Evolving schedule graphs for the vehicle routing problem with time windows

The vehicle routing problem with time windows (VRPTW) is a very important problem in the transportation industry since it occurs frequently in everyday practice, e.g. in scheduling bank deliveries. Many heuristic algorithms have been proposed for this NP-hard problem. This paper reports the successful application of GrEVeRT (Graph-based Evolutionary algorithm for the Vehicle Routing Problem with Time windows), an evolutionary algorithm based on a directed acyclic graph model. On well-known benchmark instances of the VRPTW, we obtain better results than those reported by other researchers using genetic algorithms.