A multi-depot pickup and delivery problem with a single hub and heterogeneous vehicles

This paper introduces a special kind of multi-depot pickup and delivery problem. In contrast to the general pickup and delivery problem (GPDP, see e.g. [19, 31]) all requests have to be picked up at or delivered to one central location which has the function of a hub or consolidation point. In hub transportation networks routes between customers and the hub are often short, i.e. involve only one or very few customers. The reason for this can been seen in narrow time windows as well as in high quantities which make it possible to fully load a vehicle at one customer. Thus, the focus here is on problems where all possible routes can easily be enumerated, i.e. the problem primarily considers the assignment of transportation requests to routes. We assume that many problems in transportation logistics can be modeled and solved similarly whenever routes can be enumerated and the temporal aspects of transportation requests are important.