A Simultaneous Route and Departure Time Choice Model for Evacuation Planning

Evacuation is critical in emergency management. Efficient tools are needed to produce evacuation plans that identify routes and schedules of evacuation vehicles to minimize the time to evacuate population from affected area to safety in the event of disasters. Both static network flow models and dynamic network flow models have been widely used in evacuation planning, but little attention has been given to the fact that travel speed is not only time-dependant but also flow or density-dependant. A discrete simultaneous route and departure time choice model is presented; the objective is to minimize the total evacuation time by optimizing the number of vehicles assigned to route and departure time choices, given the evacuation demand of each origin. Flow propagation is described by a link travel time function. A heuristic algorithm is proposed to approximate the optimal solution by simulating the route/time swapping process. A numerical example is given.