Noggin knockin: Bike helmet research?
September 5, 2014 7:09 PM   Subscribe

I'm interested in solid research on the safety of bicycle helmets. I'm pro, but open to research supporting the cons.

My partner and I have an ongoing debate about the efficacy of bike helmets. He thinks they're not necessary unless riding in big-city traffic. I think they're requisite even in suburbia. He refuses to wear a helmet unless in busy big-city traffic (think downtown Manhattan) and this makes me crazy, and worried for his safety. He's a good cyclist who doesn't ride like a crazy person, ride drunk, etcetera--but nonetheless I worry about things like train tracks, distracted drivers, drunk drivers, doors, and the like. Any good research out there? I'd love to convince him to wear a helmet, but I'm open* to work that debunks the safety of helmets, too.

Thanks Mefites!

*Although admittedly doubtful
posted by stillmoving to Sports, Hobbies, & Recreation (15 answers total) 9 users marked this as a favorite
With no support for their findings intended, the Bike Helmet Safety Institute is probably the most comprehensive resource you will find.
posted by saeculorum at 7:16 PM on September 5, 2014

Best answer: Helmets are only rated for very specific types of crashes that are only a subset of the crashes that happen in real life. I personally don't wear a helmet when riding in the city. Here's a link dump of articles that helped me come to my decision:

Be cautious of people citing trauma surgeons, who only see the outcome of accidents and aren't tuned in to the big picture the way public health researchers are.

Anyways, if it makes you feel any better, he'll probably end up being much healthier and live longer as a cyclist who doesn't wear a helmet than as someone who doesn't bike. Biking is great for you regardless of your choice of headgear.
posted by no regrets, coyote at 7:22 PM on September 5, 2014 [5 favorites]

The importance of bike helmets is different from an individual perspective and a public health perspective.

The argument for individual use of a bike helmet is that it reduced the likelihood of head injury. I don't think anyone disputes this.

The argument against the mandatory use of bike helmets is that it reduces the overall amount of bicycling done by a population, and shifts transportation to cars and other unhealthy options. This has a negative consequence for overall public health that some studies have shown outweighs the positive effects of increased helmet use.

For your partner as an individual there's really only one argument against wearing a helmet, and that is that he won't ride if he has to wear one.
posted by alms at 7:27 PM on September 5, 2014 [5 favorites]

Some bike helmets are not helmets. Hovdig probably have some interesting info on their site.
posted by Kerasia at 7:49 PM on September 5, 2014

OK, so this isn't data, but a personal anecdote from a safe bicycle rider:

I was in a bike lane, going down a hill and approaching an intersection with a light. It just turned green so I figured I was good to go and kept coasting down. There was an older lady in an SUV coming the opposite direction in the left turn lane. She was waiting, I had the right of way, so I keep going. Then she decided to turn anyway, right in my path--I don't know if she didn't see me or if she thought she could make it. I braked to avoid hitting T-boning the carand yelled, but instead of gunning it through to avoid me she stopped directly in my path. Maybe she panicked? I slammed the brakes harder and it sent me over the handlebars and directly onto my head. I got mobbed by pedestrians and people in nearby houses who were amazed I was able to get up, much less walk around. No damage, not even a concussion because I was wearing a helmet (though my neck was pretty sore for a few days). By the way, that's the SECOND time I've been in a bike accident with someone making a left-hand turn who didn't see me coming. Some people do not watch for bikes, period.

Your husband can be as safe as he wants up until the point he encounters someone who is just plain bad at driving. And then he's at their mercy. Maybe if he ever complains about bad drivers you can ask him whether he'd like to be on the same road as them when he's on a bike.

So. Anecdata. But sometimes that's more compelling to people than actual data.
posted by Anonymous at 8:26 PM on September 5, 2014

I'll only point out that suburban riding is probably much more dangerous than big-city riding. Higher speeds (both bikes and cars), less lighting, and fewer bikes-- more bikes means drivers are more used to them.

