As of today, there are something on the order of 250 million cars in the United States alone. There are also around 800 million parking spaces.

Cities all over the country have “parking craters.” Many downtowns have been simply obliterated, and replaced with vast quantities of surface parking. Here’s an example — Tulsa, Oklahoma, which has the dubious honor of winning the 2013 Streetsblog Parking Crater Competition:

Here’s a visualization of the land area in Los Angeles county devoted to parking, courtesy of betterinstitutions.com:

How about the economic costs? Per Donald Shoup’s assessment, structured urban parking costs in the realm of $30,000 per spot. And perversely, in most American cities, parking is actually required to be provided, with complicated formulae depending on land use. A new residential unit might require 2 parking spaces. An office building might require one for every worker.

These policies make some intuitive sense on the surface. People driving to places have to park somewhere, right? But the real problem is that in most places, we’ve radically under-priced parking along our streets. Guess what happens when you hold the price way below the value of any good? Demand exceeds supply. So we have mostly free parking on public streets, drivers constantly circling the block looking for spots. A problem of our own making, that we address with a cure that’s worse than the disease: by mandating the provision of ever more parking spaces.

Maybe you’re thinking “sure, but businesses want to have parking — they’d probably build it even if they weren’t required to!” Maybe so. But only because we tilted the world towards driving. It’s a self-fulfilling prophecy. By requiring so much parking, and hiding its cost, we have encouraged people to drive. Just as widening roads makes traffic worse, the same holds for parking — we fear there won’t be enough space to store our cars, so we require that spaces be built. By building those spaces, we cause there to be more cars than there would have been if we hadn’t meddled in the first place.

Eventually, there’s so much parking that the places in question cease being enjoyable places to spend any time. Just look at that picture of Tulsa again. So we finally get our wish — you can find a parking spot any time you want. There’s just no place left to go when you get out of your car.

It’s a giant parking clusterfuck, and if you want to really understand it, you have to read Donald Shoup’s book The High Cost of Free Parking (affiliate link). It will completely change how you see cities.

Now, there’s no reason we can’t solve these problems even with humans driving cars. Shoup has the answer: charge the right price for on-street parking, dedicate at least some of the revenue generated to local improvements, and eliminate minimum parking requirements everywhere. It’s better for businesses, it’s better for the environment, it’s better for housing affordability, it’s better in every way you can imagine. And there are real-world examples. Old Town Pasadena, for instance, is an astounding success story for exactly these policies — utterly transformed in 10 years by an enlightened stance on parking.

But despite the successes, progress has been slow. We need a jolt. And I think we might soon have one. Autonomous driving can unlock a virtuous circle to counteract the vicious one. Here’s how it might go:

Imagine a fleet of autonomous cars. They cost something like 1/5th of the current price of a Lyft or Uber. They combine the convenience of point-to-point mobility with the price of public transportation. (Whither public transit? more on that in a future post).

It quickly becomes obvious that taking an autonomous car everywhere you would normally drive is cheaper than owning a car yourself. It’s also much more convenient — because you don’t have to — you know — actually drive. Which, if you think about it, is kind of an absurd activity. You also don’t have to park. And parking really sucks.

If we end private car ownership we effectively end the need for parking. Fleets of autonomous vehicles should be in more-or-less constant motion when demand is high. And when they’re stationary, they can easily wait in marginal places — under freeway overpasses, on the outskirts. And anyway, in cities, we should only need about 1/10th as many autonomous cars as we currently have private ones.

We can quickly begin to repurpose space that is currently devoted to storing private cars when they’re not in use to instead storing humans. Or providing for their other needs, with new restaurants, coffee shops, retail establishments, parks, etc.

More people bike and walk, for two reasons. First, because biking and walking become more pleasant. Think about how it feels to walk by an empty parking lot at night, versus a lively restaurant. And secondly, because there’s simply more stuff in the same land area. So on average the stuff you like is closer, and thus more susceptible to being walked and bike to.

As neighborhoods become more walkable and bikeable, and the value of fallow land plummets, urban infill accelerates.

But now, no one screams “don’t build! They’ll take our parking.” So the rationale for minimum parking requirements evaporates. And even with height limits unchanged, without the need for three stories of structured parking, there are simply more people on every acre of urban land.

And those people can walk to — and thus sustain — more and more local businesses.

Which make those places more of a pleasure to walk around in…etc. etc.

A virtuous circle. Healthier people; denser, better, more affordable cities; but without more miles driven. Autonomous driving holds the seeds of a dramatic urban renaissance. And I think it’s going to happen, and sooner than you might think. But not unless we work for it.

Sign up for The Autonomous Driving Revolution mailing list, and get notified of new posts and major developments in the world of autonomous cars. I’ll be back next week to discuss side effects, and how to mitigate them.