I don't have a formal citation, but a bit of pondering suggests it's not an unreasonable extrapolation.Chris Jeggo wrote: ↑5 Oct 2022, 5:43pmDo you happen to have a reference for that statistic, please?
We know the spec of a cycle helmet, most often EN1078, and we know it's to take a fall from stationary to hard ground with no other parties involved (that's what the testing regime simulates).
We also know, as dmrcycle pointed out, that in absorbing a full-spec load of energy it's entirely reasonable to expect a helmet to crack.
If we look around at where falls from low speed to hard ground are common then I'd suggest school playgrounds are a good candidate. Falls with head injuries are so common that the primary school my kids went to had a special protocol. If a child fell and didn't hit their head they'd get some TLC and an I've Been Brave! sticker, but if it was a head injury, those being more serious, additional measures were deployed. That meant another sticker (I Banged My Head!) and a form letter home to parents. Note that's a form letter, not a specially prepared one, and the I've Banged My Head! stickers were ordered in sheets from a catalogue, just like gold stars for workbooks. Both of those points indicate a common injury.
Now imagine that children have to wear helmets for free play (just as they often have to do for Bikeability lessons in the same playground, because the RA says they might fall or collide, just like they do in free play on a daily basis), and how now we'll see quite a number of cracked helmets as a result.
While trips and falls can kill from head injuries, they rarely do in terms of rates (you still get quite a number as so many people fall over). While they are the second highest cause of hospitalisation with head trauma (after car crashes), the fact is that the vast majority are dealt with by the body with a bit of R&R and feeling sorry for oneself. So if the number of children that start appearing with cracked play helmets start having assumptions made that they'd surely have cracked their skull and/or been killed without the helmet at the same rate helmeted cyclists seem to, everyone would be terrified to send kids out to play without head protection, but it would be confirmation bias and culture rather than an objective risk assessment.
Just like the post that started this thread, while one can safely assume that a cracked helmet has probably saved one a very nasty headache, it's a very big assumptive leap to take it as read that one would have surely ended up listed as a serious/fatal injury after a hospital visit. Yet any trip to the comments/followups of a social media post where it's suggested that helmets are a bit of a distraction can be guaranteed to cause plenty of "but a helmet saved me from terrible injury!, it was cracked!" anecdotes to come out of the woodwork.
Pete.