Influence of Residential Geographic Features and Evacuation Routes on Evacuation Time and Success Probability: A Case Study of the 2015 Kanto–Tohoku Heavy Rain in Joso City

抄録

Floods pose a significant threat to urban populations particularly those in low-lying areas, where evacuation routes can quickly become impassable. This case study focused on the 2015 Kanto–Tohoku heavy rain in Joso City to investigate the effect of residential geographic characteristics and evacuation routes on evacuation time and success during flood events. By integrating flood simulation data with a multiagent evacuation simulation model, this study evaluated evacuation feasibility across seven residential clusters, which have distinct topographical and hydrological features. It identified three key geographic factors as critical to evacuation outcomes: residential elevation, inundation from tributary flooding, and surrounding low-lying terrain. Clusters at higher elevations achieved high evacuation success rates despite delayed departure, while low-lying clusters exhibited high failure rates regardless of the route taken. Furthermore, clusters at higher elevations and farther from shelters highlighted the effectiveness of adaptive route selection strategies (evacuating inundated areas via the shortest possible route), which helped increase evacuation success rates and reduce evacuation times.