Wataru TAKAMURA

A Method for Determining Relief Supply Transport Routes Before and After a Disaster Considering Uncertainties

Kazushi SANO

In recent years, disasters in Japan have become more severe and more frequent, and the importance of advance disaster management planning and disaster response measures has increased in each municipality. The problem with disaster response is that, unlike pre-planning, the disaster situation and limited resources are constantly changing with the time elapsed since the disaster occurred. Therefore, this study examines a routing algorithm that calculates a solution that satisfies the transport conditions and constraints that change with the time elapsed since the disaster. First, the current disaster response system of the target area, Nagaoka City, was clarified and a system was constructed to support the decision-making process of the local government in transporting relief goods based on these issues. The constructed system was then operated on a trial basis during the city's comprehensive disaster drill to identify problems with the existing algorithms. Following this, an algorithm that takes into account the constraints of transporting supplies from multiple locations and the number of trucks available was considered. The results of the case study confirmed that a feasible solution could be calculated. Finally, as it is difficult to obtain an accurate disaster/damage situation immediately after a disaster, an algorithm that is as unaffected as possible by uncertain road conditions was considered. Robust optimization was used in the algorithm, where the delay time of a link was formulated as a parameter based on the inundation depth of the road network over the expected flood inundation zone. The results of the case studies show that the routing can take into account the risk of flooding for each flooding scale. The overall conclusion is that it is possible to calculate highly feasible solutions by using different algorithms for different conditions before the disaster, immediately after the disaster and after sufficient time has elapsed since the disaster.