50sbiker wrote: ↑26 Jun 2021, 10:30am
Go scrape your forehead along the road...With and without helmet...Then tell me it makes no difference wearing a helmet.
Great advert for cycling gloves, because all you're trying to protect against is minor scrapes.
I know people who have smashed their entire face in whilst wearing a lid (and they would likely have been much less badly injured if they hadn't been, since it wouldn't have twisted their face into the corner of the car by catching on the roof rail). I have come off my bike a number of times over the years, and the only times I've ever hit a lid were on the garage door.
Neither of those are more than anecdote, but common sense is built on anecdotes, not science. The common sense tells me that my brain knows exactly how big my head is, and is very well designed/adapted to protect the head at that size and mass.
Science tells me that we have survived for many many generations without cycle helmets, even though our travelling speed was much the same (a decent runner, as would all our ancestors have been, can run a 5 minute mile - i.e. sustain 12mph for an hour).
Science tells me that the spec for a lid is based on an impact with a flat surface at 12mph - and no account is made of rotational behaviour (unlike specifications for motorcycle helmets).
Science tells me that a disembodied head (for that is how lids are tested) will hit the ground at just over 13 mph (assuming it falls 1.8m at 9.8m/s^2).
i.e. lids are only designed to protect against a simple fall, one that may result in a big bruise, even a few cuts. They aren't designed to protect against potentially brain injuring collisions, and may even make them worse by converting linear acceleration into rotational acceleration (which the brain, cocooned in its strong bone shell and fluid bath, is much less well able to tolerate).
Social sciences tells us that even the promotion of lids as a safety measure drastically reduces the number of people willing to cycle, but we know that cycling has massive health benefits, outweighing any risk several times over.
We know that walking and cycling result in about the same number of fatalities as each other per mile travelled - yet no-one seems keen on walking helmets.
We know that alcohol consumption massively increases the risk of head injury - yet no-one seems keen on drinking helmets.
NICE statistics show:
https://www.nice.org.uk/guidance/qs74/documents/head-injury-briefing-paper2 wrote:Each year, 1.4 million people attend emergency departments in England and Wales with a recent head injury. Between 33% and 50% of these are children aged under 15 years. Annually, about 200,000 people are admitted to hospital with head injury. Of these, one-fifth have features suggesting skull fracture or have evidence of brain damage. The incidence of death from head injury is low, with as few as 0.2% of all patients attending emergency departments with a head injury dying as a result.
Note that head injury here explicitly excludes face/jaw injuries as convention.
There are only ~4000 cyclists seriously injured each year, and not all of those will be head injuries (I'd say a broken leg is serious for example).
Since it is certain that not all serious injuries are head injuries, and it is also pretty certain that the most serious head injuries will be accompanied by other injuries (how often do we read that a London cyclist was crushed by an HGV, but "they weren't wearing a helmet" - as if that would have done anything at all to change the outcome - I'm going to take a stab in the dark and say that 50% of serious injuries are primarily head injury (I suspect that is a massive over estimate).
Any thought that is put into protecting against head injuries should really be focussed elsewhere - at best you're going to slightly affect 1% of head injuries.
In terms of health interventions - getting people on bikes is far more valuable than any effect that lids could possibly bring.
If we spent half the effort that goes into promoting the least effect possible method of preventing injuries (PPE is always a last resort), on actually making safer cycling routes, legislation that supported active transport, and education on the concept of a public highway then we would make far more difference than plastic ever could.