A three-stage heuristic for the capacitated vehicle routing problem with time windows

Abstract

In this paper we propose to solve the Capacitated Vehicle Routing Problem with Time Windows (CVRPTW) by using a three-stage solution procedure. CVRPTW is defined by a set of customers (with associated demands and time windows) and a set of vehicles (with a given capacity) and the aim of the problem is to serve all the customers inside their respective time windows. There are two objectives to optimize, the first one consists in using the minimum number of vehicles and the second one is to minimize the total distance traveled by all the vehicles. The proposed heuristic combines (i) a clustering stage in which the set of customers is divided into disjoint clusters, (ii) a building stage that serves to provide a feasible tour in each cluster and, (iii) a local-search stage that is applied in order to try to improve the quality of the solutions obtained from the second stage. The computational investigation, conducted on a class of benchmark instances of the literature, shows that the results reached by the proposed heuristic remain competitive when compared to the best known solutions taken from the literature.