The vehicle routing problem in urban networks: an approach based on a network fundamental diagram.

This paper presents a formulation of the vehicle routing problem (VRP) based on the concept of a network fundamental diagram (NFD). The proposed model for estimating the (weighted) link costs considers variables describing the average traffic conditions related to homogeneous portions of the network. They are synthetized in a NFD. The proposed VRP computes the optimum path between each couple of clients by taking into account link costs and average values of density, which may be considered as proxies of travel time reliability. An application to a real dimension network allowed the testing of the proposed method.