I’m on a tree-lined street in Lincoln Park, a city in Metro Detroit, studying a curb ramp—the part of the sidewalk that slopes down to meet the street at an intersection so that someone using a wheelchair can safely cross. I mark the ramp “good” and move on.
Psych! I’m not in Lincoln Park. I’m labeling and rating sidewalks from the comfort of my own couch in Los Angeles using Project Sidewalk, an online crowdsourcing platform dedicated to improving sidewalk accessibility.
Part immersive video game, part educational tool, Project Sidewalk allows people around the world to navigate down virtual streets using Google Maps Street View imagery, cataloging broken sidewalks, missing curb ramps, and faded crosswalks. That crowdsourced data, in turn, can feed powerful AI tools to detect and catalog sidewalk issues automatically.
Founded in 2012, Project Sidewalk was created to solve a fundamental problem: Cities don’t know the condition of their sidewalks. This spells disaster for pedestrians, especially people with disabilities.
The goal was initially to map every sidewalk, everywhere, all at once—but that’s shifted over the years.
“AI has never been better,” says Jon Froehlich, Project Sidewalk cofounder and professor of computer science at the University of Washington. “It’s certainly not good enough as an expert evaluator, and it most certainly can’t capture the perspective of lived experience.”
Instead, Project Sidewalk has become a powerful tool for community engagement and grassroots political action on the local level.
Starting in 2021, Girl Scouts and community members in Oradell, New Jersey, mapped nearly 36 miles and identified more than 11,000 potential sidewalk issues. The Scouts then presented their findings to the city council, advocating for adding missing curb ramps to improve accessibility.
Mapping sidewalks is hard but machine learning has shown great promise on one front: finding curb ramps. A recent mapping attempt found that a new ramp detection tool was more accurate than humans at 96.9% in Vancouver, Washington.
However, AI is not as good at finding things that are caused by nature, like sidewalk uplifts from tree roots, says Froehlich.
Many sidewalks in the U.S. are either missing or broken—but so is available sidewalk data. Part of this is due to a fear of liability, experts say.
If someone trips and falls due to a crack in the sidewalk and can prove that the city knew about the issue, could that mean an expensive payout in the case of a lawsuit? “If only we had a nickel,” jokes Froehlich about the number of times he’s heard this.
To combat this fear, the Great Lakes ADA Center published a story map about ADA lawsuits. Part of the problem, says Yochai Eisenberg, site lead for Project Sidewalk at the University of Illinois Chicago and co-author of the report, is the lack of clear guidance from the federal government. Despite this, he believes data is an asset, not a liability.
“Having data, having a plan, making progress towards that plan is just the clearest way to defend against any lawsuit,” he says.
In fact, cities are required to develop and maintain an up-to-date ADA transition plan showing how they will make streets and sidewalks accessible to people with disabilities. Unfortunately, very few cities have a compliant transition plan.
Instead of being driven by data, sidewalk improvements are often driven by complaints. But with a dual approach of crowdsourced data and community engagement, some cities have won infrastructure dollars to improve accessibility.
In Mendota, Illinois, community members, including middle and high school students, mapped streets and won $3 million in grant funding.
“They’re an older city, they had a lot of missing sidewalks, a lot of missing curb ramps,” Eisenberg says. “So it was clear why they could make a clear case about why the funding was needed for receiving that grant.”
Sidewalk data alone isn’t enough to fix broken sidewalks, but without it, it’s impossible to do so equitably, believes Laura Messier, a researcher studying the relationship between public health and the public-right-of-way. (Froehlich is a member of her dissertation committee.)
“The inventorying of the sidewalks could very much show people, ‘Yes, we are moving toward improving these conditions,’” she says. “But again, only if combined with actual money and actual action.”
Compared to roads, sidewalks have historically been underfunded and treated as secondary transportation infrastructure. Many people are surprised to learn that sidewalk maintenance is often the responsibility of the adjacent property owner, further fragmenting governance of the public-right-of-way.
“Someone is also going to have to coordinate them and basically force them to do that work, because they’re not going to do it on their own,” Messier says. “It just seems, on its face, insane.”
In Denver, voters passed a 2022 ballot measure for a special fee to fund sidewalks. “For the first time, sidewalks will function more like streets, with ongoing citywide care, consistent standards, and dedicated funding,” reads the sidewalk program’s website.
To Messier, the path to better sidewalks lies in cities taking ownership of sidewalks as public space. This shift, from property owner discretion to public asset is long overdue—but not everyone wants sidewalks.
“In my own experience in Dallas, I definitely talked to people who did not want sidewalks in front of their house, because there was this perception of, ‘You’re inviting the public in,’” Messier says.
In Seattle, Froehlich was surprised to find that one of the wealthiest neighborhoods has very poor infrastructure.
“They have sidewalks on both sides of the street, but not a lot of curb ramps,” he says. “I don’t know if that’s a measure of closing off that peninsula because they already feel a little insular.”
The future of better sidewalks might be the next generation. An eighth grade student in Waltham, Massachusetts, told his teacher about Project Sidewalk and the entire class is now mapping sidewalks as a civics project. So far students have mapped nearly 18 miles or about 12% of the city’s sidewalks.
KiAnna Mckee-Steen, project coordinator for the University of Illinois Chicago, is developing K-12 curriculum for Project Sidewalk and has witnessed firsthand how it’s changed how students view the world.
“This wasn’t an issue that I was aware of growing up,” Mckee-Steen says. “I had streets that had sidewalks, I had streets that didn’t have sidewalks, but we just walked in the street. I didn’t realize how much people were impacted that couldn’t move like me.”
This story was originally published by Next City, a nonprofit news outlet covering solutions for equitable cities. Sign up for Next City’s newsletter for its latest articles and events.