A Study of Transit Evacuation Route Planning Based on Time-Expanded Network

Abstract

This research focuses on identifying optimal evacuation routing plans in public transit networks during various extreme events in urban road networks. The public transit evacuation system is modeled by a time-expanded network, based on a dynamic network flow model, and aims to minimize the total evacuation clearance time. This model transforms the public transit evacuation scheduling problem into a mixed-integer linear program (MILP). Also, a heuristic TABU-based search algorithm is used to find a high-quality solution in a reasonable amount of time. Finally, a case study is conducted using the central road network of Changchun city in China. Many numerical experiments are implemented in CPLEX 9.0 and the results show that time-expanded networks can effectively represent transit evacuation dynamics and the heuristic TABU-based algorithm can make an appropriate trade-off between solving efficiency and accuracy. INTRODUCTION In general, emergency evacuation of urban areas has gained prominent attention from both practitioners and researchers in the last three decades in the world (Wolshon et al. 2005, An et al. 2008, Liu et al. 2006). Among available modes of transportation, the use of public transit in evacuation situations is not well studied or understood (Liu and Hu. 2008). The use of public transit during evacuation is more crucial and should be well studied in some developing countries such as in China, as the population of transit-dependent citizens is very large. In addition to people without vehicles, the indigent, the elderly, the infirm and tourists also rely on the public transit system for evacuation. Accordingly, the purpose of this study is to make the existing transit system viable in emergency situations by developing a ICCTP 2009: Critical Issues in Transportation Systems Planning, Development, and Management ©2009 ASCE 1543