Military vehicle shifting in Roll-on/Roll-off terminals

Roll-on/Roll-off (RoRo) vessels allow the overseas transportation of vehicles that can be driven onto a ship on their own or by means of a platform vehicle. In civilian RoRo operations, vehicles are typically loaded in relatively large batches according to their destination terminals. In this article, however, we focus on a military setting, where the loading of vehicles strictly follows vehicle characteristics and involves multiple decision makers that influence the overall process. The vehicles arrive at the terminal in given sequences and need to be shifted to a parking area such that they can later be loaded onto the ship according to a given stowage plan that is related to the vehicle characteristics. We formulate the underlying operational planning problem of shifting military vehicles in a RoRo terminal and provide theoretical insights regarding its computational complexity, associated meta problems and the structure of feasible solutions. We then leverage these insights in a mathematical model and heuristic approaches that are designed to be easily implementable in practice. We evaluate the heuristics in a comprehensive computational study and derive implications and recommendations for their application in practice.