Inequality, Bi-Polarization and Mobility of Urban Infrastructure Investment in China’s Urban System

In periods of rapid urbanization, investment in urban infrastructure should not only meet the increasing demands of all urban people, but also be equally allocated between cities to achieve social equity and sustainable development. This paper aimed to conduct quantitative research on the unbalance of urban infrastructure investment between cities in China. The measurement models for inequality, bi-polarization and the mobility of urban infrastructure investment were constructed by means of the Gini coefficient, bi-polarization index and mobility function from the urban system, and an empirical study was conducted based on panel data from 2006 to 2014. The results show that: (1) The overall inequality of urban infrastructure investment in China’s urban system was relatively prominent and showed a “U-shaped” change generally. (2) The inequality between different administrative levels or regional cities only partially accounted for the overall inequality of China’s urban system. (3) Inequality and bi-polarization showed inconsistent performance. (4) Mobility played a positive role in reducing the inequality and bi-polarization. Based on the empirical findings and the reality of China’s urban infrastructure investment and financing, targeted policy suggestions were proposed in terms of adjusting inequality and bi-polarization, innovating investment and financing mechanisms, and optimizing urban infrastructure investment strategies.