中文说明：
模拟多车道的交通流,车辆可以加速可以减速，同样可以换道，最后可以求出换道次数和平均车速和车流密度
English Description：
Simulation of multi lane traffic flow, vehicles can accelerate and decelerate, and can also change lanes. Finally, the number of lane changing, average speed and traffic density can be calculated