Mathematical Models and Algorithms for Logistics Operations: The Case of Hazardous Materials

Hazardous Materials transportation risk mitigation may be achieved by reducing the accident probability and alleviating the associated potential consequences. The consideration of risk as a criterion for selecting Hazardous Materials distribution routes contributes substantially to the reduction of accident probability and the severity of the accident consequences. Furthermore the optimum deployment of the emergency response units for covering the hazardous materials routes contributes significantly to the reduction of the accident consequences. Vehicle routing and emergency response facility location are two of the most frequently faced logistical decisions in Hazardous Materials distribution management and emergency response planning respectively. In particular, Hazardous materials routing can be defined as a bi-objective vehicle routing problem with time windows since risk minimization accompanies the cost minimization in the objective function. Furthermore, the emergency response unit location problem aims at locating a set of response units in order to optimize the performance of the system. The heavy computational burden for solving the emerging mathematical models especially in cases of large-scale distribution networks, led to the development of two new heuristic algorithms. The algorithm for the Hazardous Materials routing problem has been applied to several benchmark problems providing results superior to other competing algorithms. Due to the lack of benchmark problems, the algorithm for the emergency response units location problem has been applied to several case studies providing near optimal solutions.