Solving a General Routing and Scheduling Problem by Chain Decomposition and Tabu Search

We modify the classical chain decomposition model for vehicle routing in order to formulate a very general class of vehicle routing and scheduling problems with time windows, in which vehicles may pick up loads while on the way to deliver others. We use the model as a framework for a tabu search heuristic that exploits the constraint structure these problems have in common while accommodating complex side constraints and objective functions. We test the heuristic computationally on several random problems and a problem supplied by the U.S. Military Airlift Command.