Quasi-experimental evaluation of public space quality of Barcelona’s Superblocks Green Axis

Urban greening and traffic calming are promoted as population-health strategies, yet objective empirical evaluations remain scarce. Barcelona’s Superblocks Green Axis redesigned streets and created new squares in Eixample district (2022–2024) to prioritise pedestrians, greenery and social life. We assessed whether this intervention improved public space quality as key health determinants supporting healthier and more inclusive urban living. We conducted a quasi-experimental before–after study with a comparison group. The intervention comprised seven street segments and four new squares (≈102,000 m²); the comparison included two nearby street segments. Public space quality was assessed pre- (May 2022) and post-intervention (January 2024) using an ad hoc 41-item tool covering eight dimensions: architectural characteristics, natural areas, facilities, maintenance and cleanliness, environmental characteristics, attractiveness and comfort, safety, and social aspects. Net effects were estimated using difference-in-differences (DiD) analyses. DiD analyses show significant changes in natural areas (+4.94 points), maintenance and cleanliness (+2.55) architectural characteristics (+2.28), safety (+1.61), and environmental characteristics (+1.00) contrasted with the comparison street. These improvements reflect increased greenery, pedestrian-priority space, and accessibility and reduced traffic-related exposures likely to benefit more vulnerable populations groups, such as older adults, children or people with mobility limitations. This evaluation provides empirical evidence that street redesign can substantially improve health determinants. From an equity perspective, reducing traffic exposure and enhancing accessible, safe and attractive public spaces may foster more inclusive daily mobility and social interaction, while potential adverse effects such as gentrification should be monitored. These findings support scaling up alongside equity-oriented governance and evaluation.

Key messages

• Green Axis Street redesign substantially improved public space quality, especially greenery, safety and pedestrian conditions, through a quasi-experimental evaluation.

• By reducing traffic exposure and improving access and safety, Green Axes promote inclusive daily mobility and social street use, contributing to urban health equity.