The Vehicle Routing Problem with Multiple Trips

Non-asset based third-party logistics providers manage fleets of leased vehicles for their customers. Due to high leasing costs, minimizing the number of vehicles employed in daily operations is of primary concern to such firms. Consequently, routings that involve fewer vehicles and potentially longer travel times are favored over routings that involve additional vehicles. Constructing routes that meet such criteria gives rise to the vehicle routing problem with multiple trips (VRPM). Unlike the classical vehicle routing problem, the VRPM permits vehicles to make multiple trips to and from a central depot within a given time duration. We present a heuristic solution methodology for the VRPM. In contrast to previous research on the VRPM, our approach explicitly combines vehicle routes within the route duration limit. We present preliminary results of our algorithm on benchmark data sets and outline plans to improve upon these solutions.