What made you go WTF today?

[oldmunchkin]

Can I take it your opinion is based on looking at relevant scientific evidence?

I know you don't like any answer that isn't backed up by 4 or 5 links of science. Any answer that isn't backed up is therefore is wrong! So, my answer that is only backed up by years of experience on said subject must be bullshit!

Inside a car, you don't brake with your head!

You wear seat belts in a car, because then you are "fixed" to this car. Which means that if the car brakes, you will decelerate at the same rate. With the crumple zone available (about 1 meter) this means that the deceleration just was reduced to a mere 30g (@~90Km/h) - while that will break bones, you also will survive that.
If you don't wear a seat belt, you will be catapulted out of your seat and usually through the windshield. Which obviously is a bit more problematic to your health.

It's the same principle with a helmet - I can calculate the g-forces you're subjected to with and without a helmet. You'll see that even a mere few centimeters will make a difference between "bashed-in brain" and "evil headache".

This is physics.

Fine, I'm too stupid to understand physics! Whatever!

Okay, some small calculations to bring my point across.
Let's take a car travelling at 90 Km/h, that's 25 m/s. Let's have that car have a crumple zone of 1 meter or an equivalent thereof. Which means that you go from 90 Km/h to 0 Km/h over the length of 1 meter.

For that, I'll need two formulas: v = a * t and s = a/2 * t^2
v = velocity (90 Km/h or 25 m/s), s = length (1 m), t = time (unknown), a = deceleration (unknown).

Rearranging them yields:
s = a/2 * (v/a)^2 <=> a = 0.5 * v^2/s

Using the values listed above, we arrive at a deceleration of a = 312.5 m/s^2 which is about 32 times the gravitational acceleration or 32 "gees". That is indeed survivable. Broken bones, surely, but survivable.

Let's assume now that you did not wear your seat belt, thus being catapulted out of it, resulting in a deceleration a the windshield. For shits'n'giggles, let's also assume that the windshield is unbreakable. You now have a deceleration length of mere centimeters, i.e. your skin. Let's be generous and make that 3 centimeters total.

This results in: a = 10416 m/s^2. Which is about 1061 g. Okay, that would be rather deadly. Thankfully, the windshield is not unbreakable.
------------------------------------------------------
Same stuff for riding a bike. Let's assume you managed to brake somewhat and were hurled over. Thus arriving with your head on the street at, say, 20 Km/h.
With your helmet, you have a deceleration equivalent length of, say, 6 centimeters.
This gives us: a = 252m/s^2 or 26 g

Without a helmet, we use the 3 centimeters again and arrive at a whoppin' 52 gees.

And I'm pretty sure that those 3 centimeters are very generous.

Once again, you guys win! Your fucking physics is always the only thing this should be based on! Once again, plain old practical experience, and common sense, loses!

Everyone knows that the government's only job should be to give poor people money and set up free health clinics in rural areas; otherwise, the government should butt out of their affairs.

Oh horseshit! If the government paid as much attention to the important things happening, like solving the budget crisis, getting out troops out of war-zones, solving unemployment, and making sure the poor had the same access to the same medical care the rich have, as they do to wasting time infringing on privacy issues and personal choices, this country would be financially fit, all our troops would be home, there would be no unemployment, and the poor would have the ability to see a doctor when they are sick!

Unfortunately for me, I am the one with the friend who is a quadriplegic from her neck snapping while riding her bike. She was gently rear-ended by a car, causing whiplash, or at least that would be all she had if she had not been wearing a helmet! And, before you talk about her not paying attention to the traffic around her, it was a completely unavoidable (on her part anyway) accident! And don't say she should have heard the car coming, because the helmet muffled the sound to the point she had no idea there was a car there! For some reason, logic tells me she can't be the only person to have an accident like this one!

Or the person who is in a vegetative state from a head injury incurred when he went over the handlebars of his bike! If he hadn't had a helmet on, he would have simply died, instead of being a vegetable the rest of his life! Who knows what kinds of medical bills have been racked up, paid for by the taxpayer after his insurance ran out. Hmmm, I think I'd prefer to be dead than a drooling, blithering eggplant the rest of my life. If nothing else, it would have spared his family the torture of seeing him in this state!

Or how about me? Every car I have gotten into and fastened my seat belt for the ride, is a car ride that might be my last! At my size, there is NO seat belt/shoulder strap that doesn't cut right across my neck! If I am in an accident, there goes my head! And don't tell me to adjust the fucking things...I have them adjusted for the shortest person possible, and they still cut across my neck! I can either use a fucking booster seat for a child, or be smart and not wear something that is sure to decapitate me!

Just because you don't agree with me, or are just too stubborn to see anything from any point of view except yours (or the government's) does not mean I am wrong!

[Khendraja'aro]

Once again, you guys win! Your fucking physics is always the only thing this should be based on! Once again, plain old practical experience, and common sense, loses!

My dear moron, all physics is based on practical experience. Save for the most remote boundary areas of physics (i.e. String theory and such), EVERYTHING is based on practical experiments.

Do you really think that those formulas I posted up there came about in the void? If so, you're a daft old bat which really doesn't have a fucking clue.

[BalticSailor]

I know you don't like any answer that isn't backed up by 4 or 5 links of science. Any answer that isn't backed up is therefore is wrong! So, my answer that is only backed up by years of experience on said subject must be bullshit!

Fine, I'm too stupid to understand physics! Whatever!

Once again, you guys win! Your fucking physics is always the only thing this should be based on! Once again, plain old practical experience, and common sense, loses!

As illustrated by the article that started off this discussion, common sense is a lot less common than the name suggests...

And yes, this should be based on physics - for the simple reason that, as far as everyday life is concerned, laws of physics are universal, reasonably well-defined and unchangeable. They don't care for your personal experience. Acceleration won't be different for you just because you don't understand it. Gravity will not treat you differently than any other person just because you think you know better what's right and what's wrong. Laws of physics don't have any emotions, feelings or prejudices, and they can't be reasoned with or persuaded to change the way they work.
Laws of physics in these situations are absolutely free of subjectivity. And basing safety regulations on anything less objective would be foolish at best.