A general variable neighborhood search for the swap-body vehicle routing problem

The Swap-Body Vehicle Routing Problem, a generalization of the well known Vehicle Routing Problem, can be stated as follows: the vehicle fleet consisting of trucks, semi-trailers, and swap bodies, is available at a single depot to serve a given set of customers. To serve a subset of customers, one may use either a truck carrying one swap body or a train (a truck with a semi-trailer attached to it) carrying two swap bodies. In both cases, a vehicle (a truck or a train) must perform a route starting and ending at the depot, so to satisfy demands of visited customers, maximal allowed route duration, allowed load on the used vehicle, and accessibility constraint of each customer. The accessibility constraint indicates whether a customer is allowed to be visited by a train or not. In addition, a set of swap locations is given where semi-trailers and swap bodies may be parked or swapped. The goal of the Swap-Body Vehicle Routing Problem is to minimize the total costs consisting of the fixed costs for using vehicles and costs for performing routes. In this paper, we propose two general variable neighborhood search heuristics to solve this problem. The quality of the proposed methods is evaluated on the instances provided by the organizers of VeRolog Solver Challenge 2014.