Does the construction of an integrated transport network promote urban innovation? A perspective based on the theory of flow space

Transportation infrastructure, which has always been regarded as an important element to promote regional innovation, accelerates factor flows and productivity spillovers. In February 2021, the State Council of China issued the outline of national integrated multidimensional transportation network planning (2021–2050), which proposed that during the 14th Five-Year Plan period, the Yangtze River Delta would speed up the construction of an integrated transport network to serve the dual circulation development pattern in China. However, few studies have systematically investigated the development of integrated transport in the Yangtze River Delta, especially the relationship between transport operating efficiency and regional innovation based on the theory of flow space. This study aims to calculate the integrated transport efficiency of 26 cities in the Yangtze River Delta and analyse the spillover effect of efficiency improvement on urban innovation. The results reveal that integrated transport efficiency is relatively stable at approximately 0.92. We find that the local innovation value would increase by 0.119% with every 1% increase in transport efficiency, and it would exceed 0.26% after introducing spatial factors. The spillover effect on the surrounding cities is significantly higher than that in the cities themselves, and the result is 0.292 under the economic spatial distance weight matrix. These findings will support the construction of the integrated transport network and provide useful references for government decision makers in the Yangtze River Delta.