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Comment by watwut | Hacker News Reader

Helmet does not help in high speed crash with car and is not designed for it. It helps in small falls.

I've seen that stated many times. As far as I can tell, it traces back to a news article that did fun things like cherry picking individual observations from a study to support a claim even though the study's overall findings were contradictory.

My own sense is that the science seems pretty clear that, provided you are in a wreck, wearing a helmet greatly reduces your risk of serious injury and death. Helmets aren't perfect, and they may primarily be designed for lower-engery impacts, but even insufficient energy dissipation is better than zero energy dissipation.

There's a secondary claim that not wearing a helmet results in safer behavior than wearing one, and that outweighs any potential benefit. I'm not aware of any quality research to back that claim, and you'd never be able to get a study to pin the question down past an institutional review board, so I'm inclined to say that cuts very close to what we called a fundamentally unanswerable question back in my class on experiment design. (Well, actually we used the acronym most the time. ^_^ ) My personal sense is to think that expecting your garden variety distracted, chronically fatigued, or nonzero BAC driver to notice whether you're wearing a helmet in the first place, let alone modify their behavior accordingly, is giving them more credit than they've earned.

> provided you are in a wreck, wearing a helmet greatly reduces your risk of serious injury and death

So . . . you wear a helmet when driving? Because people get head injuries all the time in car wrecks.

My bicycle doesn't have nearly as many air bags as a typical car.

You're right, though. Cars are fundamentally dangerous. High risk of violent injury or death, and, even in the best case, they subtly harm your health and longevity by encouraging a sedentary lifestyle. Damned expensive, too. Perhaps we should all just move to Rotterdam so we wouldn't have to deal with them so much.

https://hovding.com/ - bicycle airbag.

> My bicycle doesn't have nearly as many air bags as a typical car.

yet statistically per-passenger-mile you're more likely to get a head injury while in a car than on a bike.

On a motorcycle, yes. Otherwise, I'm surrounded by a cage of metal.

It's really not an unreasonable point. As a society, we make rules all the time about safety )that may or may not be rooted in actual statistics). I certainly did lots of things as a kid that would be seen by at least many people I know as reckless today in terms of safety equipment.

An argument can be made that you should wear a helmet of some sort in many circumstances where it's not required (or expected) today. Look at downhill skiing. It's still far from universal but no one (besides racers) wore a helmet until 20 years ago or so. I still don't wear one.

The same could be said for pedestrians (slipping on ice, getting hit by a car).

> I've seen that stated many times

Including on bike helmet safety labels. Fact is, they really are designed for falls and not for collisions with motor vehicles. In that situation, they may just be a "better than nothing", possibly not enough to make any difference to the outcome.

Assuming you are landing on a horizontal surface, it's only the vertical component of the fall that you have to worry about. A fall from 2 meters accelerates you to about 22 km/h (27 km/h for 3 meters). Helmets are design to protect you from a 2-3 meter fall onto an anvil (depending on the standard). As long as you don't hit anything vertical (the curb, a telephone pole, a car, etc), a helmet will give you good head protection no matter how fast you are going (and will also give you some protection against abrasions).

Depending on how fast you are going, a helmet may even help for hitting things. Quite a few people don't exceed 25 km/h on their bikes, especially in city situations. Similarly, if you are aware of a dangerous situation, then slowing down may give you some protection. It's absolutely not going to help if you are bombing along at 40 km/h and get doored, but at that point, nothing really will.

> It's absolutely not going to help if you are bombing along at 40 km/h and get doored, but at that point, nothing really will.

One thing that would help is taking the lane when going at those speeds. People don't normally drive their cars going 40 km/h in the door zone, so the same thing should apply when riding a bicycle.

> I've seen that stated many times.

The Consumer Products Safety Commission (CPSC) impact testing procedure for bicycle helmets does not account for collisions with motor vehicles [1]

[1] https://www.law.cornell.edu/cfr/text/16/1203.17

Absolutely not true. Concussions are always a threat, and a helmet provides limited protection even in a high speed collision.

From experience I came off in London at slow speed an definitely had concussion that night.

I still managed to walk to train station with the bike which had a puncture - only in the morning when I got up did I notice I had dried blood all down one side of my head

Helmets have limited ability to prevent concussion. What they do help prevent is cracking your skull or scraping your scalp off.

Consumer Reports does excellent research, I recently discovered, not only their own original research on products but they provide the background literature too:

https://www.consumerreports.org/head-injuries/wear-a-helmet-...

The majority of serious injuries from cycling have one thing in common, says Fred Rivara, M.D., M.P.H., a professor of pediatrics at the University of Washington. “Two thirds of hospitalizations and three quarters of deaths from bicycle injuries are due to head injuries,” he says. “The most effective way to prevent that from occurring is to wear a helmet.”

Indeed, extensive research has demonstrated that a helmet is the best way[0] riders can protect themselves against head injuries—especially those that are potentially fatal.[1]

https://www.consumerreports.org/cro/bike-helmets/buying-guid...

Statistics bear it out: According to the Insurance Institute for Highway Safety, in the majority of bicyclist deaths the most serious injuries are to the head, highlighting the importance of wearing a bicycle helmet. Helmet use has been estimated to reduce the odds of head injury by 50 percent and the odds of head, face, or neck injury by 33 percent.

Tangentially, here's how they test bike helmets:

In our tests we strap helmets onto head forms and use an apparatus that drops the helmets at about 14 mph onto a flat anvil to find out how well they withstand impact. An electronic sensor inside the head form monitors the force that would be transmitted to a rider’s skull in an accident.

We also test the strength of helmet chinstraps, attachment points, and buckles. We drop an 8 3⁄4-pound weight 2 feet so that it yanks on the straps to simulate the force that might occur in a crash.

EDIT: Add a paragraph and footnotes

[0] http://www.cochrane.org/CD001855/INJ_wearing-a-helmet-dramat...

[1] https://www.ncbi.nlm.nih.gov/pubmed/27450862

I generally agree, but I want to point out that there is a huge range of impact protection depending on the general shape (e.g. 'aero' vs 'skater' style), construction (hard shell downhill MTB helmet vs typical road helmet) and fit. I can't count the number of times I've seen a cyclist with a terribly ill-fitting, poorly positioned helmet. I've seen many completely exposed foreheads, thanks to too much rearward tilt, and mostly exposed skull bases thanks to the impractical aero/race-inspired design that's dominated the road market for decades.

I know about fit and positioning, but I haven't heard there are differences in safety due to shape or the "aero/race-inspired design". Where can I find out more about it? Has any research been done?

Personally, though I ride a road bike, I wear a fairly standard MTB helmet. Really, I like the visor more than anything, but I do think it has better protection all-around.

I also use MTB (Shimano SPD) pedals: they're easy to clip in and out of, and I can wear normal-looking shoes that I can actually walk normally in.

The racing stuff is just ridiculous: it gets you a tiny improvement in performance at a huge penalty in usefulness. If you're not actually racing, it's pointless.

Some "racing" bike helmets are wonderful though - they block minimal airflow and are very lightweight, so you don't even notice wearing them.

Yeah, but surely that comes at a cost, of less protection for certain types of falls. See the parent's comment about mostly-exposed skull bases for instance. Personally, I'd rather have better protection even if that means a little less airflow and a few grams more mass. (Of course, you can go to an extreme here; those full-face MTB racing helmets are really too much IMO.)

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