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Old 08-14-14, 03:32 PM
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I do have apologize about one thing: I've overstated the amount of energy a current helmet can take. I said 150, but it's actually more like half that. Eg

Helmet standards and capabilities
In a recent Court case, a respected materials specialist argued that a cyclist who was brain injured from what was essentially a fall from their cycle, without any real forward momentum, would not have had their injuries reduced or prevented by a cycle helmet. This event involved contact against a flat tarmac surface with an impact energy potential of no more than 75 joules (his estimate, with which I was in full agreement). The court found in favour of his argument. So a High Court has decided that cycle helmets do not prevent injury even when falling from a cycle onto a flat surface, with little forward momentum. Cycle helmets will almost always perform much better against a flat surface than any other.

..In theory, a helmet should take up to about 100J. To give an idea of how little this is, a Snickers bar contains about 1,000,000J.
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