A procedure for an integrated network and vehicle routing optimisation problem

In this paper, an integrated Network and Vehicle Routing Optimisation Problem (NVROP) for freight vehicles is proposed. The variables involved in the problem are discrete (link topology, routes for freight vehicles) and continuous (link capacity in term of signal settings). The discrete variables are related to the link direction, lane numbers, lane use and sequence of retailers reached by the vehicles. The continuous variables, assuming that the link capacity is a function of the characteristics of the final node in the link, are related to the regulations at the intersection. The NVROP is, hence, formulated as a mixed (discrete/continuous) problem in a congested network. A heuristic procedure is used both to find the best network configuration and the best vehicle route.