Multi-depot pickup and delivery problems in multiple regions: A typology and integrated model

The rapid development experienced by the transportation industry in the past decades has led to many configurations of networks and therefore to an explosion of variants in transportation problems, motivating researchers to look at broader logistic problems, beyond the basic vehicle routing problems. This work introduces a new type of problem scenario combining various attributes: a pickup and delivery problem with multiple regions, multiple depots, and multiple transportation modes. We provide definitions, a literature review, and a step-by-step construction of the mathematical models from a simple and well-known scenario to the multiregion multidepot pickup and delivery problem (MR-MDPDP). For each step the relevant literature is examined. Furthermore, we suggest possible extensions for prospective research.