| In this dissertation, we explore modeling and solution methods for intermodal drayage operations. This research is motivated by the need to provide operational choices in drayage operations to increase efficiency; however, as shown in our work, the introduction of this flexibility in modeling and solution methods is challenging.; Intermodal freight transportation often includes modes such as rail, truck, and maritime between shippers and consignees. Drayage refers to the regional movement of loaded and empty equipment (trailers and containers) by tractors, and it is the most costly part of intermodal operations. Drayage movements are typically less than 50 miles, but consist of fairly complex operations, involving multiple intermodal and equipment yards, as well as multiple shippers and consignees. The objective of the drayage coordination problem as defined in this research is to schedule tractor and trailer movements at minimum cost by reducing the number of tractor trips needed and the number of empty miles traveled, which are also referred to as "non-revenue-generating trips".; This dissertation considers the Multi-Resource Routing Problem (MRRP) with flexible tasks as a method to model the routing and scheduling problems arising in drayage operations. Tasks may be either well-defined, in which both the origin and the destination of a movement are given, or flexible, in which the origin or the destination is chosen by the model. Several issues arise when solving an MRRP with flexible tasks. This dissertation focuses on: (1) the generation of feasible executions for flexible tasks; (2) the generation of feasible tractor routes; (3) the selection of near-optimal routes; and (4) the inclusion of future task requests.; In this dissertation, we propose and evaluate new methods to address these four issues. |
