Nowadays, on one hand, with the advance of citification and the extension of automobiles, traffic situation got worse every day, traffic rush turn worse, traffic accident occur more often.

• 当今社会，一方面随着城市化的进展及汽车的普及，交通环境日趋恶劣，交通拥挤加剧，交通事故频发，交通问题已经成为全球范围令人困扰的严重问题；