Post-earthquake modelling of transportation networks using an agent-based model

Surface transportation systems are an essential part of urban transportation infrastructure and are susceptible to damage from earthquakes. This damage, along with the lack of prior warning of earthquake events, may lead to severe and unexpected disruption of normal traffic patterns, which may seriously impair post-disaster response. Accordingly, it is important to understand the performance of urban transportation systems immediately following an earthquake, to evaluate their capability to support emergency response, e.g., the movement of firefighters, search and rescue teams and medical personnel, and the transportation of injured people to emergency treatment facilities. For this purpose, a scenario-based methodology is developed to model the performance of a transportation network immediately following an earthquake using an agent-based model. The model accounts for the abrupt changes in destination, irrational behavior of drivers in the chaotic aftermath of a severe earthquake, unavailability of traffic information and impairment in traffic capacity due to bridge damage and building debris. An illustration using the road network of Tangshan City, China shows that the method can capture the traffic flow characteristics immediately after an earthquake and can determine the capability of the transportation network to transfer injured people to hospitals. Thus, it can provide rational support for evaluating the performance of the surface transportation system under immediate post-disaster emergency conditions.