With economic growth and social progress, human society has ever-increasing demands and dependence for traffic and communication. Automobile, as one of the essential means of transportation, is acting more and more important part in promoting the flow of people and goods. With economic growth and social progress, human society has ever-increasing demands and dependence for traffic and communication. Automobile, as one of the essential means of transportation, is acting more and more important part in promoting the flow of people and goods.