Does transportation infrastructure accelerate factor outflow from shrinking cities? An evidence from China

Shrinking cities have received increasing attention in recent years given that the emergence of these cities has raised concerns about social equity, stability and sustainability. While extensive studies have attempted to measure the structural changes from a demographic perspective, it remains unclear to what extent the development of transportation infrastructure may have influenced the formation of shrinking cities, especially considering a multi-dimensional structural change. This study fills this research gap by conducting a comprehensive impact assessment of transportation infrastructure on the development of shrinking cities in China, considering demographic, economic, and social changes. Based on the New Economic Geography theory, a novel multi-dimensional shrinking index system was developed and the characteristics of spatial distributions of different types of shrinking cities were analyzed using the GIS analysis. In particular, the impacts of two primary surface transportation modes (roadway and high-speed rail) on shrinking cities' performance were examined using a two-stage least-square model and a Difference-in-Difference model. The results confirm that both the development of roadway and high-speed rail systems have exacerbated the loss of critical factors, such as permanent population, in most shrinking cities, although the degree of impact varies by the different modes and dimensions of shrinkage. Specifically, transportation infrastructure mainly intensifies the losses of economic and social factors in shrinking cities, while the impact on demographic loss is negligible. The research findings suggest that future infrastructure investment and the strategies for urban governance should be implemented more selectively based on the different types of shrinking cities to achieve more sustainable and resilient urban development.