Superblock

A superblock (Catalan superilla) groups a small grid of city blocks — classically about nine, in a three-by-three square — and removes through-traffic from the streets inside it. Cars can still reach homes and deliveries, but at walking pace; the reclaimed roadway becomes space for pedestrians, play, seating and greenery.

Barcelona popularised the modern version. Through-traffic is routed to the perimeter while interior streets drop to low speed limits, freeing up asphalt that was previously given to moving and parked cars. Most superblocks begin as tactical urbanism — a painted, temporary layout tested before anything is rebuilt in stone. The flagship Superblock Poblenou pilot cut traffic on its inner streets by 58% and roughly doubled block-interior green space. The 2018 Sant Antoni superblock followed around the renovated market hall, where the city's public health agency later measured a 25% drop in NO2.

The trade-offs are well known. Displaced cars can raise traffic on surrounding roads (Poblenou's perimeter rose modestly), rollout is slow and politically contested, and quieter, greener streets can accelerate gentrification. The reclaimed greenery also chips away at the urban heat island, but only where enough shade trees actually go in. Superblocks work best when paired with better transit and honest monitoring of where the traffic actually goes.