The Impact of City-Cluster High-Speed Rail on “Mega-Regions on Rails” through the Lens of Daily Accessibility

This study investigates the impact of City-cluster High-speed Rail (C-HSR) on the accessibility of mega-city regions (MCRs) in the Yangtze River Delta. Daily accessibility (DA) is modified from three perspectives: time buffer, competition among transportation modes, and weight. The time limit for each MCR is divided into multiple time buffers. Sub-districts are categorized into either the group that saves travel time by C-HSR or the group that wastes travel time. The weight of DA is determined by C-HSR passenger flow. DA of each time buffer and group is evaluated and compared across different MCRs and corridors. The results reveal that the time buffers intertwine. The accumulated DA of the group that saves travel time is significantly higher, but the distribution and change of DA in different time buffers vary. They can be attributed to the population and economic development of sub-districts, as well as competition between different modes of transportation.