Near optimal allocation strategy for making a staged evacuation plan with multiple exits

Recent natural or man-made disasters have reminded the government to prepare an efficient evacuation plan in advance to cope with extreme threats, especially for urban area with high density of population. In view of this, many approaches have been proposed from different viewpoints, but limitations of them always exist more or less. Instead of presenting a new approach, we expand an existing staged evacuation algorithm for one exit to solve evacuation problems with multiple exits in this paper. The principle is to assign evacuees to different exits to translate a multi-exit problem to several single-exit problems. The objective is to balance traffic flow among exits and reduce the total clearance time, and thus a series of allocation and optimisation strategies are proposed to approach it. Experiments validate the proposed methods, and a simulation program is also developed to visually examine their performance.