Application of hybrid techniques to the modelling of interurban road networks

A hybrid model for interurban road network traffic is presented, which is characterized by the superimposition of two different modelling levels. The regular traffic conditions are represented by means of a macroscopic model, whereas the nonrecurrent situations are described in terms of discrete events. Apart from the originality of the application of hybrid modelling to the context of road networks, the novelty of the proposed model mainly relies on the possibility of describing the behaviour of different classes of vehicles. In particular, this is allowed by the definition of a new traffic fundamental diagram and by the introduction of interference terms into the equations describing the continuous part of the model. The presence of a discrete event modelling level enables an effective representation of the interactions among the different types of vehicles also under such unpredictable events as car accidents, traffic congestion, and critical weather conditions. The comparison between the real and the simulated evolution of some significant traffic variables is provided to give a feeling of the model experimental validation phase.