A diversion routing optimization model for urban evacuation planning

Due to the increasing number of disasters in recent years, the studies of evacuation planning and management continue to attract attention from both academia and practitioners. Even carefully laid-out evacuation plans can have a diminished capacity or become ineffective because of a crash, physical damage and other incidents blocking the vital evacuation route. As queue builds up along the corridor, both travel time and delay significantly increase from the incident location, which leads to extra evacuation time or even a failed evacuation. Diversion routing during evacuation is a computational challenging task because the number of evacuees often far exceeds the capacity, and the transportation networks involved in the calculation process are very large. A new diversion routing model was developed upon the minimum cost network flow model. It considers characters of diversion traffic in evacuation, while the prominent feature of the new model is to introduce the intersection control cost for diversion operation into the route optimization process. The model is more appropriate for identifying practical diversion routes in evacuation than the conventional ones.