Creating schedules and computing operating costs for LTL load plans

This paper presents a computational approach for creating an operational schedule for the tactical load plan used by a less-than-truckload (LTL) motor carrier. A load plan determines how freight is routed through an LTL carrier's linehaul terminal network by specifying a sequence of transfer terminals for all freight shipments, but does not provide a timed schedule of trailer, tractor, and driver dispatches required to operate the plan. Developing a detailed operational schedule allows one to more accurately estimate the likely cost of a given load plan, along with other important performance metrics. Given a load plan, the scheduling approach we develop creates loaded truck dispatches between terminals with specified time windows, and then creates cyclic driver schedules to cover all dispatches. A computational study using data from a large U.S. LTL carrier demonstrates that our technology produces schedules that accurately model operational costs, typically within 2% of actual reported costs.