城市扩张对公共交通供给影响——来自中国地级市的实证证据

The Impact of Urban Expansion on the Efficiency of Urban Public Transport Supply:Evidence from Prefecture-level Cities in China

伴随中国城市化的快速推进,城市郊区外圈逐渐出现了外延式扩张现象,城市扩张现象作为城市化过程与公共交通基础设施建设密切相关。基于2009—2017年中国地级市的道路公共交通系统数据,结合非参数DEA-malmquist方法计算不同城市的公共交通供给效率,探讨中国城市扩张的外部性对于城市公共交通供给效率的影响,并对不同地区城市扩张对公共交通供给效率的影响进行异质性分析。创新点在于,关注城市扩张对城市交通供给这一直接影响机制,并着眼于城市公共交通基础设施建设;以全国城市为研究对象进行实证分析,避免了以往相关研究以省级或单个城市、区域为研究对象可能造成的估计偏误;使用工具变量法克服由于反向因果关系或缺乏对遗漏变量的考虑所导致的内生性问题,对因果关系进行更加清晰的识别。结果显示:(1)城市扩张现象在我国中西部、东部地区显著存在,东北部地区城市扩张现象不明显,且内部差异最小;(2)总体上城市扩张显著提升了城市公交供给效率;(3)其影响效应在我国不同地区存在明显差异,在我国东部和中西部地区城市,城市扩张对于城市公交供给效率存在正向显著作用,但在东北部地区的影响并不显著。

Along with the rapid urbanization in China,the phenomenon of outward expansion of the suburban outer circle gradually emerged,and the urban expansion as an urbanization process is closely related to the construction of public transportation infrastructure.Based on the public transportation data of Chinese prefecture-level cities from 2009-2017,the article uses the nonparametric DEA-malmquist method to calculate the public transportation supply efficiency of different cities to explore the impact of externalities of urban expansion on urban public transportation supply efficiency in China.The heterogeneity analysis of the impact of urban expansion on public transportation supply efficiency in different regions is also conducted.The article is innovative in that it focus on urban expansion as a direct influence mechanism on urban transportation supply and focus on urban public transportation infrastructure development;it takes cities as the research object for empirical analysis,avoiding the estimation bias that may be caused by previous related studies taking provincial level or individual cities or regions as the research object;it uses the instrumental variable method to overcome the endogeneity problem caused by reverse causality or omitted variables,and to provides clearer identification of causality.The results of the study,(1)the phenomenon of urban expansion is significantly present in the centralwestern and eastern regions of China,while urban expansion is less pronounced in the northeastern region and has the least internal variation;(2)in general,urban expansion is conducive to the improvement of urban bus supply efficiency;(3)after controlling for the omitted variables bias and endogeneity problems,the result still imply that the most cites’public transport supply is exacerbated in the process of urban expansion,and the regional sample analysis indicates that impact effect is obviously different in different regions of China.