Estimation of impacts of volcanic ash fall from Mt. Fuji eruption on freight transport and effects of partial restoration of highways

Volcanic eruptions produce significant ash fall. If Mt. Fuji erupts, the ash fall could directly affect road transport function in the Greater Tokyo area. An eruption has the potential to impact network traffic by altering the shortest route and impacting minimum transport costs between different regions. This study aims to calculate the impacts of volcanic ash fall on freight transport and commodity trade and the effects of partial restoration of trunk highways on the economy. We estimate the impacts by applying an integrated system of transport network and input–output model, the inter-regional commodity flow model. The model estimates regional and inter-regional commodity flows and transport network flows simultaneously by analyzing the interactions between network flows and commodity trade demand. The estimation results show a deterioration of accessibility in and around the area where ash fall deposits occur. The geographical characteristics of the influence on freight transport and trade demand are shown. Our results imply that the southern regions, such as the Izu peninsula and areas around Shizuoka city, will be severely affected. We also examine a simulation to estimate the effects of a restoration plan of trunk highways crossing the affected area, assuming that restoration efforts resources are limited. The simulation analysis suggests a significant mitigation of the impacts of ash fall with the restoration. The estimation results imply that prioritizing the restoration of trunk highways can represent not only a realistic policy solution but also an efficient recovery strategy.