A network flow based optimization approach for hurricane evacuation planning

Abstract

We address the problem of finding the evacuation route, flow, and schedule in a short-notice evacuation problem due to natural disasters such as hurricanes. We formulate this problem as a network flow optimization model. Our goal is to find shortest paths in time and their flows to maximize the total number of evacuees from the danger areas to safe destinations. Since the corresponding optimization model is too large to solve on a PC, a heuristic algorithm has been developed to facilitate the solution process. This algorithm provides an efficient evacuation plan that includes optimum evacuation route, flow, and also schedule for every node in the evacuation area. An important characteristic of our model is that the flow rate of a path is assumed to be constant although each path is allowed to have a different flow rate. This is different than other approaches proposed in the literature. In fact, it is much easier for emergency management staff to implement a fixed rate flow plan than a variable evacuation flow rate in practice. We present some numerical experiments to show the strengths of our approach.