Equity as a Challenge of the 15-minute City in Suburban Contexts: Lessons from Madrid and Lisbon

The 15-minute city (15minC) concept has gained popularity in policy circles as a model of sustainable transportation systems, but there has not been enough empirical study done on its application to suburban peripheries with low-density residential patterns and a significant reliance on cars. In two Southern European suburban living labs—Las Rozas de Madrid, Spain, and Alverca do Ribatejo (Vila Franca de Xira), Portugal—the study examines the impact of 15minC policy initiatives on urban social equity from four distinct angles: proximity equity, modal equity, digital equity, and participatory equity. It is clear from SWOT analysis and focus group data that both study areas’ spatial layouts are geared toward promoting the use of private vehicles, which poses significant accessibility challenges for the elderly, low-income families, and the digitally marginalized population. Modal accessibility research reveals accessibility disparities of 40–60 percentage points for key amenities between walking and driving. Because digital transformation initiatives prioritize technology advancements above expanded service accessibility, they may worsen disparities in urban accessibility. Conversely, social strata whose mobility is particularly vulnerable are still not included in participation plans. It is concluded that a more redistributive transportation strategy is necessary for a fair suburban mobility transition.