A Decision Support System for a Multi-trip Vehicle Routing Problem with Trucks and Drivers Scheduling

Many real-world transportation problems can be modeled as variants of the well-known vehicle routing problem (VRP), where a fleet of vehicles based at a central depot is used to deliver freight to clients at a minimum cost. Frequently, the problems defined in the VRP literature and the corresponding solution algorithms do not catch all the problem features incurred by the companies in their every-day activity, and further flexibility is needed during the decision process to make adjustments on the fly. In this paper, we present a decision support system developed for an Italian pharmaceutical distribution company to deal with a Multi-Trip VRP characterized by additional constraints and Truck and Driver Scheduling. The problem is solved in the software with a two-phase algorithm: the first phase consists of an Iterated Local Search metaheuristic that defines the vehicle routes, whereas the second phase invokes a mathematical model to assign trucks and drivers to the routes. The software allows, between the two phases, changes in the solution to better fit the company requirements. Computational results prove the effectiveness of the proposed method.