Modeling Single Intersection Real-Time Control Based On Petri Net

With the rapid development of the economy and urban transport needs, the popularity of vehicles, traffic problems are badly serious. Accurate forecasting and efficient traffic flow of traffic control can not only reduce the transportation cost of implementation. but can also reduce pollution and traffic and bring economic losses. Accurate and effective model for traffic flow is the foundation of traffic control and traffic flow forecast. The traditional model of traffic flow has been unable to meet increasingly complex large transport system or to perform mixed and complex characteristics of the transport system. Therefore, the Petri model has more advantages than other type models to be applied to the transport system.According to the characteristics of the traffic flow in a single intersection of a city, a model was established with Petri net for the multiphase real-time control of the traffic signal in the intersection. A simulation was carried out on this basis and the validity was checked. Traffic system in the city way is a complex real-time system, possessing the character synchronization, concurrence, conflict, mutex, resource sharing of discrete event system. It is a completely new method for performance analysis and real-time control in modeling the single intersection with Petri net according to the set logical rule, phase and phase sequence, circle length and optimizing the control through adjusting the parameters according to the actual intersection condition.The main part of the article gives the signal timing Program, including the choice phase (Phase IV), and according to the phase, the arrival o traffic flow and delay laws of this crossroad, gives the objective signal timing function.Additionaly the Petri net modeling has obvious advantages: the concrete and abstract in levels.