Minimax Population Exposure in Routing Highway Shipments of Hazardous Materials

A routing model for hazardous materials with two objectives—to minimize maximum population exposure and to minimize total travel time—is introduced. The population exposure is quantified by the number of people in an impact circle of a selected radius. To solve this two-objective problem, the focus is placed on the second objective, with a constraint on the first objective. This results in a problem that is easy to solve and has a solution that is easy to interpret. To demonstrate the use of this model, a case of nuclear waste shipments (i.e., spent fuel) in the United States in considered. The model is applied, with two bounds on high-level population exposure, to 10 nuclear waste origins. The results of this application are reported. The model behaves in a predictable (and desirable) way, avoiding major population centers via detours. With its ability to quantify trade-offs between competing objectives, and its capacity to generate multiple routes for a shipment, the model has the potential to serve in a decision-support role for planning hazardous materials routes.