A variable neighborhood search algorithm with constraint relaxation for the two-echelon vehicle routing problem with simultaneous delivery and pickup demands

This paper considers a special vehicle routing problem, the two-echelon problem with simultaneous delivery and pickup demands (2E-VRPSDP). The 2EVRPSDP differs from classic transportation problems in two ways. First, freight depot to customers is managed by shipping through intermediate satellites. Second, each customer 2E-VRPSDP may have demands. an extension of (2E-VRP) (VRPSDP). A variable neighborhood search algorithm designed solve which both feasible infeasible solutions can be explored. Numerical results show that proposed effective provide reasonable within acceptable computational time.