DEEP DIVE: Are E-Scooters Unsafe At Any Speed?

Photo:  Elvert Barnes/Flickr/CC
Photo: Elvert Barnes/Flickr/CC

SB Donation NYC header 2In just over a year, e-scooters have gone from a freakishly rare novelty to almost ubiquitous in American cities.

Billions of venture capital goes a long way, fast. Bird alone claims to be operating in more than 100 cities.

There are as many as 17,000 e-scooters on the streets of Los Angeles, the Wall Street Journal reports, available to adults for as little as $1.15 per ride. And there are 13,000 in San Diego and almost as many in Austin.

We’re just now beginning to understand the impacts.

The CDC is gearing up to do the first authoritative study of e-scooter safety. The study will examine 68 e-scooter injuries that took place over a two-month period in Austin. Over that time, there were 37 EMS calls or about one every other day, the report says. There are almost 12,000 e-scooters approved for operation on Austin’s streets and they took about 235,000 trips in October, according to city data.

Meanwhile, in recent months there has a been rising alarm about injuries. Doctors in cities such as Nashville and St. Louis have discussed worrying levels of injuries, saying scooter crash victims are flooding their emergency rooms.

Apparently, mayors have concerned as well.

“Every mayor who’s got ’em comes up to me and says, ‘Don’t take ’em,” Seattle Mayor Jenny Durkan said  recently. “And the reason is … every city that has scooters has significant traumatic injuries.”

San Jose Mayor Sam Liccardo last week threatened to ban them unless the companies could use a technology like geofencing to keep e-scooters off the sidewalks.

“If there is not significant improvement in safety of e-scooters, ultimately bans are coming,” he told the San Jose Mercury News. “There are serious injuries happening out there.”

The scooter companies — especially Bird — have deflected such concerns by pointing to the far more catastrophic danger of cars. Their defenses mirror, to an uncanny degree, urbanist messages. In response to a class-action suit by injured scooter users, Bird said:

“Class action attorneys with a real interest in improving transportation safety should be focused on reducing the 40,000 deaths caused by cars every year in the U.S.”

So how are e-scooters performing on safety? It’s not an easy question to answer, in part because the scooter companies have been pretty secretive with their data, although that’s beginning to change. And it’s also difficult to say because scooters are such a new technology and, as they become integrated into urban landscapes, may experience lower and lower injury rates as cities redesign streets — similar to how cities such as New York reduced cycling deaths even as the numbers of bike riders increased.


So far there have been two — or three — e-scooter deaths it depends on how you count them.

In D.C. in September, a 20-year-old man was killed when he was struck by an SUV driver while riding a Lime scooter. In Dallas the same month, a 24-year-old man died in what appears to have been a solo fall from a Lime scooter.

Finally, in August, a 21-year-old woman was killed in downtown Cleveland when she was struck by a driver who, cops say, high on heroin. She was riding a scooter-hybrid with a seat she had rented from a storefront rental business — not one of the mass marketed dockless varieties that have taken over cities.

It’s hard to assess two or three deaths out of 40- to 60-million rides on a completely new vehicle with which very few people have become comfortable. By comparison, cars kill about one person per 80 million vehicle miles, a number that has been declining over the long term. But given how many miles Americans drive, cars kill tens of thousands of people every year. Scooter trips are typically a mile.

To put those numbers in perspective, a 2015 study by Ralph Buehler and John Pucher estimated that 2.25 cyclists die on their own bikes, and 5 bike-share riders die, for every 100 million miles in London and Paris.

The London and Paris numbers “might be more comparable to the scooter data, since they are for cities rather than whole countries, and urban areas tend to be somewhat safer than rural areas,” said Kay Tscheke, a public health researcher at the University of British Columbia.

Based on Bird’s estimate of 40-60 million trips at roughly one mile, Tscheke said the range for e-scooters in the U.S. seemed to be between 2.25 and 5 deaths per 100 million miles.
“If these data are correct, the death rate seems to be within the range of death rates for similar modes of travel,” she wrote.

But so far, anyway, the record for e-scooters does seem to be a bit worse than bike share in the U.S. Last year, the National Association of City Transportation Officials wrote that there have been 123 million bike share trips through the end of 2017, going back almost a decade. The estimated length of those trips is between 1.5 and 3 miles.

There have only been two bike share deaths in the U.S. in the whole history of modern bike share. That means, using an average trip length of 1.5 miles, a conservative estimate, that’s a death rate of one per 92 million miles for U.S. bike share, even excluding all the miles ridden this year.


Evaluating injuries is more difficult. Anecdotal data are concerning, however, if you take them at face value.

