Abstract: When emergency vehicles are used for evacuation and rescue under unexpected events, the superior evacuation routes should be determined according to the time delay. The travel time of an emergency vehicle on a road section is depended on the traffic flow on this road, and emergency vehicle starting at different time will face different phases when arriving at an intersection, which in turn results in different intersection delays. A generalized timed Petri net model of urban traffic network is established. Considering the uncertainty of signal at intersections and the time dependence of road travel time, a labeling algorithm based on the parameters of Petri net is designed to find the optimal evacuation route for emergency vehicles. Finally, the effectiveness of the method is indicated by a numerical example. For the purpose of comparison, evacuation routes corresponding to different starting time- same marking and same starting time- different marking are listed, which indicates that this method can better reflect the influence of evacuation starting time and traffic flow on evacuation routes.

Key words:

Evacuation routes, generalized timed Petri net, unexpected events, time-dependence, label algorithm

摘要： 在发生突发事件利用应急车辆进行疏散和救援时，需根据时间延误确定车辆的最佳疏散路线。应急车辆在路段的走行时间依赖于路段上的车流量，且出发时刻不同，到达交叉口时对应着不同的相位，从而产生不同的交叉口延误。建立了城市交通网络的广义时延Petri网模型，考虑交叉口信号灯延误的不确定性以及路段走行时间的时间依赖性，以Petri网参数为基础设计了标号算法以寻求应急车辆的最佳疏散路线。最后通过数值算例说明了方法的有效性，并对不同疏散开始时刻同一标识以及同一疏散开始时刻不同标识时得到的疏散路线进行了对比。结果表明该方法可以很好的反应疏散时刻和路段流量对疏散路线的影响。

关键词: 疏散路线, 广义时延Petri网, 突发事件, 时间依赖, 标号算法