Mixed global and local assignment algorithms for quasi-dynamic local truckload trucking operations with strict time windows

Examined are the trade-offs associated with local and global, but myopic, assignment heuristics for local truckload trucking operations such as those associated with drayage operations near intermodal facilities. These operations involve a combination of loads that are known at the beginning of the day and those that arrive dynamically throughout the day. Some of the dynamically arriving loads are revenue-generating moves, and others are trailer, chassis, or container repositioning moves. Because a significant fraction of the day's loads are known a priori, dispatchers would like to be able to construct schedules for the day and then to make minor changes to these schedules as the day progresses. The efficiency of an operation in which new loads are added to or appended to schedules constructed at the start of the day versus one in which the whole system is reoptimized several times during the day is examined. The reoptimization method does not seek to preserve current schedules, but the local optimization techniques do. Solutions were examined with a geographic information system-based simulation model developed for this purpose.