“San Francisco is going bananas for new housing, and Manhattan is always looking for space, and here we have this sitting in front of us,” Samaras says. “That’s what autonomous vehicles can do.”

There are some big speed bumps on the road to a low-parking future, though. That’s because most of these rosy projections assume self-driving cars are likely to be deployed en masse by ride-sharing firms that would use them with deep efficiency, offering such convenience and cheapness that we’d all ditch our personal vehicles.

But there’s another route the future might take. Shannon McDonald, an architect and historian of American parking, recently got a glimpse of it. She flew to Baltimore to visit her brother, who picked her up in his new car. It included several self-piloting features; he showed her how it wouldn’t let him steer accidentally into a neighboring lane on the highway, and when he got home, the car parallel parked itself. Such features might make self-driving cars so alluring that everyone wants one.

“What if they’re all privately owned? You’ve got a driverless vehicle, and maybe you don’t share it,” McDonald tells me. If her brother and sister-in-law had a fully self-driving car, maybe they’d decide to go to New York to see theater. It’s a crazy-long five-hour drive, but who cares? They could kick back. They would “ride all the way in and sleep in it all the way back,” she says. If you can read, watch TV, work and do email, or catch up on sleep while your car steers, the sting goes out of commuting.

In this version of the future, self-driving cars could smash through the Marchetti Wall. They would unlock what’s known as “induced demand”—prompting commutes of such lengths that they’d have been previously unfathomable. Or we might find people deciding they never need to park their cars because, hey, cars can circle on their own.

McDonald imagines a commuter going to work in his self-driving car: “Let’s say he gets to the office, he gets dropped off at the front door. And he tells the car to go find its cheapest parking.” Maybe it drives out to the far suburbs, to park for free on a side street. “He says, ‘Okay, just go have fun today! Go drive around! Come back and get me at five. Why not? It’s cheaper!’” The problem of cruising could morph into a Monty Pythonesque parody of modern life: a street clogged with traffic, but all the cars are empty. In economic terms, this is called a “rebound effect”: If you make something suddenly more efficient to do, people will do more of it.

Urban and traffic thinkers are divided about how serious these negative impacts could be. Many suspect the Marchetti Wall will remain in place. “We’re unmoved by these arguments,” says Berkeley Lab’s Greenblatt. “Because seriously, most people are not going to sit in a car for hours a day.” Others agree, pointing out that the generational shift away from owning a personal car isn’t likely to dim. Most experts I spoke to said governments should set policies that make fleet-based ride-sharing more appealing than individual car ownership. The main lever here is “congestion pricing”: A city could—as London already does—require drivers to pay extra fees to travel in the congested downtown areas unless they’re in ride-shared vehicles. Nearly every expert I spoke to advocated some version of congestion pricing to prevent a rebound effect.

If cities leave self-driving cars entirely to the private sector, they court risk.

Others pointed out that personal ownership might well blur with fleet ownership. If someone owned a self-driving car, she might opt to make money off it by having it drive off to work for a fleet when she’s at the office. Cities could also offer incentives to ride-sharing services that augment public transit, feeding people to major subway and rail lines. (This is already a trend: Uber reports that in some cities, one-third of its trips begin or end at a public-transit station.)

The bottom line is, if urban officials want to make sure these technologies benefit civic life, they need to start talking about them now. “If we want it to be sustainable, the city has to get involved in these services,” says Tom Radulovich, executive director of Livable City, a nonprofit transit group. Cities could deploy their own fleets of subsidized self-driving cars—the next generation of public transit—aiming them particularly at the mobility disabled and underserved and low-income areas, where residents often lack the credit cards required by ride-sharing apps. They could commission vans that could pool more people than a car, providing a nice midpoint between personal vehicle ownership and a bus.

If cities leave self-driving cars entirely to the private sector, they court risk. When the usage of public transit grows or shrinks, the city knows immediately, and can adapt to what the public is demanding. But companies like Lyft and Uber are opaque, releasing very little information about their usage. This is already making it hard for San Francisco to plan for the future: Figuring out where to develop public transit hinges on understanding how people are moving themselves around using private-sector means. “We don’t have the data to understand the market size and what’s happening to it,” says Timothy Papandreou, the city’s director of strategic planning and policy for SFMTA.

As Radulovich points out, there’s historical precedent for the government getting more deeply involved in regulating private ride-sharing. After all, today’s public transit started out as a hodgepodge of private systems—a bus line here, a streetcar there—that slowly merged into one large system. “Public transit went through this—it was venture funded, but then it became public.” That reverse privatization is unlikely to happen again, but cities could ensure the system serves civic needs by using carrots and sticks: incentivize people to use ride-sharing but require that ride-sharing firms share their data.

Gabe Klein argues that good deals can serve both the city and the private sector. When he ran the transportation system in Washington, DC, Klein—who’d previously worked for Zipcar—created a new policy: Zipcar would be allowed to park its cars for free in some curbside city spots. It was controversial: giving away a public resource to a private firm? But Klein argued that because a single Zipcar is used by many people and driven far more often than a regular single-owner car, each would take cars off the road. Klein also got DC to charge more for on-street parking, again nudging people away from owning private cars. In the ensuing years (which also saw the rise of the ride-sharing apps), DC saw 6 percent fewer registrations for cars, even as the population increased by 3 percent.

