Our paper (joint work with Alina Dragomir and Karl Dörner):

The pickup and delivery problem with alternative locations and overlapping time windows

Is now published in Computers & Operations Research and can be downloaded here.

Motivated by some real-life last mile challenges, we study a variant of the PDP, in which both seller and buyer can specify their daily itinerary. An itinerary is a detailed plan of places scheduled for visit during the day and the estimated time frame. The carrier can then choose between different locations and their corresponding time windows for pickup and delivery of the parcel to minimize its transportation cost. It can be very expensive for the transporter, even infeasible, to allow a single customer-selected pickup and delivery time window. However, having more than one option spread throughout the day makes the problem both easier to solve and cheaper in terms of transportation cost. The option of multiple locations counterbalances the restricted consolidation potential.