Associations of infrastructure supply intensity and spatial inequality with economic development across Chinese cities

With the continuous development of the socio-economic, the issue of infrastructure inequality has become increasingly severe. However, the associations of infrastructure supply intensity and spatial inequality with regional economic development remain unclear. Focusing on 342 cities in China, this study uses a critical infrastructure dataset that integrates multiple infrastructure attributes. It first characterizes the spatial patterns and matching relationships of infrastructure supply intensity and spatial inequality, and then applies spatial error modelling (SEM) and geographical convergent cross mapping (GCCM) to examine their economic associations and directional relationships with regional economic outcomes. The results show that infrastructure supply intensity increases from western to eastern China, whereas cities with high infrastructure spatial inequality are mainly concentrated in northern and southwestern China. In terms of matching patterns, many western cities exhibit low supply intensity with relatively equal distribution, reflecting a form of low-level equality, while many eastern cities combine high supply intensity with significant internal infrastructure inequality. Economically, infrastructure supply intensity is consistently associated with lower economic development inequality, whereas infrastructure spatial inequality is associated with higher economic development inequality, particularly at the national scale and in the eastern region. The directionality analysis further indicates that infrastructure variables and economic outcomes contain mutual predictive information, but the dominant direction varies across infrastructure dimensions, economic outcomes, and regions. Overall, this study provides empirical support for regionally differentiated infrastructure strategies and inclusive economic development.