The Chainlink

My uneasy relationship with helmets


I am in favor of bicycles, bicycling and bicycle safety. I am opposed to bicyclists sustaining injuries and particularly head injuries that result in traumatic brain injury. More bicycles on streets and roadways make all bicyclists safer. Mandatory helmet
laws increase the rate of helmet use but decrease the number of bicyclists. The
health benefits of riding a bicycle far outweigh the risks of injury or death
(in “life years”). Bicycle helmets represent a design compromise that reduces
effectiveness in a crash in favor of lighter weight, comfort and ventilation.
If you are relying on a helmet to keep you safer while riding a bicycle, you
have skipped a number of important steps that can more effectively keep you “safer.”


I ordinarily keep my opinions about bicycle helmets to myself. I never tell anyone not to wear a helmet, though I sometimes wish the helmet people would reciprocate. The only reason I’m going “public” now is because the Active Transportation Alliance has
adopted a policy of making helmet use mandatory for its various fundraising
and/or sponsored events. The language currently being used is “I agree to wear a helmet suitable for cycling at all times during the bicycle tour. Those who refuse to
wear a helmet will not be permitted to ride and will not receive a
refund.”  The attorney side of me suspects this is an insurance underwriting requirement and the ATA needs to include this language to get a break on its liability premium (or possibly, a requirement to get any kind of coverage at all). And lest any of you think that the insurance underwriters are trying to make everyone safer, additional
requirements imposed on the policyholder are typically included in policies to
form a basis for excluding coverage.
The bicyclist side of me is disappointed that an organization which professes
to “advocate for transportation that encourages and promotes safety, physical activity,
health, recreation, social interaction, equity, environmental stewardship and
resource conservation,” has adopted a policy which runs contrary to that
mission statement. (I just became aware that “Bicycle Chicago Meet-up” and
Lee’s Big Shoulders Neighborhood Tours have the same requirement.)


I don’t want this post to be about me, but by way of background, my bicycling “experience” pre-dates the widespread use of helmets
(probably even the old “hairnets”). When I was a kid, you wore a helmet when you played football and when you batted in baseball, but that was pretty much it. In high school

and college, I competed in gymnastics (trampoline, no less), rugby and ski
racing - never wore a helmet, and neither did anyone else. My non-competitive
unhelmeted activities during this period of time included freestyle skiing with
lots of inverted aerials, and lots of vertical mogul runs. Bicycled some in
college, but never wore a helmet. Always wear a helmet snowmobiling, but
seriously, that’s a little like requiring people to wear a helmet when they go
skydiving. How did people survive such ultra-hazardous activities in the
pre-helmet dark ages? We took extra care not to hit our heads when we fell
down. Sometimes the old ways are the best ways.


This is not an academic paper for peer review, so I’m going to omit cites. If you’re really curious about one of them that you can’t find yourself or feel the need to rip on me in general, let me know and I’ll try to find it again. I know there are a lot of engineers and health care professionals on the chainlink, and I hope this post yields some constructive
criticism and feedback.


Bicycle helmets are mostly designed for slow, vertical falls. The testing methodology is to drop the weighted (11 lbs/5 kilos) helmet from a height of 1.2 meters onto a round anvil and/or a curb-shaped anvil and from a height of 2 meters onto a flat anvil. The headform measures the amount of impact attenuation when the helmet comes to rest, expressed in joules. A helmet which “passes the test” can permit a maximum of 98 joules at the headform. Failure threshold is 300 g, which happens to be the level at which you can expect to lose consciousness, and probably suffer some injury which hopefully will not be permanent.


Real world impacts are going to look a lot different from the testing methodology in that they are much more likely to include: multiple impacts, irregularly shaped “anvils,” and rotational forces (think crack the whip or water skiing outside of the wake when the boat turns). Real world impacts are also much more likely to occur with some significant horizontal speed (which has both advantages and disadvantages).


I bought my first helmet in about 1988. It was a thick styrofoam, poorly vented Specialized helmet which had a nylon fabric cover stretched over it and bore certification stickers to the 1984 Snell and ANSI standards. The unfinished styrofoam design was abandoned within five years for the hard shell finish due to the observation of increased neck and brain injury related to rotational forces exerted upon a helmet which was too “grippy” when it contacted pavement.


