The role of vehicular considerations in tsunami shelter location optimization

Abstract

Using vehicles during tsunami evacuation might exacerbate road congestion, potentially increasing casualties. However, since the 2011 Tohoku Earthquake Tsunami, vehicular evacuation during tsunamis has partially been permitted, especially to assist elderly and disabled individuals with mobility challenges. The present study aimed to elucidate the impact of vehicular use on reducing mortality rate by introducing a new tsunami evacuation shelter in a given coastal area. To do so, the authors applied an agent-based tsunami evacuation simulation model that can account for behaviors of both pedestrians and vehicular evacuees to three Japanese coastal cities (Mihama Town, Shingu City, and Minabe Town) considering future Nankai–Tonankai Earthquake Tsunami scenarios. The authors first determined mortality rates under scenarios both with and without vehicular evacuation using current shelter placements. Subsequently, mortality rates with the introduction of a new tsunami evacuation shelter were examined for both scenarios. The findings showed that effective shelter locations for minimizing mortality rates varied depending on whether vehicular evacuation was considered. It was also found that the effectiveness of vehicular use during evacuation and the strategic placement of new tsunami evacuation shelters are highly dependent on local factors such as population distribution, existing shelter locations, and road layouts. These findings underscore the necessity for area-specific tsunami evacuation simulations to construct robust evacuation strategies.

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