As a driverless future dawns, should we still build parking?

No one is really sure how many parking spots the United States contains, but estimates stretch up to 2 billion.

This may conjure up images of asphalt seas surrounding suburban shopping malls, but city centers have their fair share as well. Manhattan, arguably one of the least amenable places in the country to cars, has 102,000 public off-street parking spaces below 60th Street — more than four times the size of Disneyland. Studies have shown that a significant number of the cars circulating in central business districts at any given time are just looking for parking.

It also plays a major role in new construction, and not for the better. “Parking is the 800-pound gorilla in land development,” said Will Baumgardner, leader of Arup’s transport and mobility business in the Americas. On most projects, municipal zoning codes require developers to provide at least a set minimum amount of parking. Investors also exert pressure on this front. They often hesitate to fund projects with fewer-than-normal spots, fearing that potential tenants will be scared off by concerns over inaccessibility.

As a result, Baumgardner said, “many office projects build as much space for parking as floor space for people” — significantly increasing the development’s overall cost.

New frontiers

As autonomous vehicle (AV) technology advances, forward-thinking designers, developers, and policymakers are beginning to envision a world with much less parking.

Imagine a future in which shared AVs zip constantly from one place to another to pick people up and drop them off, rarely sitting idle. During periods of lower demand, they park in garages outside city centers.

One study suggested that every self-driving vehicle could remove 10 other cars from the roadAnother projected that the use of shared AVs could lower the demand for parking by 90%.

Few would mourn parking’s loss. Developers would love to be able to do away with it — garages can cost well over $25,000 a space. Cities could use the land to build more of everything else instead: housing, parks, schools. As for drivers, when was the last time you wished you could spend more time looking for parking?

Uncertain timeframes

But parking won’t disappear overnight. Before it can be phased out, we’ll need to see massive shifts in consumer behavior, as well as large-scale retrofitting of urban infrastructure.

The latter may be more straightforward than the former. Kara Kockelman, an engineering professor at the University of Texas at Austin and a leading expert on AVs, said that tailoring the road network to accommodate the new technology would be relatively simple from a design perspective. “You could have shared drop-offs, much like bus stops; geofencing rules allowing for self-driving cars in certain areas; and areas where empty self-driving cars could park themselves. It wouldn’t be that hard for a city to do.”

Credit: Arup

Consumer behavior is a bigger question mark. “We don’t know if consumers will use a fully shared vehicle network, or if they’ll purchase privately owned self-driving cars, or share privately owned ones with other households,” Susan Shaheen, the director of innovative mobility research at UC Berkeley’s Transportation Sustainability Research Center, wrote me in an email.

This uncertainty greatly complicates cities’ efforts to plan ahead. “Each of these scenarios has potentially very different implications on parking and infrastructure planning. We know there will be changes to urban design and urban form because of self-driving vehicles, but we still don’t know what those changes will be. It depends on how people use them.”

And how people use them will depend, at least in part, on where those people live, Shaheen said. Regional variables — policy, for instance — could make a big difference in how new technologies play out from city to city. As a result, no one-size-fits-all urban design solution is likely to emerge.

According to Baumgardner, the hazy timelines of AV adoption are also a major hurdle. “A lot of people speculate we’re in for a rapid, nearly instantaneous changeover,” he said, with driverless cars dominating the streets from the moment they hit the consumer market. He isn’t convinced that manned vehicles will become obsolete so quickly. “I think we still have many years to go.”

Proactive steps

Despite these unknowns, we can take steps today to prepare for parking-free cities in the future.

Finding creative ways to minimize the construction of new parking is an obvious place to start. “If we won’t need it in the long run anyway, let’s build as little as possible today,” Baumgardner said.

Although designers and developers in most cities must comply with government- and financer-driven parking minimums, they do have some room to maneuver. (Helpfully, some cities have started to establish parking maximums, or upper limits on the amount of parking that new projects can provide.) A number of strategies for maximizing the effectiveness of each parking space have been developed; designers can think through the pros and cons of each for specific projects.

 

Credit: Arup

Let’s say a developer is building a complex that contains offices and restaurants. Rather than adding up the minimum parking requirements for both and building that number, the design team can forecast that the office spots will sit empty at night and the restaurant spots will sit empty during the day. It can thereby reduce the total number of spots while providing adequate parking during peak usage times.

Designing for evolution is another important consideration. As demand for parking shrinks over time, existing spaces will be converted to other uses. Design teams can build this into their projects, creating parking lots that can morph into parks or other amenities in the future.

Perhaps most importantly, designers and developers can — and should — put people above cars. Private cars may disappear over the course of a development’s life span, but people won’t. Prioritizing human needs will go a long way toward future-proofing today’s projects.

 

Questions or comments for Will Baumgardner or Peter Moskowitz? Contact william.baumgardner@arup.com or peter.moskowitz@gmail.com.

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