Dynamical Universality Class Of The Nagel-Schreckenberg And Related Models

Models for vehicular traffic fall into distinct dynamical universality classes of non-equilibrium systems. Such models share model-independent aspects of their dynamics, such as current fluctuations. Up to now the universality class of the Nagel-Schreckenberg (NaSch) model was not known except for the special case v(max) = 1. In this case the model corresponds to the ASEP (asymmetric simple exclusion process) which belongs to the Kardar-Parisi-Zhang (KPZ) class characterized by the dynamical exponent z = 3/2. We have shown that the NaSch model for general v max also belongs to the KPZ class. Here we demonstrate that the universality class is not changed by extending the model to a two-lane NaSch model with dynamical lane changing rules. As an application we estimate the relaxation time to the (generally unknown) stationary state.