How do high-speed rail projects affect the agglomeration in cities and regions?

High-speed Rail (HSR) is expected to act as catalyst for urban system restructuring for countries investing in HSR projects. This paper examines the research question regarding the HSR-agglomeration connection: to what extent does HSR spur the agglomeration of various economic activities from being near and far from the station? An analytical framework including a panel regression model, spatial autoregressive with additional autoregressive error structure (SARAR) model, and space-time autocorrelation sampling model are presented to investigate the spatiotemporal spillover effects of HSR projects on urban growth over time across cities and regions. The empirical analysis shows that, on one hand, county-level urban growth is associated with accessibility gains from HSR. On the other hand, the space-time autocorrelation patterns of NH counties decay steeply over 5 km within 3 months. The finding of this study provides policymakers with tailor-made planning strategies for connecting urban growth with HSR operations and planning.