Route choice on freight networks with concave costs and exclusive arcs

An exclusive arc carries flow for just one origin-destination pair. A shared arc carries flow for more than one origin-destination pair. This paper shows that the optimal route for each origin-destination pair can be found from the optimal flows on the shared arcs alone. The optimal shared arc flows can be found with an exhaustive search over the feasible region for these flows. Because logistics networks can often be reduced to independent subnetworks, each with a small number of shared arcs, the procedure should have wide application.