Abstract: The simulation problem of student departing school to the traffic flow of elementary and middle school's gate road was studied by using a cellular automaton model. Based on STNS (symmetric two-lane Nagel-Schreckenberg) model, a cellular automaton model on the interference road section of elementary and middle school's gate during student departure school was established. The traffic flow characteristics of the road during student departure school time were discussed via the simulation experiment. The effects were analyzed how the proportion of students departing school by private cars, the proportion of students departing school by school buses, and the departure school time table for students of different classes affect the traffic flow and the traffic volume. The results of the examples show that the traffic jams phenomena can be suppressed and the goal of achieving largest traffic flow and decreasing the passing time of vehicles can be realized so that traffic safety is ensured by decreasing the proportion of pupils by private cars, increasing the proportion of pupils by school buses, and selecting the appropriate departure school time table for students of different classes. The correctness of the simulation model is proved.

Key words: traffic simulation, mixed traffic flow, cellular automaton model (CAM), elementary and middle school, departure school time table for students of different classes