A tabu search heuristic for the vehicle routing problem with time windows and split deliveries

In this paper, we consider the Vehicle Routing Problem with Time Windows and Split Deliveries (VRPTWSD) and present a solution method based on Tabu Search and four different neighborhood structures. This problem is an extension of the Vehicle Routing Problem, where the start of service at each customer must be within a time window, and a customer may be serviced by more than one vehicle. The heuristic gives promising results when applied to realistic instances of the problem. It is also adapted to the problem where splitting is not an option, and experimental results have shown that the heuristic has improved 5 of the 56 best published solutions to the Solomon benchmarks, while matching or improving the best solutions in 10 problems.