It's a matter of risk assessment. The chance of a healthy adult cycling in the Netherlands getting a head injury that would have been prevent by a helmet are so incredibly low, that making it a requirement would have a detrimental effect on the collective health of Dutch society due to slightly lower uptake in cycling.

For elderly and young children a helmet may make sense, due to the significantly higher risk of such injuries (due to reduced physical responses and inexperience). And for racing bicycles wearing a helmet is the norm.

A helmet can significantly reduce the impact of a fall, but the risk of that fall is so low that the measure becomes statistically meaningless. It is akin to always wearing a hard hat when you leave your home, because it would save you from serious brain injury if a brick fell on your head. Of course, bricks don't generally fall out of the sky, but you can never be too sure…

This doesn't mean that all safety measures are nonsense — having working lights and functioning brakes do reduce the chances of accidents. It is also tempting to compare the helmet to seatbelts in a car, but there the chance of needing them is simply much higher.

One well-researched source on the negative effects of bicycle helmets if made mandatory in the Netherlands (in Dutch): https://www.fietsersbond.nl/nieuws/fietshelmen-en-veiligheid...

A lot of people get really dogmatic about safety gear in very specific ways.

I'm willing to bet that a lot of the same people who think that not wearing a bike helmet (and especially allowing a child not to wear one) should be a criminal offense would think the idea of having to wear a helmet driving is just silly.

The attitudes around helmets for downhill skiing have gone through a similar shift. It used to be that essentially no one except racers (and then snowboarders) wore helmets. Now, at least some people will chastise you if you don't.

And it's not just a US thing. Copenhagen and Amsterdam are both big bicycling cities but a fair number of people in Copenhagen do wear helmets and you don't see nearly as many of the bare headed young kids perched on top of the handlebars that you see in Amsterdam.

> I'm willing to bet that a lot of the same people who think that not wearing a bike helmet (and especially allowing a child not to wear one) should be a criminal offense would think the idea of having to wear a helmet driving is just silly.

Although I don't think biking without a helmet should be a criminal offense for adults, I think the comparison with cars isn't quite right. We do require people to use safety equipment like seatbelts and airbags when riding in a car. A helmet probably won't do much for you in a car crash but can if you wreck your bicycle just like a seatbelt would be silly on a bike.

I'm curious why you think a helmet wouldn't do much in a car crash, seeing as in any car race every driver is wearing a helmet.

I was talking about the kind of helmets bicyclists wear. The only thing a bicycle helmet would save you from in a car wreck is hitting your head against the windshield/dash which is what we have airbags and seatbelts for.

Also, race cars aren't really comparable to normal driving situations since they go much faster and have a different set of constraints than normal cars. The racing helmets, rollcages, and 5 point harnesses aren't really as necessary at 70mph as they are at 200mph

> In 2013, 50,000 people suffered fatal brain injuries; 19 percent of those were due to car crashes. Among persons aged 5 to 24, motor vehicle crashes were the leading cause of death from fatal TBI (Traumatic brain injury). It’s likely that a good proportion of the 9,500 people might have been saved had they been wearing a helmet in the car.

https://www.treehugger.com/cars/why-all-cars-should-be-hi-vi...

https://www.cdc.gov/traumaticbraininjury/get_the_facts.html

The data disagree with you.

Your first link has zero information to support that wearing a bicycle helmet would do any good, it only suggests it. Personally I doubt a bicycle helmet would do much good because they aren't designed to protect your head in such an energetic collusion. Your second link only says that motor vehicle wrecks are the cause of 20% of TBI related hospitalization. The word helmet doesn't appear in it at all.

So no, based off of your links I wouldn't say the data disagrees with me.

I think the terrain may play a part in it. As far as I know, the Netherlands is generally flat, where I live it's nothing but hills, people tend to wear helmets here, it's also the law, though I've never heard of it really being enforced. I've personally had a couple good falls going down hill where my helmet saved my head.

It's a combination of terrain and high quality bicycle infrastructure. There are plenty of countries were even I as a Dutchman wouldn't cycle without a helmet.

> The chance of a healthy adult cycling in the Netherlands getting a head injury that would have been prevent by a helmet are so incredibly low, that making it a requirement would have a detrimental effect on the collective health of Dutch society due to slightly lower uptake in cycling.

That's an easy thing to assert and a difficult thing to prove. I just assume the rules are the way they are because the Netherlands is a democracy and they want things that way, not because they're especially great at risk assessment (what population of people really is?).

I gather this is still a rather active topic of discussion and research in the Netherlands?

https://www.dutchnews.nl/news/2019/03/top-hat-bike-helmets-w...

Not a particularly active topic.

Combining your two sources suggests that making helmets mandatory would have a large negative effect on public health. (the downtick in injuries would be overshadowed by the reduction in biking)

I only offered one source, and the research it quotes suggests no such thing, so your comment seems a bit odd. The closest it comes to saying what you suggest, is not very close at all:

But a spokesman for the SWOV acknowledged that the protective head wear might be a hard sell in the Netherlands. ‘Helmets aren’t often worn in the Netherlands and we are aware of the arguments [that cycling could decrease if they were obligatory],’ he said.

I'm not invested in what happens in the Netherlands at all, but I wonder if a lot of people are just taking "the downtick in injuries would be overshadowed by the reduction in biking" for granted.

In almost every other context in which risk of physical harm comes up the overwhelmingly dominant opinion is that forgoing any means of reducing that risk is a non-starter more or less regardless of cost. Anyone suggesting that risk and cost/benefit need to be assessed is received about as well as someone proclaiming god doesn't exist in the middle of a church circa 1500.

As a safety heretic I fully agree with you that people can make their own decisions on helmet use but why should cycling get special treatment here? On every other issue of physical safety the HN gods have ruled the other way.

And yet, drivers and passengers of automobiles are not required to wear racing helmets, or five-point safety belts - nor are all cars factory-equipped with breathalyzer ignition interlocks - or speed governors which limit a vehicle's sustained maximum speed to 63 mph.

This single thing, breathalyzer interlocks, probably would save a huge portion of the lives that would be saved by fully autonomous driving, but for a fraction of the cost, and basically right now. It could even be installed on existing cars, and probably insurance companies would help you cover the cost.

Such sanity simply doesn't exist in the over-protective culture of the USA.

There are no US states that require adults to wear bike helmets, though there are a dozen or so local laws that do[1]. So 'casual' cycling without a helmet should be an option for nearly anyone in the US.

1: https://helmets.org/mandator.htm

In Texas even motorcyclists dont require helmets by law (insanity IMHO).