Beyond Proximity: Multimodal Job Accessibility Within 15–30 Min and Urban Inequality

This study examines spatial inequalities in job accessibility in Porto Alegre, Brazil, through a multimodal perspective that incorporates walking, cycling, and public transport within the 15-minute city framework. Accessibility was assessed using cumulative opportunity measures with a 15-minute travel threshold, combining open data on employment, transport networks, and demographics into hexagonal grids. Travel-time matrices were generated using the R5 routing engine via the r5r package in R, accounting for realistic multimodal routing conditions, including transfers and waiting times. The resulting accessibility measures were then integrated with socioeconomic and racial indicators for subsequent analysis. The analysis identified four accessibility profiles structured by a center–periphery divide: a low-accessibility southern periphery, a transitional northern belt with strong transit but limited active mobility, a central corridor with consistently high multimodal access, and a hyper-accessible core with exceptional walking and cycling opportunities. Income-elasticity analysis revealed stronger associations between income and active mobility accessibility than with public transport, highlighting how proximity to jobs privileges wealthier, centrally located households. High-skilled employment was concentrated in central areas, reinforcing cumulative advantages and deepening inequalities for low-income and racially marginalized populations. The findings underscore the urgency of integrated mobility and land-use policies to expand active and public transport infrastructure and decentralize employment opportunities, ensuring equitable access to jobs.