Quantification of walkability in terms of sustainability

Often promoted as a key to greener cities, walkability is widely praised for its sustainability, yet the extent to which it can be considered truly sustainable remains unclear. Despite its growing prominence in urban planning and policy, the true environmental, social, and economic impacts of walkability remain largely assumed rather than rigorously quantified. This perspective examines walkability through the three sustainability pillars, highlighting both its potential benefits and its overlooked trade-offs. Rather than treating walkability as an inherently sustainable solution, this perspective frames it as context-dependent, shaped by urban form, climate conditions, infrastructure design, and patterns of use. By synthesizing existing sustainability assessment tools and frameworks, including life cycle–based, social, and economic evaluation approaches, the perspective outlines pathways for more rigorous, holistic, and data-driven evaluations of walkability. Such approaches are essential for equitable, environmentally sound, and economically viable urban policies, and ensure that walkability meaningfully contributes to long-term urban sustainability.