Obviously, cities should get cracking on their plans for the self-driving future. But are there things they can do right now to reduce the amount of parking and driving?

Shoup recommends that cities apply something like Uber’s infamous surge pricing to parking: If a block tends to be full of parked cars at a particular time of day, the city should charge more, and if the demand is lower, it should charge less. The goal, Shoup says, is to price parking so that there are always one or two spots open on a block. Achieve that, and presto: A city could get rid of circling, since drivers could always quickly find a spot. Emissions and traffic would go down, while higher meter fees would encourage use of public transit.

Shoup recommends that cities apply something like Uber’s infamous surge pricing to parking.

Would dynamic pricing actually work?

In 2011, San Francisco decided to find out. In several areas of downtown, it set up new high-tech meters and sensors in the ground that told the city how busy these blocks and city parking lots were from morning to noon, from noon to 3 p.m., and from 3 p.m. to the evening. Every few months, the city examined the data and adjusted the price for each time segment of each block or lot up or down. Over the next two years, the city shifted parking costs upward on 37 percent of the time segments per blocks or lots, while at another 37 percent, the prices dropped. (The price of the others fluctuated.) It turned out that the hottest demand for parking was between noon and 3 p.m.

The new pricing scheme had precisely the effect the city hoped it would. Blocks that were previously jammed all day now typically had one spot open. Overall, driving in the pilot areas went down by about 2,400 miles per day—and circling plummeted by 50 percent. That helped reduce greenhouse gas emissions by 30 percent. (In comparison, areas in the city that weren’t in this pilot study saw their emissions go down by only 6 percent.) Meanwhile, drivers reported that it took them 43 percent less time to find parking. And the program was even profitable: The city took in $3.3 million more at the meters, even as it lost $500,000 as parking citations decreased.

“Seeing the circling go down was one of the nicest findings,” said Tom Maguire, director of Sustainable Streets for the city’s Municipal Transportation Agency, when I visited him in his downtown office. “The circling hurts everybody: air quality, greenhouse gas, collisions, making the streets much less pleasant.” He was also happy to put some meat on Shoup’s arguments against free parking. “If there’s one takeaway, it’s that the theory is true: If you raise the price, you have a little less parking demand. Until we did something on the scale of almost the entire downtown of San Francisco plus seven other neighborhoods, I don’t think it had been proven that the theory was true.”

So far, alas, few cities are following San Francisco’s lead. People—especially merchants—tend to holler when a city starts charging for parking. Three years ago, Ellicott City, a historic town in Maryland, installed smart meters on its main drag, only to have so many merchants complain that the city soon tore them out.

Shoup thinks cities need to be politically savvy to get citizens on board. One way, he says, is to engineer the meters to provide a hyperlocal benefit—plow some of the profits a meter generates back into sprucing up the very street on which the meter sits. Ventura County in California installed smart meters that were connected by wifi to the city, and then used those meters to broadcast free wifi to locals. It was an immediate hit.

But the central policy that can discourage the growth of parking is to eliminate minimum parking requirements. Take Los Angeles, which used to force developers to build two parking spots for every new unit of housing, hampering redevelopment in the downtown core. In 1999, the city eased the rules, and in a short time, developers started renovating the old buildings, providing an average of only 1.3 parking spots per unit. Buyers didn’t care: They still bought the housing. The market, as Shoup observes, is willing to cope. Build less parking, and people will find other ways to get around.

A lower-parking future could be downright lovely, judging by a glimpse I recently got of it. I was walking through the Mission District of San Francisco when I came across a curious sight: two curbside parking spots that had been transformed into a tiny public “parklet.” Built out of huge, curved pieces of wood, it looked like a ship beached on the side of the road. Two young men sat on the benches having a business meeting. Across the street was another parklet, where thick desert vegetation—some clipped to resemble a triceratops—spilled out in front of a private residence.

Founded five years ago—and since emulated by cities ranging from London to Ames, Iowa—San Francisco’s parklet program allows a property owner or business to apply to transform their storefront parking spots into a wee little plaza. There are now scores of parklets throughout San Francisco, including a particularly fascinating cluster of nine between 20th and 24th streets on Valencia Street. As I toured the strip, it gave me a vision of how remarkably a city could evolve: Imagine if 90 percent of all curbside parking spots were turned into strips of public parks, filled with greenery, urban gardening, and people relaxing.

They are oddly peaceful places. A few blocks down the strip at another parklet with a rainwater catchment exhibit, I found Nicole Hubman, a 30-year-old who was sitting and reading, waiting for her yoga class across the street. It turns out that Hubman’s life is a study in the massive changes already underway in our relationship to driving. She used to live in Boston, where her commute was an hour and a half each day. She hit her own Marchetti Wall, and it made her miserable. So when she moved to San Francisco, she decided to get around on public transit.

“I hate driving,” she says. “I’m allergic to it.”

This story was originally published by Mother Jones and is reproduced here as part of our Climate Desk collaboration.