A path-based approach for hazmat transport network design

The people living and working around the roads used for hazardous material (hazmat) shipments face the risk of suffering undesirable consequences of an accident. The main responsibility to mitigate the hazmat transport risk at a population zone belongs to the government agency with jurisdiction over that region. One of the common policy tools is to close certain road links to vehicles carrying hazmats. In effect, the road network available to dangerous goods carriers can be determined by the regulator. The transport risk in the region, however, is determined by the carriers' routing decisions over the available road network. Thus, the regulator needs to make the road closure decisions so that the total risk resulting from the carriers' route choices is minimized. We provide a path-based formulation for this network design problem. Alternative solutions can be generated by varying the routing options included in the model for each shipment. Each solution corresponds to a certain compromise between the two parties in terms of transport risk and economic viability. The proposed framework can be used for identifying mutually agreeable hazmat transport policies. We present two applications of the methodology to illustrate the insights that can be gained through its use: The first application focuses on hazmat shipments through the highway network of Western Ontario, Canada, whereas the second application studies the problem in a much larger geographical region that covers the provinces of Ontario and Quebec.