WaPo Is Wrong: Head Injuries Are Down, Not Up, in Bike-Share Cities

Image: Washington Post headline, at 1:39 p.m. Friday, showed a headline that said, incorrectly, that bike sharing cities saw an increase in head injuries. Image: Washington Post
The Washington Post ran a headline today erroneously claiming that cyclist head injuries increased in bike-share cities, when in fact head injuries declined more in bike-share cities than in cities without bike-share.

A Washington Post headline proclaimed today that cyclist head injuries have increased in cities with bike-share systems, based on a study published in the American Journal of Public Health. But University of British Columbia public health professor Kay Ann Teschke is challenging that conclusion, pointing out that the data cited by the WaPo actually leads to the opposite conclusion: In cities with bike-share systems, head injuries and injuries of all kinds have gone down.

“The message that bike-share is increasing head injuries is not true,” Teschke told Streetsblog. “The tone of the article suggests that head injuries go up. Really what is happening is that head injuries went down, non-head injuries went down — but non-head injuries went down more.”

The study was based on injury data from trauma center databases and registries in American and Canadian cities, collected over the same time period from both bike-share cities and control cities. A press release for the study said the “risk of head injury among cyclists increased 14 percent after implementation of bike-share programs in several major cities.” But to put the finding in plainer language, what the researchers actually show is that head injuries as a proportion of overall cyclist injuries rose from 42 percent to 50 percent in five cities after the implementation of bike-share.

As for the overall safety of cyclists following the introduction of bike-share, Teschke says the data in the article actually show that total head injuries fell more in the five cities that implemented bike-share than in the control group. Head injuries just didn’t fall as much as total injuries.

The AJPH article’s authors make cautious assertions that their research might build the case for helmet requirements with bike-share. The Washington Post’s Lenny Bernstein, meanwhile, wasn’t cautious at all:

A few weeks ago, in honor of annual Bike to Work day, I asked a simple question about why those terrific bike share programs don’t provide helmets to riders. There were a lot of understandable reasons — hygiene, cost, liability — but one thing all the cities I checked seem to argue is that bike share programs are very safe, much safer than, say, cruising around on your own bicycle. Their evidence was anecdotal, based on the tiny number of reports of injuries to cyclists who have taken millions of bike share trips nationwide.

Well, it looks like they are wrong.

A look at the raw data doesn’t support Bernstein’s gloating at all.

Click to enlarge. The raw data from a report about safety in bike sharing cities shows a decrease -- not an increase in injuries, in contrast to the report from the Washington Post. To make the comparison, you have to divide the pre-implimentation data by two, because the pre-implementation phase lasted two years, while post-implementation lasted one. Chart: University of Washington
The raw data from a report about safety in bike-share cities shows a decrease — not an increase — in injuries, in contrast to the report from the Washington Post. To make the comparison, you have to divide the pre-implimentation data by two, because the pre-implementation phase lasted two years, while post-implementation lasted one. Click to enlarge. Chart: University of Washington

In the cities that implemented bike-share, Teschke said, all injuries declined 28 percent, from 757 to 545. Head injuries declined 14 percent, from 319 to 273 per year. And moderate to severe head injuries also declined from 162 to 119.

Meanwhile, in the control cities that do not have bike-share, all injuries increased slightly from 932 to 953 per year — 6 percent. Head injuries decreased slightly — 4 percent — from 356 to 342. And moderate to severe head injuries increased from 181 to 192. (All the information can be found in the above chart, but you need to divide the pre-implimentation data by two to control for the fact that that period was twice as long as the post-implementation period.)

Teschke attempted to notify Bernstein of the problem with the article in the comments of the story, and he was initially dismissive. He has since admitted in the comments that she is right, but had not adjusted his piece substantially at the time we published this post.

Teschke said the AJPH report could have just as easily focused on how bike-share is associated with lower injury rates — both head injuries and overall injuries. Instead, the researchers, one of whom specializes in helmet research, chose to focus on this one piece of data — proportion of head injuries — to the exclusion of the larger picture: declining overall injuries. Teschke said she is planning to email the authors with her concerns and perhaps invite them to partner on a future study.

“I really feel badly that this wrong information is getting out there,” Teschke said. “I don’t really think the results support their conclusion much.”

35 thoughts on WaPo Is Wrong: Head Injuries Are Down, Not Up, in Bike-Share Cities

  1. What is even more remarkable is that the number of injuries went down even although cycling is up. This is the famous “safety in numbers” effect.