For me, wearing a helmet comes down to marginal cost, marginal benefit. I would be riding (daily) either way, and it's such a small cost. Even if the benefit is a 1% smaller chance of dying in a crash, that's pretty worth it.
posted by supercres at 8:27 PM on September 5, 2014 [3 favorites]

> Anecdata. But sometimes that's more compelling to people than actual data

The OP was looking for research, not a single self-selected datapoint. The fact that it may be compelling is entirely contrary to the spirit of research.

Try Bicycle Helmets and the law: a perfect teaching case for epidemiology. – Bad Science.
posted by scruss at 8:35 PM on September 5, 2014 [7 favorites]

That BMJ link is the best thing I've read on the subject.
posted by grubby at 8:47 PM on September 5, 2014

This article brings up some good points regarding hidden downsides to bicycle helmets. This blog post goes into some of the data.
posted by exogenous at 8:52 PM on September 5, 2014

Last year Bicycling Magazine did a huge article on the history of bike helmets and how generally poorly designed they are, and how the best helmets come from Europe and why most helmets in America are lagging way behind.

Other links in this thread are good, there are studies that show in cities, cars give bikes more space when you're not wearing a helmet, because drivers consider riders more vulnerable.

I personally ride about 150 miles a week using a variety of bikes, and my general rule of thumb is to wear a helmet always, all the time, EXCEPT when I'm on my city bike riding in traffic. It's lower speed (~12mph?) than ripping down farm roads on my road bike (20mph+), it lets drivers see your vulnerability, and you can hear/see better than not having a helmet on. Also, it's just easier to ride your bike to stuff, park it, lock it, and go on about your business without having to carry a big ass helmet around.
posted by mathowie at 8:57 PM on September 5, 2014 [6 favorites]

Best answer: Prefacing by saying that I'm generally an anti-bike helmeter who almost always wears a helmet (largely to stop people from telling me to wear a helmet). I think there are better ways to keep cyclists safe than a piece of plastic on their head - separated infrastructure, especially - and that helmets are generally a band-aid approach to this and are something that is perpetuated by (and I say this partially tongue in cheek) The Helmet Lobby and (more seriously) the Driving Lobby as ways to stop those crucial infrastructure and urban planning changes from happening because it could cut into their bottom line.

I also think a lot of the perceived "need" for helmets is based around cycling style in North America, where we are still in the sport bike phase where people are going Fast! and are oriented with their head kind of parallel to the ground. But with Euro-style cycling that's coming into vogue in NA too, the bikes are much more upright and the pace a lot slower and for those helmets make less sense. If only we had their style of infrastructure...

But less anecdote and more science:

Dr. Kay Teschke - Bicycling injuries, helmets, & helmet legislation, January 2012. Prepared as expert testimony for a Provincial Traffic Court case: Regina vs. Van Der Eerden - Kay Teschke (someone linked her awesome Twitter, above) is a professor in the School of Population and Public Health at UBC. It has some good references, too.

A good Copenhagenize blog post on the subject with pertinent references.

Related to ski and snowboard helmets, but a good piece on the risk compensation hypothesis with helmet use (essentially people are shown to be more risk taking when they have greater perceived safety, such as with a seatbelt in a car or a helmet on a bicycle, but also there's an element like mathowie mentions above about drivers taking more risks around cyclists with helmets because of their perceived "safety" of the cyclist due to that piece of equipment).

And an article that talks about how there are comparable levels of head injuries suffered while driving or walking, and yet we don't think people should wear helmets for those activities. It's based on this scientific study.
posted by urbanlenny at 11:24 AM on September 6, 2014 [3 favorites]

Best answer: i've read all the articles linked here as well and i usually ride something like 80 miles a week on a mix of city streets, bike paths, and 'bike boulevards.' so i would describe myself as reasonably competent and risk-averse on a bike, but despite this, i've had a few accidents in the past couple years.

the argument commonly levied against wearing a bike helmet is this: wearing a bike helmet does not significantly reduce the risk of you getting into a bike accident.

i first heard this and i too was dubious, but it 'logically' makes sense if you swap out the words to read: wearing a seatbelt does not significantly reduce the risk of you getting into a car accident.

