Is distance really dying? Transportation and knowledge spillovers
利用中国高铁网络扩张作为自然实验，研究发现高铁连接后，发明人更多引用远方知识，新连接城市的创新绩效显著提升，表明交通改善降低了知识溢出的地理集中度。
Abstract Enhanced transportation infrastructure improves the frequency of travel and facilitates face‐to‐face communication. Will the resulting reduction in travel cost mitigate the geographical concentration of knowledge spillovers? Our empirical strategy exploits China's mass expansion of its intercity high‐speed railway network as a natural experiment. Using patent citations as the proxy for knowledge spillovers, we find inventors increasingly rely on more distant knowledge after rail connection and newly connect cities' innovation performance improves substantially.