How Autonomous Vehicles Could Help Transform Parking Lots
Researchers say it’s likely that autonomous vehicles (AVs) can help reduce the need for parking lots, opening more room for grass and trees and other elements of nature.
It may not seem like it when you’re circling the block looking for a parking spot, but there are more than three parking spots for every car in America, according to a research paper from the University of California, Berkeley. And that paper is more than a decade old. Some estimates now put that number up to eight spots per car.
“Parking is an enormous limiter of development,” said Nico Larco, a Professor of Architecture and Urban Design at the University of Oregon, where he is the director of the Urbanism Next Center and Co-Director of the Sustainable Cities Institute. Parking gobbles up land that could be used for retail development or housing. And aesthetically?
“Parking is not a beautiful thing,” Larco said.
Changing the picture
Several research models suggest that adoption of shared-used AVs could mean a 90 percent drop in parking demand. Shared-use AVs are part of the economy where transportation is seen as a service, like with ride-shares and cabs.
“The AV drops me off at work,” Larco said. “And I don’t need to have the parking lot right next to me.”
“Parking is not a beautiful thing.”
The AV can then go pick up other riders — similar to the ride-share systems we use today — or self-park outside the city center where parking fees are cheaper.
One parking deck could serve an entire business district. One study suggests that almost 11 parking spaces can be eliminated for every shared AV. When not in use, the cars would return to their depots, likely outside the cities, where they can be cleaned, serviced, and parked securely.
Dramatically reduced demand for parking offers opportunities for redevelopment. For example, various kinds of parking – curbside, private lots and garages, etc. – in New York City consume 480 million square feet. For a sense of scale, then think Central Park — times ten. Space and infrastructure dedicated to parking could be repurposed to make cities cooler, greener and more vibrant.
Hard surface parking lots contribute to water pollution because they collect trash, bacteria, heavy metals and other contaminants that get picked up by runoff when it rains. The rapid rush of rainwater can overcome sewage systems, making wastewater treatment less effective.
Those problems can be addressed by replacing parking lots with green infrastructure that slows the runoff, spreading it out over the land and slowly soaking it into the ground, said David Rouse, a planner, landscape architect and former research director for the American Planning Association (APA) in Washington, D.C. Green infrastructure includes rain gardens, planter boxes and bioswales.
“There are a lot of benefits that trees bring to an urban environment.”
Parking lots also contribute to the urban heat island effect. The heat island effect increases daytime temperatures in urban areas about 1–7°F higher than temperatures in outlying areas and nighttime temperatures about 2–5°F higher, according to the U.S. Environmental Protection Agency. Converting parking lots to parks and open spaces, Rouse said, would help mitigate climate change.
“There are a lot of benefits that trees bring to an urban environment,” he said, noting that trees sequester carbon, remove air pollutants and cool hot city streets.
An urban tree canopy reduces concentrations of particulate matter, the most harmful type of air pollution, according to a report by The Nature Conservancy published in the journal Environmental Pollution in 2014. A 2010 study found that trees removed 17.4 million tons of air pollution across the United States, which prevented 850 human deaths and 670,000 cases of acute respiratory symptoms.
Rouse said urban tree planting could even create “food forests,” where the trees that form the canopy produce fruit and nuts, and the understory features fruiting shrubs like huckleberry, elderberry and currant. There are even studies that suggest more trees means less crime.
Both Larco and Rouse noted that parking lots are low-value uses of real estate and that widespread use of AVs could trigger conversion of sterile parking lots into more lively elements of a city — restaurants, bars, apartments, condos and experiential spaces like galleries, museums, concert halls and more.
In some cities, there are more places for cars to spend the night than there are for the drivers. A 2018 study using satellite data and other sources to determine the number parking spaces in five cities: New York City; Philadelphia; Des Moines, Iowa; and Jackson, Wyo. Only in New York City are there more homes than parking spaces. Jackson has about 27 parking spaces per household.
As such, redevelopment of parking lots could mitigate the housing crunch that drives up the cost of living in many cities. Conversion of parking decks into apartments is more problematic, Larco said. The ceilings are typically too low and the ramps too steep to renovate into housing. But parking decks, Larco said, could be converted into vertical gardens where herbs and vegetables can be grown using hydroponics just blocks from restaurants and grocery stores.
Some developers are building parking decks with an eye to a future when AVs dominate the roads. The World Trade Center Denver Complex, a 600,000-square-foot multi-use urban center scheduled to open in 2024, has a deck with more than 700 parking spaces designed so that the spaces can be eventually renovated into residential, office or retail space.
Right now, so many American cities are built for cars. With the deployment of AVs, cities can start imagining redeveloping areas for humans.