The effects of trailer scheduling on the layout of freight terminals

Supervisors in a less-than-truckload freight terminal establish material flows inside the terminal by assigning incoming trailers to open doors. A common scheduling strategy is to look ahead into the queue of incoming trailers and assign them to doors to minimize worker travel. We develop a model of the resulting material flows and use it to construct layouts that exploit this type of scheduling policy. Based on data from a test site, our results suggest that look-ahead scheduling alone can reduce labor costs due to travel by 15–20% compared to a first-come–first-served policy. Layouts constructed with the material flow model provide further savings of 3–30% in labor cost due to travel, depending on the mix of freight on incoming trailers and the length of the queue of trailers from which the supervisor makes assignments.