University of California Transportation Center

This paper demonstrates how the constraints of overnight delivery affect the design of pickup and delivery systems. Cost depends on the number of vehicle routes needed to pickup and deliver shipments. This number in turn depends on the critical parts of the driver's day: the morning delivery period, up to the delivery deadline, and the afternoon pickup period, after the cutoff time. Pickup routing is the more complicated, due to the dynamic nature of customer calls. Models are developed to assess the workload remaining to be completed at the cutoff time and, from this value, the number of routes required to pick up the shipments.