average BRT passenger delay of the entire BRT intersection as the evaluation parameters to prove the validation of these three timing optimization models. Assuming uniformly distributed vehicle input on every direction under saturated flow condition, the delay impact of early green and extended green to BRT phase, non-priority phase and whole intersection, and signal timing adjustive conditions of BRT signal priority were analysed and three conditions of signal timing adjustment were summarised, then a model reflecting the whole intersection’s delay change of early green and extended green was established. Finally provided a combined control strategy of the hysteresis station scheduling control、early green control and extended green control.