Age-stratified potential accessibility to metro stations through a spatial-justice lens: Walking-cycling contrasts and spatial associations with residential demand

<title>Abstract</title> <p>Potential accessibility to metro stations (PAMS) denotes the opportunities available to residents to reach metro stations within a specified time budget and by a given access mode. It provides a basis for identifying spatial disparities in the distribution of transport resources. Few studies have jointly examined age structure, walking and cycling access scenarios, and local spatial associations between potential residential demand and PAMS within a single analytical framework. Using Hefei, China, as a case study, we constructed two-step floating catchment area (2SFCA) models for walking and cycling based on mobile-phone signalling data and route-planning travel-time matrices. We then combined Lorenz curves, Gini coefficients and bivariate local spatial autocorrelation to compare PAMS levels, within-group spatial distributions and local demand-PAMS associations. High-PAMS units were concentrated in the urban core, around interchange stations and along metro corridors. With a 15-min threshold, the share of inhabited units outside the potential station catchment fell from 82.3% under walking to 57.4% under cycling. However, medium-high or higher PAMS occurred in 22.8% of units for young adults but only 3.2% for older adults. Across the four age groups, Gini coefficients decreased from 0.7513–0.7640 under walking to 0.4690–0.4953 under cycling, indicating lower within-group spatial concentration without necessarily implying adequate access. Under cycling, the share of high-demand-high-PAMS units increased by 3.5–4.2 percentage points, whereas low-demand-low-PAMS and non-significant patterns in peripheral areas changed little. Cycling can therefore extend potential station access around the existing metro network, but its spatial benefits vary substantially by age and location. Metro-service planning should jointly consider minimum PAMS levels, within-group disparities and the persistence of low PAMS in areas of high potential demand.</p>