More than 40% of the street network in some cities is suitable for transformation similar to Barcelona-style “superblocks,” according to a new study. The findings highlight the possibilities as well as the complexities of making neighborhoods in diverse cities greener and less car-centric.
Superblocks are a relatively new urban planning concept that has been pioneered in Barcelona, Spain. The basic idea is to identify a 3 x 3 grid of 9 city blocks and restrict vehicle traffic to the streets on the perimeter. The interior streets then become available for walking, biking, and expanded green space.
It’s an appealing idea to foster urban sustainability and livability. But not all cities have the regular, rectilinear street grid that characterizes large parts of Barcelona. Can the concept work in cities with other urban forms?
The new study suggests the answer is yes—at least sometimes. “For many cities, the urban layout allows similar urban re-design strategies, even if the city is not a perfect model of the grid-like layout,” says Sven Eggimann, a researcher focusing on sustainable urban planning at the Swiss Federal Laboratories for Materials Science and Technology in Dübendorf, who conducted the analysis.
Eggimann used a computer algorithm to analyze data from the open-source geographic database OpenStreetMap and automatically detect areas with the superblock potential. He applied this analysis to 5 km x 5 km areas of the city center in 18 different cities around the world.
His analysis also identified locations suitable for “miniblocks,” or 4 city blocks arranged in a 2 x 2 grid, and “linear” blocks, meaning a single street bordered by 2 blocks. Such arrangements might not provide all the benefits of a superblock, but could be a starting point on which eventual superblocks could build, Eggimann suggests.
More than 40% of the street network is suitable for integrating into superblocks or miniblocks in some cities, Eggimann reports in the journal Nature Sustainability. The potential is greatest in cities that have grid-like layouts similar to Barcelona’s, such as Madrid and Mexico City.
But “having a grid-like street layout might not be the only criteria” for superblock suitability, Eggimann cautions. Atlanta, Georgia has a grid-like city structure, but only a few percent of its streets are suitable for superblocks, largely because urban density is too low (and therefore doesn’t facilitate public transit as an alternative to the cars that would be excluded from superblocks, for example).
What’s more, cities with irregular street layouts can sometimes support a generous smattering of superblocks and miniblocks, the analysis suggests.
Excluding cars from the insides of superblocks and miniblocks has the potential to snarl traffic and reduce support for these urban design changes. So Eggimann applied another algorithm to the OpenStreetMap data to assess the degree to which potential block sites would be disrupt existing traffic patterns. This “could help to initiate a transformation with the least disruptive sites,” Eggimann says.
The full benefits of superblocks would probably require them to be implemented widely at city scale. This, in turn, would require other changes such as redesigning the public transportation system (in fact, some bus routes have been rejiggered in Barcelona).
But superblocks are only one approach to urban transformation, Eggimann says. Even cities that right now don’t seem particularly suitable for superblocks (or even miniblocks) could implement things like temporary or seasonal pedestrian streets or reducing the number of parking spaces or the number of traffic lanes, for example—actions that might catalyze bigger, more permanent changes in the future.
Source: Eggimann S. “The potential of implementing superblocks for multifunctional street use in cities.” Nature Sustainability 2022.