Peter Holley at the Washington Post wrote in September that scooter riders were “pouring into emergency rooms” and that their injuries “looked like car wrecks,” including “broken noses, wrists and shoulders, facial lacerations and fractures, as well as the kind of blunt head trauma that can leave brains permanently damaged.” The story cited dangers in many cities.

In Santa Monica — the “e-scooter and e-bike capital of the world,” according to Curbed — 18 serious injuries were reported by the Fire Department over just a two-week period in July.

At St. Louis’s Washington University, professors recently sounded the alarm over the high number of injured scooter riders arriving in the affiliated hospital’s emergency room. They reported six to seven ER visits per week over a two-month period. It wasn’t just bumps and bruises. Of those injuries, six required surgery and 12 were admitted to that one hospital through the emergency room.

“The costs for our city to allowing these e-scooters has probably been underestimated,” the professors concluded.

Doctors in Nashville offered perhaps the most concerning anecdotal evidence yet about the safety of e-scooters. Vanderbilt Medical Center Trauma ICU director Oscar Guillamondegui told Nashville Public Radio that they were getting one injury per month that was “life changing,” meaning the person suffered what was likely permanent brain damage. For perspective, the city’s current policies allow up to 3,000 e-scooters in circulation.

The vehicles themselves

Image: Bird via PR Newswire
Image: Bird via PR Newswire

Some people question whether the design of the e-scooters used by Lime and Bird has inherent safety drawbacks.

“Scooters have small wheels,” Arizona State University Professor David King told Streetsblog. “That means they need really really flat smooth pavement. We don’t maintain that for anybody.”

The Riverfront Times, an alt-weekly in St. Louis, tested the devices in July, shortly after they arrived in the city. A mostly lighthearted article by Daniel Hill called them “moderately terrifying”:

Over the course of two days, I had to bail twice, went flying over the handlebars once (didn’t see that hole in the ground) and straight laid it down and slid across the pavement once (avoid multi-tasking with your hands while riding, even if you’re thirsty). Be prepared for road rash.

James McPherson, an attorney with experience litigating accident claims and who writes at, raised additional concerns about the design of e-scooters, including high center of gravity, a narrow side profile.

A seat might improve safety, making scooters more like low riding bikes without pedals than upright crash machines. A seated rider lowers the center of gravity and widens the profile so he or she is more visible from the side.

We asked a Bird spokesperson how the vehicles handle on potholes. On background, that person told Streetsblog it was riders’ responsibility to avoid potholes. That means riders have to be scanning the environment both for cars and the street for potholes at the same time.

We asked Bird other questions: Did the company make any attempt to design the vehicles for maximum safety? Did the company consider the bike infrastructure in a city before setting up shop? On the record, the company offered only boilerplate about how riders are encouraged to wear helmets and how Bird encourages cities to add bike infrastructure.

Cost, not safety, seems to be an important part of the business model.

According to the Wall Street Journal, e-scooters cost about $500 each. The profitability of the companies is directly related to the price per vehicle versus how many times it is rented before it needs to be replaced. Vandalism and wear and tear are forcing the companies to replace them every two months on average. And investment prospects have been softening in part because of the limited shelf-life of the vehicles, the Journal reported.

Both Lime and Bird are valued at more than $2 billion.

How big are the environmental benefits?

Both Lime and Bird are hoping cities focus on the potential environmental benefits of e-scooters over cars.

“We don’t have a year to wait,” David Estrada, Bird’s chief legal officer and head of public policy, recently told Curbed. “Are cities going to choose to help solve the climate crisis and get people out of cars?”

It’s impressive that e-scooters have amassed between 40 to 60 million trips for a form of transportation that barely existed a year ago. But how many of those are displaced driving trips?

We don’t really know. An often-cited, though unscientific, survey in Portland found the car trip replacement level was pretty high — more than a third for locals and even higher (51 percent!) for tourists.

The survey’s limited response rate makes it digestible only with more than a few grains of salt, but it wouldn’t be surprising if e-scooters were replacing car trips at close to that range. Of course, even with healthy car-replacement levels, a large number of trips will replace walking, biking or transit as well. In those cases, they may actually increase the environmental impacts of some short trips, especially since e-scooters have such a short shelf life.

Safer streets

Scooter companies say safety will improve as scooter use becomes more widespread, creating pressure on city officials to redesign streets and add bike lanes.

Anecdotally, it seems to be true. Kansas City recently tested out a combined bike and scooter lane. And Bird has begun providing money for cities to add bike infrastructure.

Perhaps, as Bird asserts, e-scooters will eventually displace enough car trips to have a measurable impact on traffic safety.

Researchers Peter and Joel Jacobsen — whose research helped establish the “safety in numbers” effect for biking — say they expect scooter injuries to decline as they become more common, as both drivers will become more aware of them and they help produce changes in the environment. The Jacobsens said, while there wasn’t very much data, they would expect the safety outcomes of e-scooters to be similar to biking and walking.

