A cellular automaton model for mixing traffic in two-lane system

Based on the Nagel-Schrekenberg(NS) model,we present a mixing traffic flow model for a two-lane traffic system. In this model, the stochastic noise P in NS model is replaced by accelerating probability P-a and braking probability P-d. The fundamental diagrams of the mixing traffic under different conditions are given by the numerical simulations. We found that the lane-changing probability,the mixing rate and acceleration, the braking probability have a great influence on the mixing traffic flow. The slow cars have a decisive action on the mixing traffic.