The Capacitated Vehicle Routing Problem (CVRP), a fundamental combinatorial optimization problem in transportation logistics and distribution systems of considerable economic significance, was first introduced by Dantzig and Ramser (1959), then extensively studied in the literature in various versions and approached using alternative algorithms.
The problem consists, in its basic version, of designing a set of minimum cost-routes for a number of identical vehicles having a fixed capacity to serve a set of customers with known demands. Several structural constraints can be added to the basic CVRP giving rise to many variants such as time windows for the customer to be served, limits on the lengths of the routes and limits on the time that a driver can work.
Since the CVRP is a NP-hard problem, three solution approaches are typically employed: heuristics, approximation and exact methods (Alba and Dorronsoro, 2006 and Osman, 1993). Only instances of small size can be solved to optimality using exact solution methods. While heuristics do not provide guarantees about the solution quality, they are useful in practical contexts thanks to their speed and ability to handle giant instances. An approximation algorithm is a special class of heuristics that provide a solution and an error guarantee.
We show through the present study the powerfulness of linking GIS with optimization tools to solve routing problems. Our DSS integrates Google Maps and the TS metaheuristic for the loading-routing problem modeled as a CVRP. The proposed tool firstly inputs the basic parameters of the problem then, extracts spatial information from the geographical database (GDB). The numerical solution obtained by applying a TS is plotted on a map and commented by providing a detailed report on the proposed scenario. The parametrization of the solution approach is discussed in order to output the near-optimal solution that coincides with the decision maker’s preferences. To check the validity of the proposed DSS, we address a real case study in the city of Jendouba (Tunisia).
This paper is structured as follows. The CVRP is described and stated mathematically in Section 2. In Section 3, the main steps of the proposed DSS are outlined and described. The TS metaheuristic that generates the numerical solution of the DSS, enhanced by neighborhood techniques, is detailed in Section 4. Experimental results within the region of Jendouba (Tunisia) are reported in Section 5.