Efficient handling of synchronization in three vehicle routing problems

This paper presents a synthesis of contributions to the solving of three vehicle routing problems involving synchronization constraints. These problems are: the Pickup and Delivery Problem with Transfers (PDPT), studied during the PhD of Renaud Masson, co-advised with Olivier Peton [4], the Two-Echelon Multiple-Trip Vehicle Routing Problem with Satellite Synchronization (2E-MTVRPSS), studied by Philippe Grangier during his PhD, co-advised with Michel Gendreau and Louis- Martin Rousseau [2], and the Heterogeneous Full Truckload Pickup and Delivery Problem with Time Windows and Resource Synchronization(HFTPDPTW-RS), under study by Axel Grimault in his PhD and co-advised with Nathalie Bostel [3]. All these problems have been solved with an Adaptive Large Neighborhood Search (ALNS). A special focus is given to the temporal feasibility evaluation of an insertion which has been proposed for the PDPT [5] and extended to the other problems. The concept of forward time slack [6] is extended to provide a constant time feasibility test of temporal constraints. Experiments confirm the solving time reduction provided by the implementation of this test in a meta-heuristic.