Andrew Hardy was crossing the street on an electric scooter in downtown Los Angeles when a car struck him at 50 miles per hour and flung him 15 feet in the air before he smacked his head on the pavement and fell unconscious.

The 26-year-old snapped two bones in each leg, broke a thighbone, shattered a kneecap, punctured a lung and fractured three vertebrae in his neck, in addition to sustaining a head injury.

“My brother thought I was dead,” said Hardy, who wasn’t wearing a helmet.

Doctors told Hardy he’d likely be paralyzed for life. Five months later, he has learned to walk again. But he says he’ll never ride another scooter.

“These scooters should not be available to the public,” Hardy said. “Those things are like a death wish.”

As stand-up electric scooters have rolled into more than 100 cities worldwide, many of the people riding them are ending up in the emergency room with serious injuries. Others have been killed. There are no comprehensive statistics available but a rough count by The Associated Press of media reports turned up at least 11 electric scooter rider deaths in the U.S. since the beginning of 2018. Nine were on rented scooters and two on ones the victims owned.

With summer fast approaching, the numbers will undoubtedly grow as more riders take to the streets. Despite the risks, demand for the two-wheeled scooters continues to soar, popularized by companies like Lime and Bird. In the U.S. alone, riders took 38.5 million trips on rentable scooters in 2018, according to the National Association of City Transportation Officials.

Riders adore the free-flying feel of the scooters that have a base the size of a skateboard and can rev up to 15 miles per hour. They’re also cheap and convenient, costing about $1 to unlock with a smartphone app and about 15 cents per minute to ride. And in many cities, they can be dropped off just about anywhere after a rider reaches their destination.

But pedestrians and motorists scorn the scooters as a nuisance at best and a danger at worst.

Cities, meanwhile, can hardly keep up. In many cases, scooter-sharing companies dropped them onto sidewalks overnight without warning.

Regulations vary from place to place. In New York and the U.K., electric scooters are illegal on public roads and sidewalks, even though riders routinely flout the law. Last week in the Swedish city of Helsingborg, a rider was struck and killed by a car just one day after scooters were introduced there, leading to immediate calls for a ban. And in Nashville, Tennessee, where another rider was killed, the city’s mayor warned scooter operators they had 30 days to clean up their act or he would propose a ban.

Fed up with the thousands of scooters flooding Paris streets, Mayor Anne Hidalgo announced new regulations Thursday limiting the number of scooter operators and imposing a 5 mile-per-hour speed limit in areas with heavy foot traffic. The city has already imposed a 135 euro ($150) fine on anyone who rides scooters on sidewalks.

Isabelle Albertin, a pianist at Paris’ famed Opera Garnier, suffered a double fracture of her right arm after she was run down by an electric scooter on May 17. She is suing the city and has started an organization to push for a ban.

“On the sidewalks of Paris, it’s a total madhouse. We pedestrians are totally insecure,” she told Le Parisien newspaper.

Data on injuries or fatalities linked to scooters is hard to come by because the industry is so new. In Austin, Texas, public health officials working with the Centers for Disease Control counted 192 scooter-related injuries in three months in 2018. Nearly half were head injuries, including 15% that were traumatic brain injuries like concussions and bleeding of the brain. Less than 1% of the injured riders wore a helmet.

Bird, one of the largest scooter-sharing companies, dropped its scooters on the streets of Santa Monica, California, in September 2017 and within a few months riders were showing up at the emergency room, according to Dr. Tarak Trivedi, an emergency room physician in Los Angeles and co-author of one of the first peer-reviewed studies of scooter injuries. The following year, Trivedi and his colleagues counted 249 scooter injuries, and more than 40% were head injuries. Just 4% were wearing a helmet.

“I don’t think our roads are ready for this,” Trivedi said.

Bird and Lime both recommend that riders wear helmets, and they’ve handed out tens of thousands for free. But last year, Bird successfully fought a California proposal that would have required helmets for adults, maintaining that scooters should follow the same laws as electric bikes that don’t require adult helmets.

Bird says helmet requirements are off-putting to riders and could lead to fewer scooters on the road. Almost counterintuitively, the company argues that it’s better to have more riders than less because it forces drivers to pay attention to them.

“There’s a safety in numbers effect, where the motorists know that there’s people out on the street, so they act accordingly,” said Paul Steely White, director of safety policy and advocacy for Bird.

Getting people to wear helmets is a challenge. Riders don’t want exposure to lice or germs that could be found in shared helmets, and many make a spontaneous decision to scoot while they’re already out and about.

That was the case when Drew Howerton, 19, hopped on a Lime scooter on a whim last October in Austin. He recalls signing a waiver that said he should wear a helmet, but he didn’t have one on him.

“I didn’t show up in Austin thinking I’m going to ride a scooter today, better bring my helmet,” Howerton said.

Scooter-sharing companies generally restrict riding to those 18 years and up, but some children, or their parents, have found ways around that. A 5-year-old boy died in Oklahoma after he fell from a scooter he was riding on with his mother and was struck by a car.

Bird and Lime are taking steps to try to make scooters safer. After observing that scooter-related fatalities often occur after midnight when riders may have been drinking, Bird ceased operations after midnight. Lime halts rentals overnight in some markets but in most its scooters are available all night.

Lime has also been updating the design of its scooters, with a broader wheel base and better suspension and braking; Bird is including more durable brakes and reinforced hardware to prevent failures.

Both companies have been pushing cities for more bike lanes and better infrastructure as their riders navigate roads and traffic under conditions that were designed for cars and trucks.

“The reality is, cars continue to kill more people annually than any other mode of transportation,” Lime said in a statement. “We must address this issue together with cities, get people out of their vehicles, and build cities that put people first, with smarter infrastructure to protect riders.”

For Howerton, his first experience with a scooter left him scarred. Even though he read the warning not to ride downhill, he did it anyway since hills are hard to avoid in Austin. When he tried to brake, he flew off the scooter and hit his head on the pavement, blood gushing into his eyes.

“These companies, for the large part, they show up in cities and they just kind of dump these rideshare devices,” Howerton said. “They tout them as this really cool, innovative, public transportation thing that’s cheap and affordable and yeah it is, but they’re dangerous and they don’t think about the potential health consequences.”