Truck scheduling in tank terminals

Tank terminals play a significant role in the storage and international transportation of goods such as liquids and gases. This paper focuses on a real-world problem where trucks must be assigned to loading stations which connect to tanks containing the product to (un)load. The typically limited operational space results in a specific type of blocking where trucks may be blocked not only at their assigned loading station, but also on their way towards it. The difficulty of fully understanding the repercussions of scheduling trucks to certain loading positions makes it extremely challenging for human operators to schedule trucks efficiently. The problem is contrasted against a range of active problems from the scheduling literature in order to establish its unique scientific merit. We provide a mixed integer programming formulation for this problem and a heuristic approach. The heuristic outperforms an estimation of the dispatching rules currently enforced by terminals, thereby providing such terminals with a practical tool for optimizing their operations. Moreover, in order to stimulate further research, a set of instances derived from real-world data has been made publicly available.