Implications of cost equity consideration in hazmat network design

The hazardous materials (hazmat) network design problem (HNDP) is used to reduce the risk of transporting hazmat in the network by enforcing regulation policies. The goal of reducing risk can increase costs for hazmat carriers. Because the HNDP involves multiple parties, the cost increase for all carriers must be considered for implementation of regulations. Although upper bounds can be placed on the total increase, the actual cost increase for various origin-destination pairs can differ, resulting in unfairness among carriers. Thus, also considering cost equity in the HNDP is proposed. Additionally, because there are multiple solutions in current HNDP models and because of the possibility of unnecessarily closing road segments, a new objective considering the length of all the closed links is introduced. Computational experience is based on a real network, and results are shown for various cost consideration cases.