Beyond distance: Measuring spatial accessibility to healthy food for older adults in Hong Kong using a 3D least-effort method

An age-inclusive built environment is essential for promoting an accessible food landscape for the elderly population. However, previous research has focused on least-distance/time travel metrics in a 2D environment, potentially overlooking travelers' physical constraints and underestimating actual walking distances. In contrast, this study employs advanced geocomputational methods that leverage 3D building models, 3D pedestrian networks, and elevation data to appraise the fine-scale spatial accessibility to healthy food in Hong Kong. Guided by the principles of least effort, our findings suggest that 95% of older adults can access healthy food within 913.3m due to Hong Kong's compact and transit-oriented built environment. However, nearly half (47%) of older adults may encounter difficult pedestrian paths even with the least-effort route. Subsequently, the Aggregated Accessibility Index (AAI) is devised to identify communities that require improvement in promoting active living for older people. Site visits were also conducted to validate the AAI and present real-world situations to better articulate the mobility challenges imposed on older adults. Our study underscores the instrumental role of advanced spatial data computation in shaping age-friendly communities that prioritize and enhance spatial accessibility to healthy food, advocating for nuanced urban planning approaches that address the diverse needs of aging populations.