Bicycle helmet design must strike a balance between fashion and function. As the pressure has built for manufacturers to design “cooler” helmets (both from an aesthetic and ventilation standpoint), more and larger vents have been cut into the helmet surface. This has resulted in helmets which are indeed cooler and lighter, but which lack the structural integrity of my ugly old Specialized helmet. And penetration risk from rocks and tree branches when mountain biking?: Forget it; not even tested anymore; too many vents. Snell standards are gone, the certifying bodies in the U.S. are now CPSC and ASTM both of which require less energy attenuation than the Snell 95 standards
did. If you’re really serious about wearing a helmet to protect yourself from
traumatic brain injury, buy yourself a good, full-faced Arai, Bell or Shoei
motorcycle helmet-much better energy attenuation, and you also get the added
benefit of protection from facial injuries.


I wear a helmet approximately 25% of the time I ride a bike. My decision to wear a helmet is usually based on: a) likelihood of sustained speeds in excess of 18 mph; b) exceedingly long rides (>6 hours); and/or c) riding with a lot of strangers. I ALWAYS wear a helmet when I ride a mountain bike on trails. The only time I have ever hit my head when bicycling was when I was wearing a helmet. It’s not that I’m such a genius at predicting crashes, it’s simply because a helmet adds an additional 2-3 inches to the
radius of my head and that confuses my muscles and my sensory nervous system. I
have spent a lifetime “learning” where the perimeter of my head ends and I
can’t rewire my perceptual system to account for that extra 2-3 inches. I have
never been hit by a car, but I’m not counting being doored three times over the
years.


Fear is a very effective marketing tool. Whether you’re Rahm Emanuel not wanting to let a good crisis go to waste, or you’re the Bush administration trying to head off the impending invasion of the U.S. by Islamic extremists, a lot of things get “sold” in this country based on an inflated perception of danger. Bike accidents result in approximately 540,000 emergency room visits in the U.S. every year. Of those, 67,000 (12.4%) involve head injuries, and 8375 involve brain injuries [TBI] (1.5%). I can’t find the exact cite for this one folks, but it’s fairly representative of any given year in
the U.S. I’m going to make a pure guess that emergency room visits as an
accident index result in underreporting the total number of bicycle accidents
by a minimum of a factor of three; i.e. there are 3 times as many bicycle
accidents in the U.S. each year and that for every one that sends someone to
the emergency room, another two go unreported or at least don’t result in a
trip to the hospital. I’m also going to guess that an accident serious enough
to result in a TBI is unlikely to result in no hospital visit, so the 8375 TBI
number is probably pretty close to accurate. If this data and these guesses are
true, your risk of TBI is about 0.5% for any given accident, and probably even
lower than that.


Riding a bicycle can improve cardiovascular fitness and improve Body Mass Index, but it doesn’t change certain hard-wired physiological traits or cognitive functions that assist in making you a “safer” bicyclist. We all have differences in strength (including the composition of slow-twitch vs. fast-twitch muscles), balance, visual acuity, (including depth perception and ability to detect motion), hearing, proprioception, and judgment, to name just a few.  I have seen at least a half a dozen bicyclists in the past week, after dark, wearing a helmet, with no lights on the front or the back of their bicycle. I have told two of them they’re going to need a bigger helmet.


As stated, I am opposed to head injuries and particularly traumatic brain injuries. My brain has remained a solid second on my list of favorite organs since adolescence. If I’m ever in a bicycle accident with a car, I want to be dressed like the guy in “The Hurt Locker.” Most studies of the efficacy of bicycle helmets have found them to be effective at reducing the risk of head injury. In my estimation, that takes the risk down from remote to infinitesimal. 


Mandatory helmet laws increase the rate of helmet use, but reduce the number of cyclists on the road (Australia, New Zealand, Canada - British Columbia and Nova Scotia).


More cyclists on the road make all cyclists safer. In 1994, 796 bicyclists were killed in crashes with motor vehicles; in 2009, 630 bicyclists were killed in crashes with motor vehicles (-21%). Trips by bicycle have increased from 0.7% in 1990 to 1.0% in 2009 (+43%).


Portland reported this year that their rate of helmet wearing has increased to 80%, all through promotions and peer pressure. I have no problem with encouraging people
to wear helmets, strongly recommending that people wear helmets, but REQUIRING,
and EXCLUDING?  Can’t we all just get along?

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Replies to This Discussion

Permalink Reply by Brendan Kevenides on October 29, 2010 at 3:33pm
Well, yes they are. The report referenced in the Freakonomics blog states, "Their research first confirms earlier research that “helmet laws significantly reduced bicycling fatalities among youths age 0-15 (i.e., youths who were directly treated by most states’ age-16 helmet laws) by about 19 percent.”

