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This was the moment when a simple explanation ended the thread. But you like to dig over-analytical holes when none is needed. This is what happens when you get too much into data that it just becomes something to prove a point across no matter what.

For snowboard you want a helmet with no holes, and ear protection, even when hot, snow will get in ears and is a pain, also snow melts so if it gets in holes it makes your helmet wet inside. Nice to have is a short one inch front ledge, if you are landing on your face that bit will hit the ground before your nose, I purposely turn my head into the fall to make it happen. Better a hit in the higher part of the face and helmet than landing jaw or nose first, is as bad as it sounds. It needs to be shaped in a way that doesn’t impede your goggles, no sun shader so you have a better field of view upward, in some jump tricks you need to look upward. Need to stop hits on ice at high speed and slide, smoother helmet surface is better. Hits come from any direction, including the rear of the neck, so the helmet cover the sides and the rear a lot. Finally it’s likely to be fitted with a plastic clip in the back to retain your goggles strap so when you hit hard goggles don’t fly away.

For bicicle you want a lot of holes to cool you down, nothing blocking your ears cause that’s where your sunglasses sticks go. Sticks go outside the helmet lace cause it harms less if you fall. Need big long sun shade so the sun won’t cause reflections on your sunglasses, you will not need to look upward aniway. But left-right it need a to give a good field of view. Need to stop car hits for life saving purposes, no need to protect the face as yo are not looking for continuous hits. Instead, it’s focused for the centerline hits, front, top, upper rear. Its way deeper in protection compared to a snowboard one.

For downhill bikes you want a full face helmet because tooth and face surgery is expensive. It needs to stop the big hits but also prevent the continuous face scratching done by tree branches, and light hits to the ground in light falls. It is generally designed to be connected to neck protection too.

To close it: street bike helmets can be one shot, you hit, you discard the helmet. This allows lighter and softer designs, and a in depth protection; that single hit will hurt less that in a reusable helmet. Most extreme sport helmets can retain shape after multiple light hits. If I had to replace the snow helmet every hit, I would be broke. This comes at the cost of the helmet being a bit more rigid, giving less comfortable, sharper hit feeling, and more weight.

I get the point, however, I live in Denmark where 60% rides their bike to work, and most of them are easily going 20-25 mph, so it just doesn't make sense for me

Ski helmets are also generally meant to take a lot of smaller hits, bike helmets take 1 big one and are meant to be replaced.

Any source for actual difference in offered protection design? (There are helmets approved for both, given that the actual test requirements for the head protection are nearly identical. To project with the impact from about head-height to the solid ground below. That is, a fall.)

The cooling of the head, or keeping it warm, is the obvious difference in design. Most bike helmets are perforated nearly to oblivion resulting in very lightweight helmets. The helmets that suit both for both are too warm for sportive cycling, work decently for leisurely commuting with an upright bicycle, and excel as a winter helmet for such cycling.

Any sources for the different protection design? (I have a strong impression that both bicycling and skiing helmets are designed and tested for a very similar crash. An impact of the head with the ground, with a velocity corresponding to a fall from about head-height of a tall person. There are also helmets that are rated for both activities, but which only suit leisurely cycling for the reason underlined below. They are, however, excellent for winter cycling at a slow or a moderate pace.)

The main difference is in the need for cooling (a bicycle helmet needs to keep your head cool whilst exercising). The skiing helmet needs to keep your head warm against the windchill of going fast in the colder winter weather.

I have also a very strong impression that no bicycle helmet is designed in particular for an impact with a motor vehicle. The required test is to protect against the head hitting the solid ground from the height of an person cycling.

First, we can note that both types helmets have essentially identical requirements for attenuating impacts (and nearly identical tests to validate their performance on crashes). So, there is no crash-safety reason for the difference. (Like, a bike helmet is not particularly designed to protect against an impact with a car.)

Thus, the main reason is due to different needs for ability to cool of ones head. A person driving a bicycle needs much better cooling (two reasons: typically warmer weather and the act of cycling itself). Thus, a bike helmet has plenty of cooling holes. The skiing helmet does not need these, thus, one can use a shell with far less ventilation (resulting in a helmet that is a bit more robust against wear and tear, in addition to a nice smoother look of helmet).

There are, however, helmets that can be used for both; and which are sold for both. These are clearly in between the fully smooth skiing helmet and the highly perforated bicycling helmet. A few holes, sometimes with adjustments. (Though, given the limited maximum ventilation, such helmets only suit leisurely cycling. A such, they are also excellent for winter cycling, especially if done at leisurely pace, say, to commute at a pace where one does not need to shower or even change clothes at destination.)

They're designed to protect against different injuries more common to each of the activities.

Bike helmets are generally designed to protect against low-speed blunt collisions (I've read about 4m/s), such as falling off your bike and hitting your head on the ground, or a small inclined object like a curb. They're also designed so that if you do hit your head your spine won't rotate, which can cause very serious injury or even instant death.

I know less about ski helmets, but they have to protect against higher-speed collisions with upright stationary objects (such as trees), and they also protect the user's face and eyes from cold weather while maintaining visibility, which bike helmets don't have to do.

