Advancing facility accessibility analysis across hierarchies and scales in mainland China

With rapid urbanization and the expansion of national transportation system, versatile service facilities have emerged, ranging from urban services meeting daily needs to national facilities catering to specialized demands. Ensuring efficient and equitable access to multi-level facilities is critical for promoting a nation's sustainable development. Despite extensive research on urban facility accessibility, an integrative assessment of multi-level facility access—particularly inter-regional access to national facilities—remains underexplored. To fill this gap, this study proposes a nationwide hierarchical classification system, categorizing facilities into three levels—urban, provincial, and national—based on service range and spatial distribution. Tailored accessibility calculation methods are developed for each level, incorporating road, rail, and air transport. Results from mainland China reveal stark disparities across facility levels: Urban healthcare services exhibit the highest accessibility but significant spatial inequality, whereas national-level theme parks show the lowest accessibility yet the highest spatial equality. Additionally, accessibility determinants display a hierarchical pattern: facility density dominates urban facility accessibility, while administrative area size and GDP govern access to provincial and national facilities, respectively. Furthermore, HSR and air transport enhance access to national facilities while reducing inequality. These findings provide actionable insights for optimizing facility distribution and accessibility across hierarchical spatial scales.