A GRASP-ALNS combination for robust pickup and delivery problem

One of the well-studied routing issues is the Pickup and Delivery Problem (PDP). It aims to route a fleet of vehicles based on a depot to satisfy a set of transport requests subject to numerous constraints. In real-life cases, the satisfaction of those requests over a given time slot (1 day for example) may become impossible while respecting all problem constraints. Therefore, the studied variant is characterised by the selective aspect which consists of choosing a subset of demands to be honoured. In addition, travel times between sites may be uncertain and may vary according to several scenarios. The robustness consists then at finding a solution which remains feasible over all scenarios. Therefore, the goal of this study is to introduce lexicographic and metaheuristic approaches to solve the Robust Selective PDP (RSPDP). Numerous tests have been done on new instances for the considered variant, in order to show the efficiency of proposed approaches.