An improved sequential insertion initialization algorithm and Tabu search to vehicle routing problem with time windows

The vehicle routing problem (VRP) is a well-researched problem in the operations research literature. This paper studies a vehicle routing problem with time windows. Based on Solomon’s re-search, an improved sequential initialization algorithm, Solomon i1 with DTWC (Solomon i1 with Dynamic Time Windows Compatibility), is proposed in this paper to construct feasible initial solutions with higher quality in less calculation time. A tabu search with VNS (Variable Neighborhood Search) and the Metropolis criterion is used to further optimize the solutions that the proposed initialization algorithm provides. We run computational experiments on cases of well-known problems. Results show that compared to the initialization method before the change, our improved initialization approach performs well in terms of providing a better feasible initialization solution in less time, with an average 10 % improvement in solution quality and an average 34 % computational time savings. The proposed initialization algorithm’s superiority is also demonstrated by the tabu search’s better performance on the initial solutions it produces.