  We propose a stochastic cellular-automaton model for two-lane traffic flow
based on the misanthrope process in one dimension. The misanthrope process is a
stochastic process allowing for an exact steady-state solution; hence we have
an exact flow-density diagram for two lane traffic. In addition, we introduce
two parameters that indicate respectively driver's driving-lane preference and
passing-lane priority. Due to the additional parameters, the model shows a
deviation of the density ratio for driving-lane use and a biased
lane-efficiency in flow. Then, a mean-field approach explicitly describes the
asymmetric flow by the hop rates, the driving-lane preference, and the
passing-lane priority. Meanwhile, the simulation results are in good agreement
with an observational data, and we thus estimate these parameters. We conclude
that the proposed model successfully produces two-lane traffic flow
particularly with the driving-lane preference and the passing-lane priority.
