People are getting injured riding electric scooters — and most riders aren’t wearing helmets, new research says. The findings highlight the safety risks when infrastructure and regulation fail to keep up with a controversial and popular new transportation trend.

Over the course of a year, at least 249 people visited two Southern California emergency rooms with broken bones, bumps, bruises, and head injuries — including brain bleeds — from scooter accidents, according to a paper published today in the journal JAMA Network Open. While most of the injuries were from riding the scooters, some pedestrians were injured when scooter riders crashed into them, and others tripped over scooters while walking.

It’s the first comprehensive study to report the range of injuries resulting from the new scooter-sharing craze, and it could help scooter companies and cities figure out ways to prevent them. But actually implementing safety fixes could take a long time — just look at how communities have handled the introduction of bike lanes, or even sidewalks.  

The rise of motorized scooters kicked off in 2017 when hundreds of two-wheeled vehicles started appearing on city streets in California. People responded by tossing the scooters into bodies of water, outfitting them with seats, and, of course, riding them. These motorized scooters can reach speeds of 15 miles per hour — and faster speeds mean more chances for dangerous injuries, says Frederick Rivara, a professor of pediatrics at the University of Washington who was not involved in the study. “This is what I expected to see, and it’s concerning,” says Rivara, who wrote an editorial about the study that was also published today. “The problem is only going to get bigger.”

The research started when Tarak Trivedi, an ER doctor at UCLA and a research fellow at the National Clinician Scholars Program, started seeing the scooters popping up in Santa Monica. “They’re appearing everywhere, they’re controversial, people are shaking their fists at scooter riders as they ride by,” he says. Trivedi isn’t one of the fist-shakers — he actually rides scooters himself, always with a helmet. But, he adds, “it wasn’t long before I started seeing patients in the emergency department where I work at UCLA who had scooter-associated injuries.”

Trivedi wanted to find out if there were any common trends to the injuries or the people coming in with them. That way, policymakers and scooter companies might be able to come up with strategies to prevent them. So he and his colleagues dug through a year’s worth of emergency room records at Ronald Reagan UCLA Medical Center and UCLA Medical Center, Santa Monica.

They found 523 medical record entries containing the words “scooter,” “lime,” or “bird” starting in September 2017. (Lime and Bird are scooter startups.) Of those, 79 were thrown out because because “bird” or “lime” meant something else, “such as a name of a person or street or the animal or fruit,” the study says. Others were tossed because it was the wrong kind of scooter. In total, 249 records were explicitly about electric scooter injuries.

The study doesn’t look at the rate of scooter injuries compared to say, rates of injuries from car accidents or bike crashes. They do report finding records for 195 bike accidents and 181 pedestrian injuries at those same hospitals. “We don’t know anything about miles ridden, or the number of rides taken, or the number of people who ride scooters on a daily basis,” Trivedi says. “At this point, it’s not clear whether or not riding them is more dangerous than riding bicycles.”

That’s not what the study was investigating. Instead, the team looked at patterns in the scooter injuries, and they found that most of the patients were riding the scooter when they got hurt. (And 27 of the riders, or about 11 percent, were under age 18 — which goes against the scooter companies’ regulations, the study says.) The majority were injured by falling, but about 11 percent hit something, and another 8.8 percent were hit by a car or some other moving object. And people didn’t have to be riding the scooters to be injured by them, the team discovered: another 21 people were either hit by a scooter, fell over a parked scooter, or hurt themselves trying to lift one.

About 40 percent of patients suffered head injuries, and several of those were especially serious — including five brain bleeds and a concussion. But the trouble with the hospital records was that they didn’t go into much detail about the nature of the rides themselves. About 12 noted the patients had been drinking, for example. And the records for only 10 patients, or 4.4 percent, explicitly said the patient had been wearing a helmet, for example.

So to get a better sense for how people were using scooters, Trivedi and his team parked themselves on street corners to watch 193 people scooting by. “We saw all kinds of things,” Trivedi says: there were tandem riders, parent-child pairs, people riding on sidewalks and ignoring traffic laws. And 94 percent weren’t wearing helmets. Although the scooter company Bird supported California legislation to make helmet use optional for adult riders, according to CNET, that didn’t go into effect until January 1st of this year. At the time, those bare-headed riders were flouting local law.

That’s why Rivara thinks scooter companies should start figuring out ways to give people easy access to helmets. But he adds that while bike helmets certainly reduce the risk of injury, they may not be enough at higher speeds: “Since these things are motorized, we don’t really know whether bicycle helmets will be adequate or not,” he says. He’s hoping that the federal Consumer Product Safety Commission gets involved with testing bike helmets at scooter speeds. “I realize that there’s not an easy solution — if there was, we would have done it — but nevertheless that doesn’t mean you should ignore it,” he says.

Trivedi speculates that poor scooter maintenance could contribute to injuries. Although the study didn’t look into it, he’s heard patients complain of equipment failures, like problems with the brakes. He recommends riders test their scooters’ brakes before hopping on, and that companies make it easier to report damaged scooters.

Paul Steely White, director of safety policy and advocacy for scooter startup Bird, says in an emailed statement that they hope to work with the study authors going forward. “Bird did not have the opportunity to work with the study’s authors or to collaborate with them, and we find the report to be very limited,” he says. He, like Trivedi, points out that the study doesn’t look at the rate of accidents compared to motorcycle or car accidents. “The number of injuries reported would amount to a fraction of one percent of the total number of e-scooter rides.” (Since scooter rides tend to be short, however, injuries per mile might be a better comparison.)

In an emailed statement, Mary Caroline Pruitt, a spokesperson for Lime, says safety is the company’s first priority. She listed company safety initiatives, including “250,000 free helmets distributed to riders across the globe,” she says. “We’re also working with local governments around the world to support infrastructure for shared scooters and bikes.”

After all, the responsibility for rider safety doesn’t rest solely with the companies; Trivedi also wishes cities would make roads safer for both cyclists and scooter riders by keeping roads maintained and setting aside space in traffic for non-car vehicles like bicycles and scooters. “Scooters go 15 miles per hour, so it’s a recipe for disaster if you don’t dedicate a space on the road,” he says.

For Trivedi, the findings haven’t dissuaded him from riding electric scooters. But he’s going to keep wearing his helmet, no matter how annoying it may be to lug it around restaurants and movie theaters. “If anything, I’d say I’m pro-scooter,” he says. Aside, of course, from the injuries. “We just have to use them really safely.”