Comparison between Combined and Separate Approaches for Solving a Location-Routing Problem in Hazardous Materials Transportation

In the case of hazardous materials management, selected routes for carrying hazardous materials (i.e., hazmat) have significant effects on locating hazmat distribution centers. Since, risk and cost are usually considered as two main attributes to determine the best routes, optimized locations are sequentially outlined depending on selected routes. In the present paper, two different approaches of developing separate and combined models of routing and locating problems have been utilized to determine hazmat transport routes together with optimized locations for distribution centers. While mathematical models are developed to carry out the above concepts, a three-stage procedure has also been developed to determine the routes and hazmat quantities should be required to transport for each origin destination pairs. An experimental network consists of eighty-nine nodes and one hundred and one links has been used as case study for analytical process and model validation. Results revealed that, although two different models have been developed following the above approaches, but results are the same. Therefore, decision makers who are dealing with hazardous material management should not be worried about the approach which is better to be utilized for solving routing-locating problem.