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.
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%).
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Killing 'em with kindness, Matt?
Matt M. said:Dear Kevin,
Screw you. I've seen the effects of head trauma as a result of cycling accidents and it's nothing to debate about. Wear a fucking helmet, moron.
Sincerely,
Matt M
I think I am for mandatory helmet laws. (I could perhaps be talked down from this position.) I am for such laws because I want parents to require their children to wear helmets while biking. Kids are more liking to hit their heads in low speed crashes. Also, if children grow up wearing helmets it becomes no big deal.
The logic here is a bit backward. If proposed mandatory helmet laws are to have any significant effect they'd be aimed primarily at adults. Bones lose mass and density and become more brittle with age, thus making adults more susceptible to head and brain injury from impact.
Brendan Kevenides said:I think I am for mandatory helmet laws. (I could perhaps be talked down from this position.) I am for such laws because I want parents to require their children to wear helmets while biking. Kids are more liking to hit their heads in low speed crashes. Also, if children grow up wearing helmets it becomes no big deal.
...I believe the rationale for targeting children with mandatory helmet laws is to change the "culture" through evolutionary change. It's the "old dog/new trick" conundrum.
I also think all pedestrians in the Loop should be required to wear helmets. If you work in the Loop, I'm sure you've see all the jaywalkers/people absorbed in their cell phone conversation/absorbed in their texting/etc. walking right into the street without so much as looking right/left. Obviously, they would have to be taught to lead with their head so the impact would be to the helmet . . .
I wear magical hats and think others should, too, because why not. The most interesting thing to me, though, is always when you hear someone say, as someone here did, that while they got a concussion in a wreck, their helmet protected them from traumatic brain injury. A concussion is by definition a traumatic brain injury! If helmets were really effective people wouldn't get concussions while wearing them. Such is the power of faith in the magical hat, though, that even when they don't work they're credited for working.
Magic force-field.
Do I believe they do more good than harm? Probably -but only if they do not give the rider a false sense of security or feeling of invincibility. Helmets give such a minor increase in armor-protection to a limited area of the head in a very limited type of impact that ANY change in the behavior of the rider towards increased risk-taking will easily negate their fractional utility as a safety device and quickly become an albatross upon the rider's head instead of the magic talisman they believe it to be.
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