This paper investigates the multi-depot vehicle routing problem with roaming delivery locations considering hard time windows. In the mentioned problem, each customer can determine several locations with a distinct hard time windows and the service provider can choose between the proposed locations to visit the customer. Also, several depots are considered for the vehicles. A mathematical model is presented for the problem. The objective function of the model is minimizing the total travel time. This objective function is important in problems that include hard time windows; because in addition to the route navigation time, it considers the waiting time of the vehicles, which is one of the integral cost factors in hard time window problems. Considering the proposed problem is NP-hard, we proposed two heuristic algorithms. Also, a hybrid algorithm based on ELS is designed to solve the problem on large scales. The results show the appropriate efficiency of the algorithm for solving small and large instances. Overall, based on the results, the proposed algorithm improved the best-known solution of two instances in the multi depot vehicle routing problem with time windows benchmark datasets.
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