Transforming a busy road into a public open green space in Bilbao, Spain

Key Learnings

• Improving air quality: Greenery at one of Bilboa’s most polluted roads, close to the city gateway, has significantly reduced the daily number of cars, improved air quality and the surrounding environment.
• Permeable surfaces: Sustainable Urban Drainage Systems, with better water retention capacity compared to conventional solutions, have increased the permeable surface area and reduced the risk of flooding during heavy rain.
• New public space: Allocating roads to public spaces for local citizens has increased public empowerment and shifted priorities from privately owned vehicles to community spaces and democracy.
• Green infrastructure design: Green infrastructure such as trees, shrubs and green spaces, improves air quality but also provides other services to local residents. Its implementation requires a thought-through design to benefit largely from it. Tree location, light reflection and solar radiation, material selection, shade and many more influence outdoor space quality, thermal comfort and citizen wellbeing.

Summary

In Bilbao, Spain, a major urban adaptation project transformed Mª Díaz de Haro street, a heavily trafficked road, into a green public corridor to address climate risks such as flooding and urban heat. By replacing asphalt with permeable surfaces, expanding green infrastructure, and reallocating space to pedestrians, the project significantly improved air quality, reduced flood risk, and enhanced thermal comfort. These changes also promoted citizen engagement and public well-being. Post-implementation assessments confirmed reduced perceived temperatures and greater resilience to future climate conditions. Public acceptance has been strong, and the initiative underscores the importance of treating green infrastructure as a functional climate service, not just ornamental greenery.

Contact

Mikel González Vara; mgvarabilbao [dot] eus (mgvara[at]bilbao[dot]eus)