It seems counterintuitive that shrinking a four-lane arterial by one lane would improve traffic conditions or that what’s good for traffic is simpatico with pedestrian-friendly design. But with geometry on its side and data showing that road diets—like the one that slimmed Nickerson Street in 2010—are a win-win, the Seattle DOT is now turning to the Central District’s major north-south corridor, 23rd Avenue. The mission of the approximately $40 million revamp: Transform the highway-style design into a smart street.

The Tetris logic is simple: Removing a full lane gives pedestrians bigger sidewalks, and converting another into a dedicated turn lane unclogs traffic by preventing left-turn backups and lane-change jockeying. Added benefit? The plan also uses the extra space to create pit stops where buses can get out of the way while stopping to pick up riders.

For those who think urbanism is about favoring one mode of transportation over another, let this car-ped-bus plan serve notice: The guiding principle of city design is mixed use.