Tag Archives: helmets

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.

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.

Data Collection of Bicyclist Helmet Use in Crashes

I have some questions/concerns/misgivings about helmet usage as it relates to bicyclist safety and crash reports. It seems to me that it is not well-reported…

Arizona Crash Report

Curiously, given the hoopla intense interest surrounding bicyclist helmet usage, there is NO place on the ACR to report whether or not a bicyclist was using a helmet. There is a block for each traffic unit(4dd) and passenger(5c), SafetyDevice  lists things like helmet/airbag/seatbelt and so forth. However, this block is always supposed to be coded 0/Not Applicable, and is explicitly never to be 1/None Used, or 5/Helmet Used for pedalcyclists. See p.23, 26 of 2010 Arizona’s Crash Report Forms Instruction Manual.

Clearly this is often coded not according to the manual, see below for some live data e.g. from 2010. We might guess that the 10% or so that say Helmet Used probably does mean those bicyclists had helmets, and likewise probably the 35% that said None Used probably means not helmet. But the other 55% is (from the data) anybody’s’ guess.

There is likewise no place on the ACR to code for nighttime crashes whether or not a bicyclist was using required lighting equipment (a front headlight or a rear taillight/reflector).


For 1994 through 2009; all persons including bicyclists and other pedalcyclists used the P10 Restraint/Helmet Use field. The column was called REST_USE in the person table.

From 2010 and later, this info was moved to a whole new dataset, the SafetyEq table. the column name is MSAFEQMT; and it’s slightly annoying because it’s indexed by ST_CASE (i.e. the case number), and person number. There can be any number of records for any given person.

The field is called NM13 Non-Motorist Safety Equipment “This element indicates the safety equipment that was used by the non-motorist
involved in the crash”, in the FAR Manual. In the FAR Validation Manual, there’s an elaborate confusing explanation of differentiating between Not Reported and Unknown. Allowable values are:

  1. None
  2. Helmet
  3. Reflective Clothing (jacket, backpack, etc.)
  4. Protective Pads Used (elbows, knees, shins, etc.)
  5. Lighting
  6. (not used)
  7. Other Safety Equipment
  8. Not Reported
  9. Unknown if Used


For reference, you can see mmucc.us‘s field P23 Non-Motorist Safety Equipment from (MMUCC is a nhtsa-funded group that sets standards for data collection on traffic crash reports). This is consistent with FARS definition; except that mmucc says only two may be selected for any person, and FARS allows any number to be selected (theoretically, the vast majority have either one or two selected).


Rate of bicycle-related fatalities significantly lower in states with helmet laws?

Annoyingly I cannot find the actual article by searching The Journal of Pediatrics website jpeds.com/search/quick so we may never know… Apparently they’ve taken the tactic of flooding the internet with press releases that don’t even mention the name of the article.

In any event I am having a hard time seeing that helmet use data is well-reported, please see data-collection-of-bicyclist-helmet-use-in-crashes; if the data is not accurately collected and reported, studies such as these that simply mine FARS data seem really suspect.

From a press release (my emphasis): “Existing research shows that bicyclists who wear helmets have an 88 percent lower risk of brain injury, but researchers at Boston Children’s Hospital found that simply having bicycle helmet laws in place showed a 20 percent decrease in deaths and injuries for children younger than 16 who were in bicycle-motor vehicle collisions”

I think helmets are great; but it seems to me they are being over-sold. Here there is a general claim of an enormous reduction in TBI, and then further that there is a modest safety bump in JUST HAVING A LAW. hmmm. so many questions.

  1. what does rate mean? my guess is it’s population based; it would be far better if it were exposure based. I wouldn’t be surprised to see pediatric exposure has been declining. The study I noted at effects-of-bicycle-helmet-laws-on-childrens-injuries from National Bureau of Economic Research made more sense to me: helmet laws = less cycling = lower “rates” of death/injury mostly because most people figure rates based on population and not exposure
  2. obviously, what’s really more interesting is compliance rate, and not just whether or not a state has a law. plus how do they handle local laws(e.g. tucson and a few other Arizona cities have a minor helmet law, though there is no state law).
  3. helmet data in FARS; the last time i remember checking , there were a *lot* of “unknowns” in the helmet yes/no box. This should be pretty easy to check, at least for 2010 and 11 now that I have my own FARS database up and running.
  4. Another study out of Canada and published in BMJ found helmet laws had little to no effect; what they describe as an underlying baseline effect. “…  the incremental contribution of provincial helmet legislation to reduce hospital admissions for head injuries seems to have been minimal.

In case you were wondering here is the list of Arizona cities/jurisdictions that have MHLs: mandatory-bicycle-helmet-laws-in-arizona

Effects of Bicycle Helmet Laws on Children’s Injuries

Those seeking to improve the situation of bicyclists, PARTICULARLY through laws or regulations, should first consider the possibility of unintended consequences…

Helmets protect rider’s heads. Bicycle riders sometimes suffer head injuries. So it would go without saying that mandatory helmet laws would improve cyclist safety, right? Well,maybe not when substitution effects (or other human nature effects) are factored in. Mandatory helmet laws have the unintended consequence of suppressing cycling. Effects of Bicycle Helmet Laws on Children’s Injuries — by Pinka Chatterji, Sara Markowitz found children cyclist’s head injuries are down, and so are other injuries, and so is the amount of cycling; from the abstract:

we find helmet laws are associated with reductions in bicycle-related head injuries among children. However, laws also are associated with decreases in non-head cycling injuries, as well as increases in head injuries from other wheeled sports. Thus, the observed reduction in bicycle-related head injuries may be due to reductions in bicycle riding induced by the laws

 More broadly, people behave differently when they are helmeted; people (drivers) around cyclists behave differently depending on whether or not the cyclist is helmeted. These are human nature effects and very hard to quantify, but exist nonetheless. Risk homeostasis affects both riders and drivers.


Mandatory Bicycle Helmet Laws in Arizona

The state of Arizona has no mandatory helmet use law for bicyclists; there are a few municipalities that have their own rules.
Specifically,  I believe this is a correct list at  bhsi.org, current as of mid-2011 (and I see nothing in the pipeline):

Municipality applies only to Year Enacted
Flagstaff Under 18 2010
Pima County Under 18 1995
Sierra Vista Under 18 1995
Tucson Under 18 1993
Yuma Under 18 1997

Noteworthy: as I scan the whole list of all states, I don’t see any state that mandates adult helmet use, only various ages of minors.

Motorized Bicycles

The city of Tucson (and possibly Pima county?) has helmet rules applying to motorized bicycles requiring helmet use; but if i recall correctly they completely

Although as of this writing (Nov 2016) this proposal hasn’t been adopted, the City of Tempe has floated rules which would make riders below 18 years to wear a helmet when operating various forms of motorized bicycles; and operators must be at least 16 years old.

In case you were wondering, Motorcyclists…

According to iihs.org there is a state law for under-18 year-old motorcyclists — including “motor driven cycles” (< 5hp). The statute is 28-964; and a quick read says that “motor driver cycles” do not include either mopeds or “motorized bicycles” but I’m not really sure. Here is some material from www.usff.com/hldl/hlstatutes/arizonahl.html (I removed the link, if you want to visit the site, copy and paste it… as of Feb 28, 2013 this link is listed as “may harm your compter” by google), and anti-motorcycle mandatory helmet law site.