Abstract: This paper proposes a traffic emergency control strategy model based on Petri nets to solve the problem how the emergency vehicles reach the destination faster in urban traffic network. First, based on the correspondence between travel time and traffic flow in the Davidson function, it will get shortest travel time on the road of the emergency vehicles, and then, this time is regarded as the weight to calculate the shortest path using the Dijkstrsa arithmetic. In the next place, the traffic lights in the shortest path are adjusted by the emergency lights control strategy to reduce the lag time in the intersection, in addition, the emergency traffic lights signal control model of emergency vehicles in the intersection is built using the Petri net theory. To describe the emergency signal control strategy dynamic behaviors, the key elements of its parts are designed for the corresponding Petri net models. Finally, an experimental comparison between emergency control strategy and common strategy is made through a simulation model. Experimental results show that the former can optimize the arrival time of emergency vehicles.

Key words: traffic emergency control strategy, Dijkstrsa algorithm, Petri net, path optimization

摘要： 针对城市交通网络中紧急车辆在行驶区段中如何较快地到达终点的问题，提出了一种基于Petri网的交通紧急控制策略模型。利用Davidson函数中行驶时间与交通流之间的对应关系，得出紧急车辆在道路上的最短行驶时间，并将其作为权重，运用Dijkstrsa算法进行最短路径寻优；采用紧急信号灯控制策略对最短路径上的交叉口信号灯进行了调整，减少紧急车辆在交叉口的延滞时间，并运用Petri网理论，建立紧急车辆在交叉口的紧急信号灯控制模型。为了描述紧急信号灯控制策略的动态行为特性，将其各部分关键要素分别设计为相应的Petri网子模型。通过模型的一个仿真实例，进行了紧急控制策略与普通策略的实验对比，实验结果表明前者可以对紧急车辆的到达时间进行优化。

关键词: 交通紧急车辆控制策略, Dijkstrsa算法, Petri网, 路径寻优