Helmet safety claims overstated

Thanks  to WABA : “The federal government is withdrawing its long-standing claim that bicycle helmets prevent 85% of head injuries, in response to a petition filed by WABA under the federal Data Quality Act.”

Congratulations to WABA (a Washington, DC, Area Bike advocacy group) for holding the government to account. While this, of course, is not going to end the “helmet wars”, it will hopefully move us back towards evidence-based investigation of bicycling transportation safety.

The particular US government agencies involved are the CDC and NHTSA who confirmed by letter they will stop disseminating the oft-quoted 85% figure. The NHSTA will, however, continue to claim helmets are “the single most important way to prevent head injury resulting from a bicycle crash”.

The WABA article is, by the way, a good explanation of what can go wrong with case-control type statistics that often are the output of public health community researchers. These types of claims are often(always?) behind the most stunning soundbytes, see e.g. cycle-tracks-are-NINE-TIMES-safer-than-roads.

Speaking of helmets, there was a recent long article in bicycling magazine; which is really interesting stuff about the current CPSC-mandated safety standards might be limiting advances that would allow different (different than the omnipresent EPS) materials, and better protection, especially from concussion.

Bike Share / CitiBike and helmets

One doesn’t imagine that bikeshare patrons often have a helmet with them, I didn’t when i visited Madison, WI summer of 2014 and partook of  B Cycle  there.

This is schadenfreude, but apparently last year Prof. Pucher predicted (mentioned below in a NYPost opinion piece) that CitiBike could cause bicyclist fatalities to triple in NYC. There apparently were ~ 20/year in the pre-citibike period. Now thefirst full year crash results are in and there have been zero fatals among CitiBike riders (in 15Million miles of useage!), and a total of 100 crash reports, i.e. a rate of 150,000 miles per incident…

Citi Bike ‘heading’ for a fall July 1, 2013
Mayor Bloomberg is often portrayed as an overprotective nanny, restricting cigarettes and soda sizes. So what about a bike-share program that lets novice riders loose on New York’s busy streets without helmets?
About 20 cyclists are killed in accidents in New York City each year, but Rutgers University Professor John Pucher says the number of injuries and fatalities could triple in the Citi Bike program’s first year. So far, there have been reports of only three minor accidents involving Citi Bikes.
Bloomberg spokesman John McCarthy says that the city has created hundreds of miles of bike lanes to protect cyclists and that enforcing helmet use would be impractical.
Under state law, only delivery riders and children under 14 are required to wear helmets.

Moving forward in time, NYC as a whole in 2015 reported 14 cyclist-MV fatalities, down from 20 in 2014.

WSJ editorial board member Dorothy Rabinowitz in an oddly-vitriolic tirade coins the term “all powerful bicycle lobby”; and mentions citibike may times in her bizzarre rant dated 5/13/2013. You just can’t make stuff like this up, here are my favorite excerpts:

“…New York’s best neighborhoods are absolutely begrimed by these citibikes…” “moderator: It’s not just shocking, it’s (presumably citibike racks) also a fire hazard in some cases the fire trucks can’t get into subway stations” “moderator (quoting car-ped crash stats): so is there a chance the danger is overblown? Rabinowitz: oh well look, before this (before, apparently referring to before citibike) it was dangerous, before this ever citizen knew, who is in any way senescent, that the most important danger (presumably to peds) in the city is not the yellow cab but the bicyclists who veer in and out…”.

She’s also mad that cabs have plaques admonishing passengers to not open their doors into traffic (which, i imagine is a legal requirement; it is in AZ).

Update on Citibike 6/12/2017: The first ever CitiBike rider fatality has been reported. CitiBike has been in operation in NYC since May 2013. Unhelmeted, it was dutifully reported. No word as to whether a helmet would have prevented the rider’s death. He was crushed to death by a 20+ ton bus. Police have said the cyclist “swerved”, however Gothamist reported surveillance video that surfaced later shows otherwise. NYPD have a track record of favoring motorists in bike-MV, or bike-ped collisions, e.g. Felix Coss was killed walking in a marked crosswalk with a green light, and NYPD says the pedestrian assumes the risk. Update 10/2018; the bus driver was convicted at trial of a misdemeanor and a violation,. See remarks at crash-not-accident. Video depicted the bicyclist going straight ahead (no swerve — where did that come from, did the driver lie to police?)

Divvy / Chicago Bikeshare

A Feb 2015 article in dnainfo.com/chicago , my emphasis:”Divvy users have logged more than 3.2 million rides in the last 2½ years, and the small number of injuries suffered by riders may surprise skeptics, particularly because helmets aren’t required or even included with the rentals. But the Divvy data lines up with national statistics showing bike-sharing cyclists are generally safe, or at least lucky”  …Of the 18 reported incidents involving Divvy bikes, one involved a cyclist hitting a pothole, and another person suffered scrapes when the chain fell off a bike”.  Lucky? really? 3.2 million miles of luck? I don’t think they listed a tally, they mentioned a couple of what would be called “incapacitating” injuries; the most serious involved an apparently impaired divvy bicyclist.

In any event 3.2million/18 calculates out to one incident per 180,000 miles.

