Heuristic Strategies for a Multi-Allocation Problem in LTL Logistics

We consider a multi-allocation problem where the transport is handled by complete (integer-valued) trucks. It consists of two parts: A number of hubs are chosen out of a given set of depots; then the given transport relations are individually assigned to two hubs, one hub or direct transport. Having four-index variables for the routing and integer variables for the trucks, this MIP becomes difficult. Our heuristic approach gives much better results than a Cplex implementation and can be used to generate a restricted problem which can again be given to Cplex. The idea is as follows: Considering the whole network as collection of n trees sending goods to a chosen depot, we improve the total costs step by step: For that we always take the edge with most expensive transport and try to find a new route for it. In our paper we will explain the theoretic ideas, point out different possibilities and connect them to computational results.