The dynamics of the competition between cars and trucks on motorways

The paper studies the effects of the competition between cars and trucks on the evolution of traffic on a motorway, when transport demand increases over time while the geometric characteristics of the motorway remain unchanged, and at the same time there is a progressive adaptation of car drivers to the increase in transport cost due to the presence of trucks. A model is presented that investigates the evolution of the dynamic system by using a map that generates the sequence of car and truck flows on the motorway in successive periods of time. By examining the pattern of the trajectories in the phase space generated by the map, and the properties of the attractors and those of their basins of attractions, the paper highlights the factors that give rise to different behaviours of the dynamic system. An application of the model to five Italian motorways is presented.

Research highlights
► Traffic evolution on motorways depends on the competition between cars and trucks.
► Transport alternatives for each vehicle category affect the traffic evolution.
► The equilibrium depends on the adaptation of car drivers to the presence of trucks.
► Motorways tend to be used by only one category of vehicle in different time periods.
► Motorway specialization will be favoured by the diffusion of high speed trains.