Their research further suggests “that helmet laws significantly increased youth helmet use by 29-35 percent.”

But: “There is also robust evidence for an unintended and previously undocumented mechanism: helmet laws produced modest but statistically significant reductions in youth bicycling participation of 4-5 percent.”

Again, a small (if any) reduction in cycling vs. a dramatic reduction in deaths among children is a reasonable trade off I'd take. Mandatory helmet laws seem to me to offer a significant net benefit.

Brendan.



Kevin Conway said:
Ain't statistics grand?


Brendan Kevenides said:
Thanks, Kevin.

Interesting. A 2010 Canadian study in the report you provided from the Bicycle Helmet Safety Institute concluded, "Canadian youth and adults are significantly more likely to wear helmets as the comprehensiveness of helmet legislation increases. Helmet legislation is not associated with changes in ridership.." There are other studies referenced that either demonstrated or speculated that mandatory helmet laws do or could reduce the number of cyclists. However, a smallish reduction in ridership is, in my view, overwhelmed by the down right spectacular reduction in deaths, especially among children, seen pretty much everywhere when helmets became mandatory.

I took the following from the report: (1) Mandatory helmet laws greatly increase helmet use, especially among children; (2) Wearing a helmet dramatically reduces your chances of death in a bike accident; and (3) It is not clear that mandatory helmet laws reduce ridership. According to a study published this year, it does not.



Kevin Conway said:
Yup. Courtesy of the aptly named Bicycle Helmet Safety Institute.

Here's a link to articles specifically dealing with Western Australia.


Brendan Kevenides said:
"Mandatory helmet laws increase the rate of helmet use, but reduce the number of cyclists on the road." Kevin do you have a citation for this?

I think I am for mandatory helmet laws. (I could perhaps be talked down from this position.)

Thanks for this interesting post Kevin.

Brendan
Permalink Reply by Minh on October 29, 2010 at 3:59pm
Correlation does not imply causation... and if you are going to quote statistical data you will need to link to the sources.
Permalink Reply by Brendan Kevenides on October 29, 2010 at 4:02pm
A state wide mandatory helmet law would apply to children only. No state law mandates that all adults wear helmets, and the vast majority of local ordinances mandating helmets apply to children only. The pending mandatory helmet bill in the Illinois Senate would only apply to children.



iggi said:
damn americans and your right to choose...
Permalink Reply by S on October 29, 2010 at 4:23pm


Minh said:
Correlation does not imply causation... and if you are going to quote statistical data you will need to link to the sources.

Strong consistent correlation between two events is can be taken as causation between the two events or a common underlying cause. That's as good as it gets even in the hard sciences.

Permalink Reply by Gin on October 29, 2010 at 5:12pm
As a general rule, I wear a helmet, esp now that I am a mom. I get aggravated when I see non helmeted parents biking with helmeted kids. It's not just about do as I do and as I say, but also that kids do better when parents don't have head injuries.

But sometimes we are lax. This summer, at a block party, Miguel (3 at the time) was cruising up and down the street on a friend's bike with training wheels. Up and down, sometimes fast. No helmet on. Not more than two minutes after I thought: "He should probably have a helmet on" I see him super slow mo crash. Forehead on pavement. Lots of tears and ice followed by golfball on head.

Data point of one, I know.

Happy Friday!
Permalink Reply by Lee Diamond on October 29, 2010 at 8:50pm
Speaking as someone that has group rides, requires helmets, and has insurance that requires that I require helmets, I feel it is the smart thing to do. I am severely allergic to fights with insurance companies and lawsuits, and both are things I try to minimize, like brain injuries.

I personally always ride with a helmet, and have always encouraged the use of helmets at my rides, but now must require it, full-stop, or I can't do them anymore. Such is the life of the insured, but it isn't a moral problem for me at all to require them. I feel it is a reasonable request for a group ride, that it isn't any more an imposition, than asking someone to wear a seat-belt on an amusement park ride, etc. I also provide them, free of charge for any that show up without them, because I want everyone to enjoy the ride and I am sad that someone such as yourself (Kevin) feels you should boycott a ride over that, but I understand your feelings.

