A multimodal equilibrium model with crossed congestion for simulating the urban freight distribution

Urban road networks are shared at least by three different kinds of vehicles: personal cars, buses and freight vehicles. In a previous paper (D'Acierno et al., 2002), the authors proposed a multimodal assignment model that was able to jointly simulate transit and road network, including the mode choice model inside the assignment procedure.In this paper we propose to extend the previous model to the urban freight distribution simulation, considering the crossed congestion among all three transportation systems.In this case we have to consider two origin-destination matrices: one for passengers and the other one for freights; the passenger matrix is assigned to the multimodal network while the freight matrix is assigned to the road network. The proposed assignment model allow to simulate jointly mode and route choice for passenger and route choice for freight, considering the reciprocal influences on congestion.The proposed model can be useful for simulating the real effects of urban freight distribution on urban congestion and on passenger mode choices; moreover, it can be adopted for managing the urban freight distribution so to minimise the impact on traffic congestion.In the paper a general fixed-point model will be formalised, its theoretical properties will be studied, a multimodal multiuser assignment model will be proposed and it will be tested on a real network.Future research will be addressed to adopt the proposed model and algorithm inside urban freight distribution optimization problem in order to find the distribution pattern with minor impact on urban congestion and to propose models that include among available choices also the starting time for passenger and the delivery time for freight.