Study on evacuation routes under unexpected event based on Petri net

If we consider the delay of evacuation routes under unexpected events, the delay caused by traffic light at intersections cannot be ignored. Since an intersection with traffic light consists of a repeated sequence of time windows, different starting time of evacuation corresponds to different intersection delay and different evacuation routes. Considering the intersection delay and capacity, the definition of extended flow Petri net (EFPN) is given, and a minimum cost flow algorithm based on EFPN is given to optimize the superior evacuation routes and the flow assigned to each route from the accident place to the designated destination. Finally, the effectiveness of this method is shown by a numerical example. The results indicate that this method can better satisfy the demand of evacuation time and can give consideration to route optimization at the same time.