Our very rough fatalities analysis supports that idea. But if the injuries show something different, it will be interesting to see how that impacts the industry and the regulatory environment. It’s also possible it will help alleviate worries and lead to wider adoption.

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76 thoughts on DEEP DIVE: Are E-Scooters Unsafe At Any Speed?

  1. Maybe, but I still question the 15mph-0 responsiveness of his braking system.

    Honestly I probably did a mitzvah here, I was on a Citi Bike so I had some inertia. Probably prevented the guy from crashing into the taxicab.

  2. Well, that is the problem with socialized medicine. We get to pay for each other’s mistakes. Some cities have passed laws banning walking while talking on a cell phone. At some point one has to scratch one’s head and ask whether we really want to live in a nanny state. Of course, when as you say, we all end up paying for each other’s mistakes, we all have a vested interest in minimizing the mistakes. Hence a lot of laws (helmets, seat belts, etc).

  3. I have a friend who wiped out badly (ER visit and lots of road rash) and recently saw a couple using a scooter crash. Between the high center of gravity, the speed, and the little wheels, people are asking for it. I’ll be sticking with a bicycle or my own two feet.

  4. The scooters here in San Diego are supposed to be off the streets by 9:00 p.m. every night, so people shouldn’t be able to bar hop! Another flaw by the scooter companies.

  5. Scooters are definitely taking over for walking, and will increase the levels of obesity in the country.

  6. FWIW they use an insignificant amount of power to recharge. As in as if you were to walk instead and break enough of a sweat to need a shower, the energy used to heat the water for one shower could have taken you a hundred miles on a scooter.

  7. (Not reflected in its title but…) the video asks the question at the end: ‘Should e-scooters be on footpaths?’, i.e. what we call sidewalks here in Los Angeles.

    Bicycles should ALSO not be ridden on busy sidewalks in most cases, although in L. A. it’s not strictly illegal unless it’s being done in a reckless manner. In California, on the other hand any motorized device MUST be used in the roadway and never on the sidewalk…not that many of their riders are seen to be obeying this statute.

    As a veteran bicycle rider with over 50 years now on the streets, the e-scooters combine the worst of both worlds: 1. the added speed + high center of gravity are frightening in themselves; and 2. I might weigh 300 lbs. if I wasn’t on my bike every day. [Gave up my car 15 years ago.]

  8. Actually, my local police have told me e bikes can go wherever regular bikes can. And they are on the sidewalks and not for safety. For left turns. I have only seen two run ins with the e bikes, so far. Both times a regular cyclist got the wrong end of the deal. I live where there are a lot of bikes on sidewalks and it is extremely stressful to walk. I just passed one on the sidewalk. She was not there for safety. It was dark and she had no lights. She didn’t want to get cited. I guess she didn’t care the peds can’t see her coming either and naturally, I had to yield to her.

  9. Does it ever give you any pause that pedestrians have no voice in this? How is it you have no qualms about forcing this on us against our will? It is miserable to share sidewalks and crosswalks with motorized vehicles. Essentially, it eliminates them as pedestrian infrastructure. It negates their purpose.

  10. I bought an electric scooter ~15 years ago and fell on it after two days of light use, fracturing my elbow.
    The core reason these are unsafe at any speed (to their riders at least) is the too-small front wheel diameter. The new Lime S scooter has a bigger wheel, but they could go bigger still: 12-1/2″ wheels are a standard size and we should expect those in somebody’s fleet soon.
    Overall, this is a money grab fiasco, but it will encourage more bike and scooter infrastructure in cities as we get more shared vehicles. Smaller E-bikes make a lot of sense if docking (just lock them properly!) can be figured out.

  11. Scooters and bikes should be on the street.

    People are riding their scooters on the sidewalk in those places because they are afraid of cars moving more than twice the speed they are.

  12. The point of transportation is not environmental benefit. The point of transportation is to get people to their destinations. What you want is a transportation system that people are willing to use to get to their destinations, and that causes relatively low environmental impact.

    Scooters are definitely on the low end in terms of environmental impact. Not as low as walking or private bicycle, but it’s not obvious that they’re worse than transit.

    The real value of scooters though is that they are by far the fastest and most convenient mode of transportation for distances of .75-4 miles in a dense urban area. Biking is close in speed, but loses in convenience if it’s a private bike you have to park. Cars and transit are somewhat slower, particularly if transit requires a connection, and both are less convenient because you can’t just go door-to-door. (Cars can go door-to-door in lower density areas, but not if you need to use street parking in an urban area.)

    So if scooters can be the best transportation technology in terms of getting people to their destination quickly and conveniently, and can also have substantially lower impact than the currently most popular mode, then they seem like an improvement, whether or not they provide net environmental benefit compared to the current system.