    All the bike-haters know full well that social or legal pressure to wear helmets is an excellent way of hassling people out of cycling. So we can now say this to these concern trolls:

    “The best way to ensure cyclist safety is through safety in numbers. That means making cycling the fastest, easiest and most convenient way of going from A to B. Which means Dutch-style infrastructure constructed to the Dutch CROW bicycle traffic engineering design standard. And it means no helmets or other hassling nuisances that make cycling less convenient. Which is why the safest place in the world to ride a bicycle is in The Netherlands, where almost nobody wears a helmet.”

    That is the way to cycling safety.

  2. Wait? Are you saying that people with PhD’s that did this report made basic “Statics 101” data manipulation errors in their conclusions and that it somehow got published making false conclusions?!?!

    You’re right! It’s clear as day! Talk about a JUNK conclusion!!! The data clearly show a decrease in all injuries after bikeshare!

    Sounds like they had the conclusion in mind before the study was done and that AIN’T science!

  3. Uhh, Teschke is the one who pointed out the problems with the research, not the one who wrote the study.

  4. Bernstein should be given a strong reprimand from his editor at the WaPo for spreading lies too!

  5. What is most fascinating is that the absolute number of injuries went down even when more people are cycling. So that the injury rate nose-dived.

    In city after city around the world we see the same three things leading to more cycling and less injuries:

    1. Bike share.
    2. Protected Dutch-style infrastructure.
    3. No social or legal pressure to wear helmets, hi-viz, etc.

  6. “Their evidence was anecdotal, based on the tiny number of reports of injuries to cyclists who have taken millions of bike share trips nationwide.”

    When the sample size is in the millions, it is no longer “anecdotal” evidence.

  7. What’s next? Is the Washington Post going to publish this statement:

    “FRA claims of railway safety are anecdotal, based upon the tiny number of reports of injuries to railway passengers who have taken millions of railway trips nationwide.”

    See how absurd and crazy it is!

  8. The study isn’t able to say if the injured people were using bike-share bicycles and it isn’t able to say if the people with head injuries were or were not hearing helmets. How is this helpful? The lack of good data for bicycle use in general is troubling.

  9. Thank you for saying exactly what was on my mind. I question the motivation of people, especially non-cyclists, when they mention head injuries as I know full well all they’re aiming towards is mandatory helmet laws. As we both know, all such laws will do is make cycling less safe overall by drastically reducing the numbers of people cycling. Ironically, they won’t even make things safer for those cyclists who choose to continue cycling by donning helmets. The most recent studies point to helmets being neutral at best in preventing injuries.

    I would love to know the proportion of severe head injuries in these studies where collision with a motor vehicle was involved. Helmets do squat to prevent head injuries in motor vehicle collisions. Moreover, even if they did help, the typical mechanism for disability/death in such collisions is blunt force trauma to major organs, sometimes but not always accompanied by head trauma. In layman’s terms, the person is often dead already in such collisions even if they sustain no head injuries whatsoever.

  10. Moreover, it doesn’t state how many head injuries occurred during a collision with a motor vehicle. That would certainly be relevant data. A helmet generally won’t prevent head injury in such a collision, nor will not wearing one make the likelihood of death/severe disability higher.

    Of course, things like that often don’t matter to the people pushing these studies because they seem to think helmets will prevent 100% of head injuries. I vaguely recall an incident in NYC some years ago where a cyclist had their head crushed under the rear wheels of a bus, and the media actually harped on the fact that they weren’t wearing a helmet, as if that would have mattered.

  11. There is a recent better study looking at the impact of bike share on a more relevant metric, which is…

    “sum of years of life lost owing to premature mortality (YLL) and years of healthy life lost due to disability (YLD)”

    They found bike share is good for middle aged to older males, and a wash for everyone else.


  12. I loved reading this comment to the original article:

    Tom has 20 pieces of fruit: 10 apples and 10 oranges. Bill has 10 pieces of fruit: 8 apples and 2 oranges.

    Washington Post headline: “Bill has 30% more apples than Tom”

  13. Lenny Bernstein: Anecdotal!
    Inigo Montoya: You keep using that word. I do not think it means what you think it means.

  14. WaPo is wrong … and in other news, frogs like water. Sadly, the paper that helped bring down Nixon has come a long way, and not in a good direction.

  15. WaPo was a cheerleader for the Iraq war. Whatever credibility they once had was lost long ago. Move along, nothing to see here…

  16. They also don’t report the total number of head injuries related to transportation, although they surely had that data. If bike share reduced driving or increased awareness as the ‘safety in numbers’ theory suggests, they might have measured a decrease in all injuries as well. This study, and the reporting on it, makes me choke up with anger. I truly hope that no city decides to forgo bike share or make it more difficult as a result of this mess.

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