当前中国城市公共交通面临着一系列的挑战:　城市人口的增长;私人汽车拥有量的增加;城市交通拥挤日益严重;石油价格的增长与公共交通运营成本的提高;公交补贴日益萎缩;城市居民对公交的依赖程度日益降低。如何构筑合理的、具有竞争力的城市公共交通体系,尽量降低居民的出行费用 At present, the urban public transport in China faces a series of challenges: the growth of the urban population; the increase of the private car ownership; the increasing traffic congestion in the cities; the increase of the oil price and the increase of the operating cost of public transportation; the shrinking of subsidies for public transport; Bus dependence is decreasing day by day. How to build a reasonable and competitive urban public transportation system to minimize the travel expenses of residents