We present a new analytical description of the cellular automaton model for single-lane traffic. In contrast to previous approaches we do not use the occupation number of sites as dynamical variable but rather the distance between consecutive cars. Therefore certain longer-ranged correlations are taken into account and even a mean-field approach yields non-trivial results. In fact for the model with $v_{ max}=1$ the exact solution is reproduced. For $v_{ max}=2$ the fundamental diagram shows a good agreement with results from simulations.
Categories: cond-mat.stat-mech