生产的发展,城市规模的扩大,城市人口的增长,造成了城市中人流多,车辆多,交通阻塞,交通事故频繁,汽车的废气和噪声污染等,已成为城市的主要公害之一。在国外己引起广泛的重视,他们除了根据交通需要来建设道路,发展新的交通工具之外,还普遍地实现城市 The development of production, the expansion of urban scale and the increase of urban population have resulted in the increase of traffic flow, more vehicles, traffic congestion, frequent traffic accidents, automobile exhaust and noise pollution in cities, and have become one of the major public hazards in the cities. In foreign countries has attracted widespread attention, in addition to their traffic needs to build roads, the development of new means of transport, but also the general realization of the city