The Study Of The Capacity Of Sigalized Intersection Based On Petri Nets Modeling And Simulation

Urban road network is the backbone of the entire urban transport network, which bears the major transport tasks. As an important part of urban road, signalized intersection plays an important role in the road of convergence, the size of its capacity largely determines or restricts the size of the entire city road network capacity which becomes the emhasis of road network planning, construction, reconstruction and traffic management, as well as the main bottleneck affecting urban road network capacity.City signalized intersection is a typical hybrid system, including continuous traffic flow and discrete signals. Petri nets can directly reflect concurrent distributed architecture of hybrid systems, so it can be used to analyze not only the static structure, but also the dynamic behavior. Therefore, Hybrid Petri nets is used to model signalized intersections.The analytical model of the intersections and road streches are detailedly descripted, the hybrid Petri net models of the two-phase and four-phase intersection are established, and the confilictions are solved. What’s more, the hybrid Petri net models are validated by silulation with MATLAB.The hybrid Petri net model proposed in the article is simulated with MATLAB software with data collected from a four-phase traffic signal intersection of Chengdu. Output flowrate and traffic denisity under different OD matrixes are obtained. And the simulation results are analyzed to verify the reliability of the model. The design capacity of signalized intersection is improved by optimizing the signal timing, and the maximum hourly traffic volume is increased through Petri nets simulasiton to obtain greater utilization of the capacity.By using hybrid Petri nets for modeling urban transportation systems, the hybrid characteristics of urban traffic systems are fully demonstrated. The results of this study could be uesd to provide a certain amount of technical support and theoretical basis for the city’s transportation system analysis and control.