it's true, neither seatbelts nor bike helmets are 'crash wards' with magic powers to prevent accidents. if you look at most accidents, they're not typically caused by helmets or seat belts. and if you've been the unlucky recipient of a car crash or gotten into a bike accident, it probably didn't happen because you were (or were not) wearing a helmet. let's just say this: people rarely elect to have bike or car accidents, they are often chance occurrences.

but the reason to wear helmets (and in cars, seatbelts) is in the admittedly rare event that we have an accident that involves our head smashing into the ground, we are highly certain that our relative risk of head trauma is lower when we wear a helmet. similar to how an egg's risk of breaking when falling is lowered when it is encased in an egg carton.

the studies seem to give a pass on not wearing helmets because it acknowledges that there are lots of confounding factors to getting into an accident. we just don't know why accidents happen, very often it's road conditions or the biker or the speed of travel or 'risky behavior' or any of those things. again, a helmet is probably not the direct cause of an accident.

the bmj article says we would achieve greater benefits for bicyclists if we could minimize the causes of their accidents. in terms of scale, accidents are a greater risk factor for bicyclists than their helmet choices. it then causally mic-drops with a "risk is unintuitive and mired in politics ¯\_(ツ)_/¯"
The enduring popularity of helmets as a proposed major intervention for increased road safety may therefore lie not with their direct benefits...but more with the cultural, psychological, and political aspects of popular debate around risk.
but the risk of head trauma exists! it is (admittedly) not as great as other risks that bicyclists face (e.g. the ones you list like drunk/distracted drivers), but it's still there. and you know what, your brain is really soft!

i've never had a car-related accident (thankfully), they've mostly been due to unexpected road conditions (losing traction, fine gravel on a turn, an unexpectedly small pothole that somehow caught my wheel) or another cyclist and in each i was glad to have a helmet even when i took the fall gracefully or broke my thumb.

whenever i hear people rationally arguing against helmets, i get the impression that they've made peace with how random accidents are and that (probably) their head trauma will be the least of their worries. and that's certainly their call to make, but it often ignores that the risk of head trauma remains non-zero in all cases. accidents rarely go the way you'd like them to, and small probabilities of head trauma are hard to reason about but i suppose i prioritize my brain because i'd like the expected value of its trauma to be as small as possible. everyone is free to choose risk cutoffs that match their values and priorities and i guess it's sorta clear where i draw my line, but prob/stats concepts like 'relative risk' and 'expected value' helped me understand my choices given all the data and blog posts.
posted by nsfmc at 12:04 PM on September 6, 2014 [2 favorites] has a fairly comprehensive list of references. You might not like the fact that the authors have come to believe that the efficacy of helmets is vastly over-rated, but you can go read all the primary sources they reference if you want to and draw your own conclusions.
posted by pharm at 12:18 PM on September 6, 2014

Something I didn't address in my previous comment, but on second thought seems worth mentioning, is the social/political statement involved in wearing or not wearing a helmet.

One of the main reasons that I stopped wearing a helmet is to try to help normalize urban bicycling in a city where the general image of cyclists is as lycra-clad, helmet-wearing speed demons. This might seem like tilting at windmills but it's important to me for personal, social and environmental reasons.

Even if I was convinced of the effectiveness of bike helmets (which I'm not), I'd still be willing to give up some amount of relative risk to make that statement. It's possible your husband feels something similar in which case statistics probably aren't going to convince him otherwise and you may have to take another tact.
posted by no regrets, coyote at 3:12 PM on September 10, 2014 [1 favorite]

I saw another item come up today that calls into question the veracity of some of the earlier studies on bike helmet effectiveness that I thought you might find useful in your consideration of the issue; there are lots of good links to more information within this post:

Feds will stop hyping effectiveness of bike helmets.


In 1989, a study in Seattle estimated that helmets prevent 85% of head injuries. Later efforts to replicate those results found a weaker connection between helmets and head injuries, but public health advocates, government web sites, and the news media often present it as fact.
posted by urbanlenny at 7:59 AM on September 12, 2014

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