while some of them may not be allowed in reality, it is not difficult to verify that the routing strategy of mixed pickups and deliveries is the best among the three possible strategies. Therefore, this paper focuses on the mixed routing strategy of optimally integrating forward distribution and reverse collection. Forward distribution deals with delivering goods to demand points, and reverse collection is responsible for the picking up of previously shipped products from collection points for possible remanufacturing, recycling, or disposal. The need to handle such operations is quite common in many industries and countries; nonetheless, there exist very few related studies in the literature.