Comparative environmental performance of high-speed rail and air transport on Japan's domestic short-haul routes: A case-based evaluation using EUROCONTROL's IMPACT

Air transportation offers significant speed advantages, particularly on medium- and long-haul routes, yet it contributes disproportionately to environmental pollution, especially on short-haul domestic flights. In contrast, high-speed rail (HSR) represents a more sustainable alternative. This study examines CO2 emissions from narrow-body and wide-body aircraft in comparison with Shinkansen trains on selected Japanese domestic routes, where air and HSR services directly compete, focusing on the Haneda–Osaka and Haneda–Fukuoka corridors. Japan is notable for having the highest use of wide-body aircraft on domestic routes worldwide, which makes this context particularly relevant for examining the environmental impact of aircraft type. Emission data for each aircraft type were obtained using the integrated aircraft noise and emissions modeling platform (IMPACT) developed by EUROCONTROL. The results indicate that wide-body aircraft emit at least twice as much CO2 as narrow-body jets, highlighting the critical influence of aircraft type on short-haul emissions. Shinkansen trains, particularly the N700 series, demonstrate the lowest per-passenger emissions, achieving approximately 20% greater efficiency than the older 700 series. The study provides policymakers with a meaningful perspective, emphasizing that deploying wide-body aircraft on short-haul routes is inconsistent with environmental sustainability goals.