Transit Signal Priority Control Strategy And Microscopic Simulation Research Considering Vehicle Exhaust Emission Factor

ABSTRACT:With the development of economy and the rapidly rising of car ownership, motor vehicle exhaust emission has become one of the main sources of air pollution in cities. In addition, because of the signal control at the intersection, acceleration, deceleration and idling conditions of vehicle have significantly increased. This caused the intersections became the high emission and high energy consumption areas in the road network. In order to implement the "bus priority" development strategy and reduce motor vehicle exhaust emission in the intersection area, it is imperative to improve the transit signal priority measures.In this context, the research has analyzed a large amount of emissions data accessed through motor vehicle bench test, and found out the vehicle emissions under different driving conditions. Based on this, this paper presented a transit signal priority strategy considering the vehicle exhaust emission factor, with maximum comprehensive benefit as the goal. At last, the research implemented this transit signal priority strategy using VISSIM simulation, which shows that the transit signal priority strategy presented in this paper could reduce the passengers’time loss and additional emissions, while the benefits of overall intersection did not lose so much, comparing with the fixed signal control. The research in the dissertation consists of the following accomplishments:1. Optimized the acceleration constant and inertia weight in the particle swarm optimization. Compared with the original PSO, this paper added two optimized formulas, so that the acceleration constant and inertia weight could change with the iterations. At last, the research has written an optimized PSO program in Matlab and improved the accuracy and convergence rate through the research on the thresholds of the optimized formulas.2. This paper modeled the transit signal priority strategy considering the vehicle exhaust emission factor. This model could evaluate a transit signal priority strategy using the performance index function, which includes the passenger time performance index function and environment performance index function. The research on this model shows that the passenger time benefit and environment benefit will be reduced with the increasing of green time of priority interface, and the decline of these benefits will become bigger after the first green time compression interface reaches the limit compression time. 3. Zhongguancun Road and Zhichun Road intersection in Beijing was taken as a case study. A VISSIM based traffic simulation platform is used. After using Matlab and optimized PSO to calculate the optimal signal timing for different priority situations, VisVAP has been used to write the program of transit signal priority strategy. Based on this, the transit priority strategy presented in this paper could be simulated in VISSIM. The simulation result shows that the transit priority strategy presented in this paper could not only reduce the delay and emission of buses, but also keep the change of the vehicle delay and emission of all intersection area in a small range.