The Substitution Effect of High-Speed Rail on Civil Aviation in China

China's high-speed rail (HSR) network has had a marked effect on civil aviation transport and CO2 emissions. We conduct a quantitative analysis of the substitution effect during the period 2008-2017 using the difference-indifference method. We find that (1) the introduction and operation of the HSR network of four vertical and four horizontal lines has had a significantly negative effect on the civil aviation service. Overall, the numbers of passenger flights and air passengers fell by 28.7% and 31.8%, respectively, following the introduction of HSR. (2) HSR is most competitive when trip or operating times are less than 4 h (3) For operating times within 6 h, or trips of about 1400 km, HSR enjoys an obvious competitive advantage over civil aviation. (4) Planning is underway for an expanded HSR network comprising eight vertical and eight horizontal lines. On completion, an additional 833 flight routes compared with the current HSR network and the rate of substitution of HSR for civil aviation flights will increase by 8.8%. Taking into account an increase in rail speed for passages along rivers and coastal areas, the substitution rate of HSR will increase by a further 0.7%. (5) HSR development will have obvious CO2 emissions reduction effect on aviation transport.