Lewis Mumford was suspicious of parking. “The right to access every building in a city by private motorcar,” he wrote in The City in History, “in an age when everyone owns such a vehicle, is actually the right to destroy the city.” Jane Jacobs, who disagreed with Mumford on many counts, agreed here. Parking lots, she said in The Death and Life of Great American Cities, were “border vacuums”: inactive spaces that deadened everything around them.

Mumford and Jacobs published those lines in 1961, when most United States cities were 15 years into an experiment called “minimum parking requirements”: mandates in zoning codes that forced developers to supply parking on-site to prevent curb congestion. In postwar America, development was booming, and neighbors were worried that new residents would make street-parking impossible. Decades later, parking requirements still exist nationwide. In Los Angeles, where I live, new apartment buildings must have at least one parking space per unit; retail buildings need one space per 300 square feet; and restaurants need one space for every 100 square feet of dining area.

Parking requirements enforce what Mumford decried: the right to access every building by private car. As Mumford predicted, they have been a disaster. American urban history is stained with tragic missteps and shameful injustices, so parking requirements are hardly the worst policy cities have tried. But they are notable for how much needless damage they have caused, over a long period, with few people even noticing.

The trouble with parking requirements is twofold. First, they don’t do what they’re supposed to, which is prevent curb congestion. Because curb parking is convenient and usually free, drivers fill up the curb first, no matter how much off-street space exists nearby. Second—and more consequential—parking requirements attack the nature of the city itself, by subordinating density to the needs of the car.

Cars revolutionized transportation by promising not just speed, but autonomy. Cars let you go wherever you want, whenever you want, by yourself and by a route of your choosing. But that promise is fulfilled only if everywhere you might go has a place to store the car whenever you arrive. A train drops a passenger off and keeps going. A driver drops a car off and keeps going. Thus most trains are mostly moving, while most cars are parked most of the time. The price of the car’s convenience, then, is the space it consumes when it isn’t in motion, and indeed even when it isn’t there. Cities designed for cars must set aside space: space to wait for cars, and space to hold them while they wait for their drivers to come back.

Parking minimums take the cost of that space—a cost that should be borne by drivers—and push it onto developers, hiding it in the cost of building. Sometimes this means a project can’t be built at all. At other times, it makes projects more expensive: In downtown L.A., parking usually costs developers more than $50,000 per space to build. Walt Disney Concert Hall, a cultural landmark that is home to the Los Angeles Philharmonic, cost $274 million to build. Of that total, the underground parking structure, which is not a cultural landmark (it’s an underground parking structure), accounted for $100 million.

Because parking requirements make driving less expensive and development more so, cities get more driving, less housing, and less of everything that makes urbanity worthwhile. This process is subtle. Many mayors today declare their support for walkable downtowns and affordable units. But cities are built at the parcel, not from mayors’ podiums. And parcel by parcel, the zoning code quietly undermines the mayors’ grand vision. A commercial requirement of one parking space per 300 square feet means developers will put new retail in a car-friendly, pedestrian-hostile strip mall. And a requirement of one parking space per 100 square feet for restaurants means the typical eating establishment will devote three times as much space to parking as it will to dining. America did not become a country of strip malls and office parks because we collectively lost aesthetic ambition. These developments are ubiquitous because they are the cheapest way to comply with regulations.