  13. “User error” can’t entirely be blamed on the user. Some designs lend themselves to frequent user error. Other designs don’t. Just consider the number of “user errors” with things like television remote controls or laptop projectors, compared to the iPod. One of the many advantages of roundabouts over four-way stops is the way that roundabouts lead people to worry about their surroundings and avoid errors, while stop signs lead people to a false sense of security and have confusion about right-of-way.

  14. When I ask stand-up scooter riders why they’re on the sidewalk instead of the road, the usual reply is that they don’t feel safe riding on the road.

    Why don’t we have minimum requirements for motorized vehicles, such as, horsepower, torque, etc.? In SF, the motorized stand-up scooters are too weak to climb hills and have brakes that can’t stop them when going down hills.

  15. “you’re no faster than walking if you ride at” 8 mph?! Total BS!

    Average speed for all walkers (not just you and your friends) is 2.5 mph to 3.5 mph. 8 mph is more than 2 and 1/2 times faster than walking, ie 250% faster. This is a huge difference.

    The rest is BS too. “impossible to keep a bike at 8 mph” Please.

    “average cycling speed” 15 mph. Not. Try 10-12 mph. Once again, it’s not just you and people like you.

  16. You forget that if you ride at only 8 mph you get stuck waiting at a red light for 40 seconds every block. So it takes you 22.5 seconds to travel that one block (not counting accelerating up to speed), plus another 40 seconds waiting at the red light. That’s over a minute to go 1/20th of a mile, which is an average walking pace of 3 mph. 8 mph is only 250% faster than walking in your magical land where you never need to stop for anything.

    “average cycling speed” 15 mph. Not. Try 10-12 mph. Once again, it’s not just you and people like you.

    I’m talking about NYC, where people also tend to walk faster than average. Sure, I sometimes see people only going 10 or 12 mph, but they’re usually pensioners, or people with a really POS bike. There are lots of good reasons for cycling faster in a place like NYC. For one thing, the way the lights are often timed, you hit a lot fewer of them the faster you go. Therefore, the time savings are proportionately higher than the disparity if travel speeds would suggest. You might average only 3 to 4 mph if you cruise at 8 mph. If you cruise at 16 mph instead, which is twice 8 mph, you often average 12 to 14 mph, which is 3 to 3.5 times faster.

    What’s so great about riding slow anyway that a number of people here defend it? You take longer to get where you’re going, you don’t get any kind of work out, plus it’s boring as fuck to be plodding along like a tortoise. Every other mode of transport is considered better if we can make it go faster. Why not human-powered transport? I wish velomobiles would become mainstream so a person in average shape could cruise at 20 to 25 mph, while a strong rider could go 35 to 45 mph.

  17. Most Americans amble along at 2 to 3 mph because they’re FAT. It’s hard to move 300 to 400 pounds, which is the average weight of people in American suburbs, at speed.

  18. Actually the numbers are pretty staggering for a shower. A 10 minute shower with typical numbers uses about 4 kW-hr:

    The batteries on these e-scooters are something like 250 watt-hrs, or 0.25 kW-hr. That will take you at least 10 miles. You could probably go 200 miles on an e-scooter or e-bike using the energy of one shower.

    The energy use of showers also justifies air conditioning. I recall back when we had no A/C that I needed to shower twice a day during the summers. Even if you assume the water starts out warmer than in winter, and the showers might be a little shorter, that’s easily 1 kW-hr twice a day per person. In a 4-person household you’re using upwards of 8 kW-hr daily just for showering. An average room A/C might use 500 watts but it’ll only be on maybe 1/3 of the time to maintain temperature on an average day. That’s about 4 kW-hr per day. You can run two room A/Cs for the same power as very conservative showering uses. If you go with 4 kW-hr per shower you can run eight room A/Cs (two per person). Bottom line, air conditioning is likely energy neutral when looking at the big picture, even if environmentalists like to harp on it as a symbol of waste.

  19. Obesity is the new normal, but the morbidly obese aren’t walking more than a few shuffles. It’s sad, because humans are healed by walking, designed to walk, can be reasonably fit by walking a mile or two a day. Until post WWII almost all Americans walked miles every day without complaint, despite bad shoes, or lack of electric scooters. The domination of motor vehicles over public spaces is one of the main reasons walking has become so unpleasant, although loose dogs, fear of crime, intolerable walking spaces all contribute.

  20. Deeper Dive: You can trip over your own two feet, fall, hit your head, and die, too.

  21. Please give us the source for this! “a 2015 study by Ralph Buehler and John Pucher estimated that 2.25 cyclists die on their own bikes, and 5 bike-share riders die, for every 100 million miles in London and Paris.”

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Electric scooters on city streets. Photo: Swagtron

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