Synchronizing Trucks and Trailers in a Multiresource Problem with Variable Neighborhood Search

A real-world container drayage problem in which containers are transported between an intermodal terminal, a container terminal, and customer locations is considered. The problem was modeled as a multiresource routing problem (MRRP) that included trucks, trailers, and containers. Given a fleet of trucks and trailers, the goal is to use these resources most efficiently to complete a number of given orders. Orders consisted of several tasks with time windows, such as picking up a container at the terminal, delivering it to a customer, and bringing the processed container back. A challenging aspect of this problem is the management of trailers, which are required to transport the containers. Here, the compatibility between container types and trailer types must be considered. Thus, the decision of which trailer should be attached to which truck depends on the containers that must be transported, the day of availability of trailers, and the toll costs of the truck and trailer combination on the highways. This paper presents an efficient way to model this problem and proposes a metaheuristic approach based on a variable neighborhood search. It uses a compact solution representation and tailored neighborhood structures to reduce the search space. Classical MRRP neighborhood structures, as well as problem-specific ones, were used in combination and contributed to the overall success. The results show that the given real-world problem can be solved efficiently, and it can be shown that with proper planning, the utilization of resources can be increased.