Your topic reads like the opposite.

I'm probably not going to be able to express it well, and indeed might even say it very badly. I'll try, though. The U.S. government has one purpose. To keep the states united so they don't start going to war against each other. So there have to be standard laws that apply across all of the states, and laws that apply only in certain states must not violate those laws. Now just replace the word "laws" with "taxes". Sort of, anyway. The taxes that we pay go towards being able to pay the national debt.

Now, this is going to sound ridiculous as I don't know how to say it, but the idea here is that companies don't want to pay taxes, so they try to own government officials to have those people stop rulings that will make them pay taxes. So the folks who want the government to have more authority mean to make those companies pay the tax they should owe.

Here's the way I understand it. People want the govt to tell businesses what to do. Businesses want to make as much money as possible and limit competition. So the businesses intrench themselves with politicians and govt. Thus the businesses can control the government to get what they want. So in theory if you give the government more power while they are being controlled by business. You are actually giving big business more control.

You basically have to find a way to keep money out of politics. In the US we don't have that. Money is heavily intrenched in politics. Every politician is bought.

Plus when regulations are being proposed for an industry only the big players are invited. Thus the big players can make regulations that squeeze out the little guy.

Mountain biking. is typically done when the weather is warm so you wouldn’t want to wear a ski helmet because ski helmets have a lot of built in insulation.

Thank you for all the answers!

They just think of corporations as a mean brother that bullies them and want government i.e. daddy to babysit them instead without realizing that dad is also an abusive alcoholic.

Because corporations have a singular and sole objective which is "to make as much money as possible". That's it. That's their only purpose. This is doubly true for publicly traded companies who are obligated to their stock holders who only want their stock price up.

Privately held businesses might operate on the ethical standards of their owner but large corporations have very little practical, financial, or functional reasons to be good employers. They have every practical reason to be profitable businesses.

Which means, in the absence of some power telling them not to they will do anything and everything they can to increase profits. Google the Triangle Shirt Waste Factory fire for a good example of this.

So the functional idea is that if you value people then companies need to be told to NOT do things like..wage collude to keep wages artificially low, or skimp on safety measures, or hide money from taxes or, I dunno, avoid safety precautions on your trains carrying tons of toxic chemicals because it's cheaper, and who cares if some kids in a small town in Ohio get birth defects?

Some people care more that a bunch of women don't die horrifically in a factory fire, or children don't end up with cancer because a train spilled vinyl chloride in the town's water supply, than they do about a company making an extra billion

Very few people believe that corporations have absolute control of the government. Those who do tend to oppose anything and everything related to the government.

Moat people believe that corporations currently have too much power over the government. They would like to see this reversed, with the government limiting the corporations instead.

While the idea of "expanding social safety nets" and such iterations are a different (but valid) topic, I'm more curious about the people who dislike corporations, and for that specific reason, want to expand the government to control the corporations.

..wut?

Most people who are of the left wing liberal persuasion of "expand social safety nets, expand job and wage protection, expand safety regulations, expand protections for marginalized communities" are also the same people who want to get corporate money out of politics because it is those corporations who spend millions of dollars lobbying the government to not do those things because it's more profitable if the government doesn't.

People who believe that the government should be more protective of human interests are generally the same people who think the government should be less protective of corporate interests, so inherent in the idea of "expand the government" is "stop making government beholden to corporate interests that are trying to keep the government's expansion in check in order to make more money"

I wear a helmet for two reasons:

I don’t always see low hanging tree branches

If I am injured or killed by being struck by someone driving a car, I don’t want the damages to me or my family reduced because I wasn’t wearing a helmet.

That’s also the reason why I don’t run stop signs or red lights.

The card has a circuit with an antenna and small programmable chip with a unique identifier but no battery. The reader is actually just a big RF antenna, when you bring the card near enough to the reader the circuit is powered by that RF energy (similar to how wireless charging on a phone works for ease of explanation) enough to produce a small return signal. That return signal contains your unique identifier and is picked up by the reader which then communicates over the network or internet to a server. The server checks if you have access to that door and if you are within your allowable access schedule, and triggers a magnetic solenoid that releases the catch on the door allowing you to open it.

The card contains a tiny antenna and chip. The scanner emits a field that both communicates with the chip in your card as well as provides it power, similar to how a wireless phone charger works.

The chip contains a code that is linked to you in the school's student database. The scanner will check with the database to make sure you are allowed in that location. It may also log what time you scanned your badge and where.

It has a tiny electronic chip inside, and a coil made from very thin copper wire. The readers emit a high frequency magnetic field which induces enough power in the coil to turn on the chip. The chip and reader then communicate briefly, and the backend computer system can read the card ID, see that it's linked to you, and which privileges you have.

Edit: it's called NFC, for near-field communication. You can Google it to learn more.

You can probably see the circuitry if you hold the card up to a very strong light source, such as the lens of a projector.

Plus ski helmets with airflow vents usually have a way to close them with a little sliding switch, so you can get more airflow on a warm day but cut it off on a colder day.

Also... airflow and aerodynamic drag is a priority in helmet design for amateur and competitive road cyclists.

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