People are getting injured while riding electric scooters. This shouldn’t come as a huge shock to anyone who has noticed the explosion of dockless, shareable two-wheelers over the last year and a half. But the degree to which people are breaking bones and sustaining head injuries is alarming public health officials who released a major study into scooter-related injuries on Thursday.

The study, which was conducted by the Public Health and Transportation departments in Austin, Texas, in association with the Centers for Disease Control and Prevention (CDC), identified a total of 271 people with potential scooter-related injuries from September 5th through November 30th, 2018. The study was presented by the CDC at its Epidemic Intelligence Service conference in Atlanta.

During the study period, there were a total of 182,333 hours of e-scooter use, 891,121 miles ridden on e-scooters, and 936,110 e-scooter trips. The research team calculated that there were 20 individuals injured per 100,000 e-scooter trips taken during the three-month period.

Of those injured riders, almost half sustained head injuries. Fifteen percent experienced traumatic brain injuries. These injuries could have been prevented by wearing a helmet, but only one of 190 injured scooter riders was wearing one. 

“These injuries may have been preventable,” the study concludes. “Studies have shown that bicycle riders reduce the risk of head and brain injuries by wearing a helmet. Helmet use might also reduce the risk of head and brain injuries in the event of an e-scooter crash.”

Dockless electric scooters and bikes have become a phenomenon in numerous cities and college towns as venture capitalists have poured money into a host of startups like Bird and Lime. The scooter boom has even attracted ride-hail giants like Uber and Lyft, which are looking to offset their contribution to rising traffic congestion by replacing short car rides with bike and scooter trips. They’re wildly popular, too: 38.5 million trips were taken on shared scooters across dozens of US cities in 2018, according to the National Association of City Transportation Officials.

Along with the proliferation of dockless scooters are a host of safety problems and complaints about regulatory oversight. Scooter companies have largely adopted Uber’s model of asking forgiveness rather than permission from city officials, raising the ire of regulators. Injuries have become a big problem, too, with many scooter companies struggling to promote safety without compromising the inherent convenience of hopping on a scooter at whim.

There have been other studies investigating the rise in scooter-related injuries, but the Austin study was the first to be overseen by federal epidemiologists. Austin Public Health worked with three CDC researchers to interview people who were injured by or while riding an e-scooter to learn about environmental factors and clinical information.

Almost half of the injured riders reported sustaining a “severe injury,” the study says. The study authors define severe injuries as bone fractures (84 percent); nerve, tendon, or ligament injuries (45 percent); severe bleeding (5 percent); and sustained organ damage (1 percent). No one died during the study period, but there have been a handful of reported deaths across the country.

The research team also took note of where people were being injured. Over half (55 percent) were injured in the street, while a third (33 percent) were hurt on the sidewalk. Cars or other motorized vehicles factored into 16 percent of injuries, but only 10 percent of riders actually collided with a car. Ten percent of injured riders hit a curb, and 7 percent struck an inanimate object, such as a light pole or manhole cover. 

A third of respondents acknowledged that they drank alcohol in the 12 hours preceding their injuries. More than one-third (37 percent) blamed their injuries on going too fast on the scooter. An alarming nineteen percent blamed the scooter itself, suspecting its brakes or wheels had malfunctioned. For several other injuries, distracted driving may have been at play: one person was talking on the phone when they crashed, and six had music or podcasts playing.

There’s a perception that most scooter injuries occur at night, but the study shows that less than half (39 percent) took place in the hours between 6PM and 6AM. An additional 20 percent took place during morning and evening rush hours, and 22 percent took place during work hours.

Unsurprisingly, a third of the interviewed riders were injured during their first e-scooter ride — a key finding of the report, the authors say. Most of the scooter companies require riders to swipe through a safety tutorial before they’re allowed to start riding, but it may not be properly preparing people for the experience of whipping through town at speeds of up to 20 mph while in a standing position. Seventy percent of interviewed riders said they’d received scooter training before being injured, and 60 percent said that training came from the scooter company’s app.

“Our findings show the risks involved in riding scooters and have significant implications in considering what individual safety measures can help reduce injury,” Stephanie Hayden, director of Austin Public Health, said in a statement.