I also have a different perspective as I am a father of a child with a brain injury. I would be the last person to lump every person with a brain injury together, but there are many common traits, even as different and complicated as their effects and treatment may be. Jackson's injury was caused by a reaction to one of his vaccines and the subsequent lack of oxygen to his brain when he stopped breathing. During the first several weeks we were in the hospital and eventually when we were in the neurology department, we met and were surrounded by people with brain injuries and their families. The majority of the injuries were the result of trauma to the head, not a medical trauma such as our son's, and also oxygen depravation. If anyone can tell any difference between what caused an individual's brain injury, I don't know how. Anyone that was in the acute care hospital for brain injury was in a seriously bad way, and while there are many levels of recovery, and it is hard to predict anyone's eventual state after an injury, the effects were always devasting, rehab was always slow, and recovery was a lifelong endeavor for most.

Now we live with this and it is our new normal. It is a completely altered world from before then and it makes me realize over and over that it is the people around us who care the most about us that will also live every day of their lives, taking care of us because of our decisions, things that happen to us, etc. You can't reduce the risk entirely, but you can bring it down, and I wear a helmet for my own sake, but also because what would happen to my family if something happened to me? I love my son and don't live with any regret over the sacrifices we have made and the troubles we have gone through. They are still nothing compared to what he endured and endures every day, so I am still blessed with him and am inspired by him, so I can not complain in that light.

I don't try to get preachy if i can help it. I don't rag on people for eating meat or driving cars or not having lights when they bike or not wearing a helmet, but I am greatly in favor of people doing everything they can to come home safe, and that absolutely includes wearing a helmet. I think the light concerns are valid, but I don't think anyone advocating helmet use is against the use of lights.

In my realm, I am also glad that the insurance requirement removed the ambiguity of it all for me, but am sad that many won't be joining us because of helmets being required. Oh well....there are many not joining us all the time for many reasons, so, so be it.


And no ragging on Kathy please.

Cheers - Lee
Permalink Reply by Joe Studer 8.0 mi on October 29, 2010 at 10:09pm
Great discussion! Thanks for the original post, Kevin (as always, an idea well presented), and thanks also to the many people who contributed such thoughtful comments.
Permalink Reply by Mark Kenseth on October 30, 2010 at 10:13am
Permalink Reply by Juan 2-8 mi. on October 30, 2010 at 1:42pm
Dammit! I was just thinking of posting this, haha.

Mark Kenseth said:
Permalink Reply by Ed on October 30, 2010 at 2:39pm
I have never been an "ALWAYS" bicycle helmet wearer, but I just may have been converted.

Heading back to Union station last night after CM, I took a spill I never saw coming. Before I knew it, I was face planted on the concrete.

Forget having time to "fall correctly", I spent all my head-first-into-the-pavement time trying to figure out why my front wheel sunk right into the road! Did I miss a hole? Did my wheel collapse?
Luckly, I had my hemlet on, and the helmet and my chin took pretty good hits. My chin didn't fare as well as the helmet, which did great! (see pics below)

Got up quick, had to find out what happened. I had just ridden into freshly poured concrete. Amazing how fast that will swallow up a wheel and toss you.

True, there were lots of clues I should noticed about the fresh concrete, but at the time, I never expected it.
You just never know.


Permalink Reply by Davo on October 30, 2010 at 3:11pm
I posted it earlier but I didn't snazz the post up enough. I love how video shows someone getting hit from behind. I'm no expert but my guess is that happens far less than other collisions.



Juan Dominguez said:
Dammit! I was just thinking of posting this, haha.

Mark Kenseth said:
Permalink Reply by Davo on October 30, 2010 at 3:13pm
I'm glad you're ok but all your story needs is you crashing in a fruit cart or through a pane of glass that two guys are carrying across the road


Ed said:
I have never been an "ALWAYS" bicycle helmet wearer, but I just may have been converted.

Heading back to Union station last night after CM, I took a spill I never saw coming. Before I knew it, I was face planted on the concrete.

Forget having time to "fall correctly", I spent all my head-first-into-the-pavement time trying to figure out why my front wheel sunk right into the road! Did I miss a hole? Did my wheel collapse?
Luckly, I had my hemlet on, and the helmet and my chin took pretty good hits. My chin didn't fare as well as the helmet, which did great! (see pics below)

Got up quick, had to find out what happened. I had just ridden into freshly poured concrete. Amazing how fast that will swallow up a wheel and toss you.

True, there were lots of clues I should noticed about the fresh concrete, but at the time, I never expected it.
You just never know.


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