Modeling of evacuation and background traffic for optimal zone-based vehicle evacuation strategy

This paper discusses details of developing an optimal zone-based vehicle evacuation strategy based on an optimization-simulation approach. The optimal egress strategy is obtained by solving a universal quickest flow problem, and the solution is implemented and evaluated in a mesoscopic simulation model. Evacuees would follow optimal routes to safe locations outside the hot zone and then select behaviorally realistic routes to their final destinations. Background traffic is included in the model to simulate more realistic traffic conditions. The route choice of background traffic in response to the evacuation strategy and driver information strategies is carefully addressed. Operational issues such as temporal loading intensity and queuing at parking lots are also modeled and discussed. The modeling framework has been applied to a bomb threat scenario at a football stadium. The case study shows that the proposed methods generate reasonable and meaningful results for the intended no-notice scenario.