A procedure for optimizing hazardous materials transportation including road infrastructures’ characteristics and door-to-door attempted deliveries

Abstract This study deals with downstream logistics of Liquefied Petroleum Gas (LPG) by tank trucks both at regional and urban level. The distribution problem is formulated as a capacitated Vehicle Routing Problem (VRP) with time windows. Its solution is based on a two steps procedure with the aim of maximizing the revenue of the logistic operator: 1) in the first step, the problem is solved at suburban level, where each delivery point represents a municipality in the study area. The employed objective function of the VRP has been conceived as to integrate the usual operating costs with aspects related to infrastructure characteristics of the used paths; 2) in the second step, door to door deliveries at urban level are attempted, taking into account the operating costs and the last delivery time for each potential client. The method has been applied in a real case study based in the city of Perugia, Italy. Sensitivity analysis considering different values for the parameters regulating the relative weights of the objective function components has been performed. Results show that the potential revenues for the operator can be doubled through the proposed optimization procedure. Moreover, explicitly taking into account that not all roads are suitable for vehicles transporting hazardous materials can increase the security of the distribution process, resulting in a service cost increase of just +1.4% with respect to extant conditions.