A Method for Calculating the Shortest Time Path for the Evacuation and Transfer of People at Risk of Flooding

Abstract

Reasonable planning of emergency evacuation paths is a significant measure to reduce potential casualties caused by floods. However, due to the complexity of evacuation environments, large-scale personnel evacuation may lead to increased road traffic load and congestion, which dynamically change the overall evacuation time under varying traffic conditions and thus affects evacuation efficiency. Therefore, by comprehensively considering the dynamic impacts of various factors on evacuation time-such as road length, class, width, bending condition, traffic load condition, crowd disturbance, an emergency evacuation path planning model with the goal of shortest evacuation time was constructed by coupling the Dijkstra Algorithm with an Impedance Function. This model was applied to the emergency evacuation path planning of Changkai dike breach in Fuzhou City, Jiangxi Province, China. The results showed that: (1) The evacuation path planning scheme improved the overall evacuation efficiency and significantly reduced the evacuation time; (2) As the evacuation distance increases, the dynamics impact of the various factors on evacuation time cost becomes increasingly significant. In this case, the time cost of the shortest distance path will be much greater than the time cost of the shortest time path.