Abstract: This paper uses GIS to calculate the demand substitution effect of high-speed rail on aviation and highway after the completion of the "eight vertical and eight horizontal" high-speed rail network, and to quantitatively evaluate the impact of high-speed rail network on travel efficiency and environmental benefits. The results show that high-speed rail has a significant substitution effect on highway and aviation, replacing 31.65% of the road market share and 12% of the aviation market share. The elastic coefficient of high-speed rail is much larger than the that of aviation and highway, and is the only one greater than 1. More importantly, the construction of the high-speed rail network will trigger the effect of "cut-off". Among aviation and highway, 50.4% of the reduced passenger volume and 46.1% of the reduced turnover volume are attributed to the "cut-off" effect. High-speed rail can also improve travel efficiency and enhance environmental benefits by reducing the total carbon emissions in the operational stage. Different from previous studies on single high-speed rail lines or local areas, this study takes the global network between 337 prefecture-level cities in mainland China as the research object and considered the multi-modal transportation network including aviation, highways, and high-speed rail. Therefore, the results are more realistic.

Key words: Intercity Traffic, "Eight Vertical and Eight Horizontal"Network, High-speed Rail Network, Aviation, Highway, Multimodal Transportation, Nationwide Network, Substation Effect, "Cut-off" Effect, Number of Tourists