An Analysis to Manage the Current Conditions of Evacuation Routes in a Historic Preservation Area: The Probability of Street Blockades

Abstract

Historic preservation areas are particularly vulnerable to disaster because many people inhabit these areas. These areas contain wooden houses built close to one another. It can be difficult to manage widening narrow streets in these areas to prevent disasters. Therefore, it is crucial to develop two-way evacuation routes in historic preservation areas. This study attempts to develop two-way evacuation routes for a historic preservation area based on the probability of street blockade use. We chose to study Hamanaka Machi Hachihongi Syuku, which is located in Kashima City, Saga Prefecture, Japan. It was designated an important preservation district that includes traditional buildings under the Act for the Protection of Cultural Properties. First, we defined the probability of street blockade use in historic preservation areas by examining a street blockade for a normal city area created by the Tokyo Fire Agency. We examined streets less than 4 m in width, the structure of houses that lined those streets, and the distances from houses to main streets that were more than 4 m in width. Second, we calculated evacuation times from each house to final evacuation sites with the use of blockades and in cases with over 70% probability of street blockade use based on a multi-agent system. We also considered the rooms in which vulnerable people sleep. The results revealed: (1) In cases that did not use blockades, evacuations, including evacuations of vulnerable people, were completed in ten minutes (2) In cases with over 70% probability of street blockade use, some evacuations were not completed because they required the use of roundabout routes to avoid blockades. We discovered some fundamental problems involved in the management of evacuation plans developed to prevent large disasters that relate to the determination of appropriate streets to be blocked in the study area.