A parallel tabu search heuristic for the vehicle routing problem with time windows

The vehicle routing problem with time windows models many realistic applications in the context of distribution systems. In this paper, a parallel tabu search heuristic for solving this problem is developed and implemented on a network of workstations. Empirically, it is shown that parallelization of the original sequential algorithm does not reduce solution quality, for the same amount of computations, while providing substantial speed-ups in practice. Such speed-ups could be exploited to quickly produce high quality solutions when the time available for computing a solution is reduced, or to increase service quality by allowing the acceptance of new requests much later, as in transportation on demand systems. (C) 1997 Elsevier Science Ltd.