美国城市大多具有较完善的公共交通系统,属于政府的公益事业,但公共交通占据交通市场的份额除少数几个大城市外大抵都只在2%～6%的范围。自1970年代石油危机开始,美国一直致力于发展公共交通,期间共有16个城市规划新修、扩充城市轨道交通。这些轨道交通线路规划、建设的初衷一 Most of the cities in the United States have relatively complete public transport systems, and they belong to the government’s public welfare undertakings. However, the share of public transport in the transport market is only within the range of 2% to 6% except for a few major cities. Since the oil crisis in the 1970s, the United States has been committed to developing public transport. During this period, a total of 16 cities plan to newly build and expand urban rail transit. One of the original intention of these rail transit line planning and construction