The instability of motorway traffic

This paper presents an analysis of the dynamic behaviour of the motorway traffic system, in order to single out its characteristics that are responsible for instability. It is shown that, besides the parameters considered in the traditional car-following theory, a great importance in determining instability of a vehicle platoon is the amplitude spectrum of the speed function of the leader vehicle. The results obtained provide a theoretical validation of the reliability theoy of motorway traffic, which was founded on experimental basis, and by which the probability of instability of a traffic stream can be experimentally measured.