李小瑛 林祉环 侯剑华 张宇平：The pulse of urban: how cross-city metro network drives twin cities’ innovation performance in China?

       李小瑛 林祉环 侯剑华 张宇平：The pulse of urban: how cross-city metro network drives twin cities’ innovation performance in China?

       ABSTRACT

       Existing studies have examined the innovation effects of transportation infrastructure such as high-speed rail, metro systems, and highways. However, limited attention has been paid to whether and how transport linkages between neighbouring cities shape innovation outcomes. This paper exploits the opening of the Guangzhou–Foshan cross-city metro system in 2010 as a quasinatural experiment and employs grid-level data from 2006 to 2018.The results show that patent applications increases significantly in grids with metro stations in a 1-km radius. These findings are robust to instrumental variable estimation, zero-inflated negative binomial models, and some other robust check. Further analysis indicates that the innovation effects are driven by enhanced cross-city flows of capital, talent, and knowledge. Heterogeneity analysis reveals that the effects are more pronounced in Foshan, central urban areas, and industries with slower technology iteration. Overall, this study provides new evidence on the role of cross-city transportation integration in fostering regional innovation and offers relevant policy implications.

       KEYWORDS: Integration; twin cities; cross-city metro network; ‘medium-distance’ linkage;innovation; factor flow

International Journal of Urban Sciences

DOI: 10.1080/12265934.2026.2689676.