The close-open mixed multi depot vehicle routing problem considering internal and external fleet of vehicles

Distribution of finished goods from depots to predetermined customers and collection of goods and wastes are practical and challengeable optimization and logistics problems; therefore, appropriate management of transportation system can help companies decrease their costs and consequently earn more benefits. Several kinds of vehicle routing problems (VRPs) have been studied in the literature. In this paper, we will combine multi-depot vehicle routing problem (MDVRP) and close-open mixed vehicle routing problem (COMVRP), assuming that the fleet of vehicles is heterogeneous. Also, in this problem, contractors are used to meet a part of customers' requirements. The objective of the problem is to minimize the total cost of serving customers. To efficiently deal with the problem, a new mixed integer programming (MIP) model as well as a new hybrid metaheuristic is proposed. Moreover, analytic hierarchical process is utilized in hybridization of the genetic algorithm. The computational experiments are conducted to compare the results of HGA, GA and MIP solver, CPLEX.