City-pair air connection under high-speed railway development: Simulation of air travel demand affected by the new Chinese high-speed rail lines opening in 2030

High-speed rail (HSR) is increasingly challenging air transport operations in China due to its competitive edge in frequency, better accessibility from city centers (in particular when considering door-to-door travels), and overall convenience for short to medium distance travel. This increasing demand changes will become even more extensive in the next decades with laid out high speed rail development plans. By the end of 2020 the railway network of China had expanded to include around 40.000 km of HSR lines (equal to 2.2 times the extent of 2013) and the milestone for 2030 until 2050 is to reach more than 70.000 km of HSR lines. Accordingly, airlines are under increasing pressure to adapt their networks in order to be efficient and profitable. In this study, we develop a demand forecasting model with the goal to analyze the effect of increased high-speed railway penetration on air markets passengers flows from 2012 to 2019 and predict what will be the impact for the domestic aviation sector for the next two decades with the new railway lines planned to be opened by 2030. We propose and compare different econometric specifications, highlighting the advantages of using a declination using a semi-logarithmic OLS to predict the total city-pair market demand, reaching an accuracy of around 80% when validating the model on an unseen set of test data. Specifically, our analysis evaluates the air demand shift towards rail in city pairs that will benefit from new HSR lines opening in 2030. Our results show that for the majority of cities connected below 550 km, the air transport will likely be replaced by the HSR connection by 2050, while for cities connected between 550 and 2000 km of distance the air demand will substantially decrease but without completely disappearing. Moreover, the results clearly show the relationship between distance and the introduction of HSR: the closer the origin and destination cities, the sooner the majority of passengers demand shift from air transport to HSR. Our research contributes to the discourse on sustainable transportation planning, highlighting the potential implications for policymakers, urban planners, and transportation industry stakeholders.