Developing a risk/cost framework for routing truck movements of hazardous materials

As the United States continues to increase its dependence on industrial technologies which require hazardous materials and generate hazardous wastes, concern is mounting over the safe transport of hazardous cargo. It is estimated that 1.5 billion tons of hazardous cargo are moved through the nation's transportation systems (excluding pipeline), with truck as the primary mode of transport. Because of the dynamic nature of exposure to the population and environment associated with the transport of hazardous cargo, it is important to develop an accurate representation of this type of transport risk, and to structure a framework for designating a permanent set of shipping routes based on optimizing across risks and costs. This paper describes a methodology which has been developed that incorporates risk and cost into a framework for optimizing the routing of truck movements of hazardous materials. Considerable attention is focused on the risk estimation part of this process, as this is a subject of much uncertainty and of considerable significance to policymakers. The resulting methodology is applied in a regional setting to illustrate its use as an analysis tool. Enhancements to the model structure and extensions beyond the truck routing problem are also discussed.