Evaluating Accessibility Based on the Combined High-Speed Rail and Air Transportation Network in China

Abstract
Both high-speed rail (HSR) and air transportation networks have important impacts on accessibility to cities. However, few attempts have been made to analyze the combined modal accessibility of HSR and air, especially in the case of China. To fill this gap, this study aims to measure accessibility under a combined HSR and air transportation network in China. Average travel time (ATT), weighted average travel time (WATT), and potential accessibility (PA) are employed as indicators of accessibility. The results show that inter-urban accessibility under the combined network shows a decreasing trend from the central to the surrounding region, with the level of combined network urban accessibility significantly higher than that of either individual network. Under the ATT, WATT, and PA indicators, the combined network outperforms the HSR network by 46.53%, 47.69%, and 49.23%, respectively, and the airline network by 15.49%, 13.17%, and 75.45%, respectively. In addition, the combined network shows a more equitable distribution of accessibility than that of the HSR network.