Flexible parcel delivery to automated parcel lockers: models, solution methods and analysis

In this study, we introduce a logistic model for the delivery of small parcels to a set of service points (SPs), and we present effective methods for solving it. In the traditional delivery model, each recipient specifies a single location at which they wish to receive the parcel; however, when SPs are used, many recipients may have no strong preference among several locations, e.g., near the recipient's home address, near the recipient's office, or in the recipient's favorite shopping mall. If some recipients are flexible and willing to provide the sender with more than one delivery location, it is possible to perform the delivery task at lower cost and within a shorter amount of time. Our solution methods are based on the concepts of the savings heuristic, the petal method and tabu search with a large neighborhood. An extensive numerical study is conducted to evaluate our solution methods and demonstrate the benefits of our model compared to the traditional nonflexible one. We also present a simulation study to demonstrate that our model can be adapted to a stochastic and dynamic environment.