Empirical analysis on hazardous material transportation using road traffic census and accident data

This study aims to identify the characteristics of hazardous-load transportation in Hokkaido, based on which a scheme for new road networks to reduce the risks associated with hazardous-load vehicles will be developed for the future. The study presents some new proposals, after analysing the current situation regarding hazardous-load transportation, examining its problems and estimating accident occurrence risk rates, with a focus on two strategies to reduce the risk of accidents involving hazardous-load vehicles, choosing less populated areas as optimum routes for the transportation of hazardous materials, and completing transportation operations in a short time by choosing the shortest route. Procedures taken are as follows. First, a general formula is proposed to model the risk incurred during transportation of hazardous materials. The effects induced by hazardous materials depend upon the distance, and the number of exposure victims is given as an expected value. ne risk evaluation model for transporting hazardous-loads can be expressed as the product of the expected number of exposure victims and the total travel distance. Second, the risk evaluation model is applied to the road network in the Nanyo area of Shikoku. As a method to minimise risk, two possible optimum routes, the shortest-distance route and the least-populated route, are proposed and analysed with the risk evaluation model. Optimum minimum-risk routes for hazardous-load transportation in the Nanyo network differ from OD pair to OD pair if the total travel distance is less than 60km. When the total travel distance is between 60km and 120km, the selection of the least-populated route produces a lower risk. On the other hand, the level of risk posed by the shortest-distance route becomes lower (than that of the least-populated route) when the total travel distance becomes 120km or longer. Therefore, the optimum route to minimise risk depends upon the nature of the OD pairs.