Air Transport versus High-Speed Rail: An Overview and Research Agenda

Table 9

The competition and cooperation effects between air transport and HSR on environment and social welfare.

References	Region	Time frame	Comp.	Coop.	Data type	Main results
[22]	—	—			Analytical	If HSR is not sufficiently greener than air transport, the introduction of HSR will increase the environmental pollution and reduce social welfare; otherwise it will increase the environmental benefit. When the increase of the emission of HSR due to the increased speed is sufficiently high, the competition would be detrimental to the environment.
[5]	US	—			Analytical	There are cases with significant HSR penetration; the national long-term CO2 emissions and costs could be decreased.
[46]	US	—			Mix	The greenhouse gas emissions could be reduced in US with HSR.
[23]	—	—			Analytical	The welfare is improved with low substitutability; when the substitutability is high, the cooperation would improve the welfare if the hub airport is heavily capacity-constrained.
[47]	—	—			Analytical	The cooperation could improve the welfare of international passengers.
[48]	Madrid-Malaga route	—			Analytical	The welfare would be very likely to be enhanced for airports with capacity constraints. The environmental effects could be positive or negative.
[49]	Worldwide	2010			Empirical	Mode substitution from air to rail is likely to play a greater role in the air pollution reduction around airports.
[50]	Madrid Barajas airport	—			Mix	With HSR, passengers traveling with aircraft and private car are reduced, leading to environmental benefits. Increasing the travel cost of private car is picked up by air transport rather than HSR, leading to negative environmental impacts.
[51]	US	—			Mix	A HSR system with current technologies would provide significant environmental benefits over existing modes, when the ridership is high.
[52]	London Heathrow airport	—			Analytical	Significant savings (delays and costs) can be obtained even with rather modest substitution.
[53]	JP	1999–2007	—	—	Mix	The operation of aviation industry is socially efficient in the observed period, although its CO2 emission per passenger kilometer is higher than the one with rail.
[54]	27 EU countries	2020 (scenarios)			Analytical	Development of the HSR network across Europe should be encouraged in order to maximize the overall social welfare.
[31]	London Heathrow airport	—			Empirical	Increased connectivity and catchment area, improved accessibility, and reduced local air pollution.
[55]	—	—			Simulation	The level of passengers delays would be increased with intermodal passenger movement, while social benefits can be expected at airports with large amounts of short haul flights.