Planning the Incorporation of Logistics Service Providers to fulfill Precedence- and Time Window-Constrained Transport Requests in a Most Profitable Way

We investigate an extension of the Pickup and Delivery Problem with Time Windows (PDPTW) in which only a part of the available request portfolio can be fulfilled by own equipment and the remaining requests are served by subcontracted carriers (Logistic Service Providers). The costs for the fulfillment of the request portfolio result in the sum of travel costs for the self-served requests and the charges paid to the Logistic Service Providers. A Memetic Algorithm (MA) is configured to determine solutions of this combined selection, assignment and sequencing problem. Special genetic operators are proposed to identify those requests that should be served by Logistics Service Providers in order to minimize the overall fulfillment costs. By means of suitable benchmark instances, the capability of the algorithmic approach is assessed and the impacts of the selection feature are analyzed.