The Effects of Network Size and Variables on Solution Approach in Hazmat Routing Problems

Routing problem is a serious concern of road safety in Hazmat transportation due to their accident impacts. A number of mathematical models have been developed to determine the route of hazmat transportation to minimize the risk and impacts and solution approach have been considered regarding to their characteristics such as network size and type of variables. In this paper, mathematical models and type of variables in hazmat routing problem have been studied and different approaches of solving the problem have been analyzed. Results show that both size of network and type of variables have significant effects on solution approach. When the size of network is getting large, the solving approach tends to heuristic methods because of running time and when the variables are getting to uncertainty, exact solution approaches are rarely used because of the difficulties in modeling procedure. Results also show that the type of objective functions including bi-level, two-stage, and utility, considered regarding to decision makers, causes significant effects on solution approach.