Does high-speed rail complement or substitute other transportation modes? City-level evidence from China

China has been the world's largest high-speed rail (HSR) country, with a total length of over 40,000 km. While the literature has widely examined various effects of HSR, it is still rare to examine its aggregate transportation effect and the effects on road transportation. We constructed panel data from 256 Chinese prefectural-level cities between 2001 and 2019 and estimated the transportation effects of HSR using a difference-in-differences approach. Our results reveal that HSR connection does not have a significant effect on overall and highway transportation outcomes, but it increases railway passenger volumes by 36.3 % and reduces airport freight and passenger throughputs by around 45 % and 80 %, respectively. Further studies show that HSR complements highways to improve passenger transportation and substitutes conventional trains for transporting passengers. HSR also reduces buses by about 11 % but increases taxis by about 7 %. These results suggest that HSR plays more in substituting other transportation and restructuring China's transportation system.