Vehicle routing and scheduling in cross docks with forward and reverse logistics

Cross-docking is a useful logistic practice used by many companies to reduce logistical costs. Cross-docking facilities are responsible for transferring products from suppliers to retailers and vice versa. Furthermore, vehicle routing is an important issue with regard to cross-docks. This paper investigates, for the first time, a vehicle routing problem in a distribution network with a cross-docking center by considering both forward and reverse logistics in an integrated model. In this regard, two strategies are presented to tackle the forward and reverse logistics. A mathematical model is developed for each strategy in order to find the best solution to transfer products from suppliers to retailers and then return products from retailers to suppliers through cross docks with minimum transportation cost. As the resulting mathematical model is NP-hard, a simulated annealing based heuristic algorithm is developed to optimize the model. Finally, these strategies are compared in terms of cost and the results demonstrate that the second strategy is superior to the first one.