July 1, 2016 — Divvy Bike Rider Killed in Avondale Crash ID’d; Believed to be First US Bike-Sharing Death. Victim is 25 y.o. Virginia Murray. The article describes a classic right hook — according to the article there is surveillance video that showed the rider riding up the right side of a stopped flatbed truck (waiting at a signal I imagine); the truck then turns right, and collides with the bicyclist who was also turning (or intending to turn?) right. According the to the article the rider was wearing a helmet (which should be irrelevant, she was presumably crushed to death by the truck) but for the purposes here with bikeshares and helmets, I mention it.  According to the article there are a lot of “accidents” at this corner, and mentions — twice — “There are no bike lanes at the busy intersection”… underlying a misunderstanding of crash modes and right hooks. Bike lanes, if anything, exacerbate right hooks. A longer article on chi.streetsblog.org refers to the video, but hasn’t see it. A Chicago Bike lawyer has a description illinoisbicyclelaw.com, but it sounds as though he hasn’t seen the video, either; he describes it as a standard right-hook and quotes a local ordinance stating an “overtaking” driver must yield to any bicyclist in such a situation (but was the truck driver overtaking?).

Phoenix / GRiD Bikeshare

A tidbit of very preliminary information was in councilwoman Thelda William’s newsletter:

Also, in November 2014, the GR:D Bike Share Program was launched. From January 1 to September 30, 2015, there have been 28,228 trips taken by 5,478 riders who have ridden a total of 48,583 miles. Since system launch, there have been very few operational problems, no bicycles have been lost or stolen, and there have been no reported traffic collisions involving GR:D bicyclists. Service continues to improve and expand.

BikeShare in general

newish (march 2016) study commissioned by CalDOT Bikesharing and Bicycle Safety, from the abstract, my emphasis:

Bikesharing has some qualities that appear inherently unsafe for bicyclists. Most prominently, helmet usage is
documented to be quite low in most regions… Finally, researchers conducted an analysis of bicycle and bikesharing activity data, as well as bicycle and bikesharing collisions to evaluate injury rates associated with bikesharing when compared with benchmarks of personal bicycling. The data analysis found that collision and injury rates for bikesharing are lower than previously computed rates for personal bicycling



This tidbit was interesting, I was unaware the BHSI was a sub-association of WABA, and interesting take about the slowing trend:

In 2013 the pace of new helmet laws has slowed to almost zero. Attempts to extend laws to cover adults have been unsuccessful. Urban riders are increasingly questioning the need for helmets, and certainly the need for helmet laws. WABA, our parent organization, has taken a position opposing the extension of the Maryland state helmet law to adults. A pendulum is swinging. We expect it to swing back eventually as injuries show up, but the positive experience with shared bicycle programs has raised basic questions about the need for helmets, and younger riders are reconsidering. We regard all that as a fashion trend and remain convinced that bike riders need helmets.

And their more general approach to mandatory helmet laws:

We have always been a lot more enthusiastic about promoting voluntary use of helmets than promoting laws, and it would appear from the list above that most U.S. states and localities are too. Even seatbelt laws that have been around for a long time are mostly secondary offense laws limiting enforcement to occasions when a driver has been stopped for something else. Helmet laws can be useful, but given the problems with enforcing them they will probably not work well in most places until more riders have accepted the need for wearing a helmet. So we favor a stronger push for voluntary usage than for passing new helmet laws, and our Web site has always reflected that attitude.

Some California Data

In spring of 2015, CA floated a mandatory helmet law SB192; calbike.org put together some stats mostly about how rates of cycling over relatively large amounts of time have increased quite a bit; i.e. injury rate has dropped significantly. The bill ultimately got amended to replace the mandate with something about safety studies of helmet use.


It has been observed that Dutch cyclists have a very low rate of helmet usage, and at the same time enjoy a relatively low level of injuries and fatalities per distance traveled. See e.g. Pucher 2008 Making Cycling Irresistible: Lessons from The Netherlands, Denmark and Germany : quoting Dutch Bicycle Council figures “in the Netherlands, with the safest cycling of any country, less than 1% of adult cyclists wear helmets, and even among children, only 3–5% wear helmets”. Among mode-share advocates, it is believed that mandatory, or even high levels of, helmet use are detrimental to mode-share; there are various empirical and psychological explanations for this. With this grain of salt, consider this Dutch paper:

Overestimation of the effectiveness of the bicycle helmet by the use of odds ratios by Theo Zeegers  presented at International Cycling Safety Conference 2015 concluded  “Any case-control study in which the control is formed by hospitalized bicyclists is unreliable and likely to overestimate the effectiveness of the bicycle helmet”

Onestreet has a nice collection of factoids about the The Problem with Bicycle Helmets, and why “dangerising” bicycling is counter-productive.

3 thoughts on “Helmet safety claims overstated”

  1. Steven Goodridge commented about the NTSB Safety Research Report – Bicyclist Safety on US Roadways: Crash Risks and Countermeasures on their facebook page:
    I’m usually a big fan of the NTSB and its scientific process, but here the NTSB clearly dropped the ball. The summary report fails to assign appropriate priority to the biggest contributor to the elevated bicyclist fatality and severe injury rates in the US: High vehicle speeds on the roads that cyclists must use to go anywhere. The availability of usable lower-speed alternative routes and/or engineering of lower speeds on critical routes is a much stronger predictor of bicycling safety than helmet use, visibility technology, and even bicycle-specific engineering. By all means, let’s use helmets and lights, and follow the rules of the road, but not at the cost of taking our eyes of the biggest problem we face in the US: the engineering and enforcement of our must-use shared streets as high-speed motorways. Other nations have figured this out. It’s long past time for the US to catch up.

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