Sussex Police tell us we should be wearing helmets – shouldn’t they be staying out of this?

Still in two minds about

Still in two minds about helmet use. Been using a cotton cap all week as I just sort of felt like it but this weekend I’m off on a climbing route and I’ll probably hit 50 on the downhills so I guess I’ll put the helmet on. 

My mate has spent two weeks in a coma after a helmetless accident but he still won’t wear one so I guess once you’ve really made your mind up there’s no changing. 

don simon wrote:

A couple of plod were seen riding around that there Liverpool (0-3 Real Madrid) today without helmets and conspicuously all in black with no hi-viz. You’d think that they’d take note of their own advice.

Probably incognito, hadn’t filled out their whereabouts forms for UCI (a la Chicken Rasmussen)

hawkinspeter wrote:

 

By the way, I meant “naive” as in the mother’s views – I think most people on this forum have read at least some discussions of helmet efficacy.

A problem with using a destroyed helmet as a signature of a high level of protection, is that it leads to the paradox whereby the weaker the helmet, the more often it is judged to have provided protection.

My view on bike helmets is that they are good at protecting against scrapes and possibly minor skull fractures, but next to useless in preventing brain damage due to the brain ‘sloshing’ against the inside of the skull. Combined with the data that shows drivers give less space to helmet wearing riders, and I think that their net benefit is negligible.

 

Very fair point on ‘the weaker the helmet…’, except one assumes most helmets being worn have passed the relevant safety standards, and so from that standpoint most destructive hits have had some fair degree of force behind them.

I have to disagree with you on the brain damage issue, because it is the rate of acceleration (negative or positive) that is of prime importance in that instance, and if you consider under the same impact loading, if a head hits the ground unprotected there is say +/- 3mm of combined cushioning of skin and skull deformation at the point of impact and for arguments sake lets say that results in a 150g deceleration, if there is under the same scenario a combined cushioning of 12mm resulting from polystyrene deformation (whether or not it ruptures) then that drops the deceleration to under 40g, which is orders of magnitude less dangerous for the brain. 

I think, possibly contrary to many on this forum, that for your average around town cyclist helmets do little to improve their safety and would agree with you on your limited net benefit. For chidren with their combined poorer judgement and more susceptible brains etc, I suspect they provide quite some benefit, even in the accumulated non-destructive knocks which (a la rugby, boxing et al) can aggregate brain damage. For me as a racer who, when I hit I tend to hit with some force, I think they can be a ‘life saver’. I am fairly sure that compulsory helmet wearing has a negative health effect on the total population but makes negligible difference to the individual cyclist. I’m fairly certain that individual choice to wear a helmet in quite a number of cases helps prevent major injuries and on that basis confers a helath or safety advantage to the individual cyclist.

PRSboy wrote:

hawkinspeter wrote:

Combined with the data that shows drivers give less space to helmet wearing riders, and I think that their net benefit is negligible.

 

 

Interesting one that…

I am also convinced that drivers seem more patient/safe around me when I am giving it some welly rather than pottering about on the tops.  Anyone else noticed this, or the opposite?

Definitely. The slower I go, the more close passes, beeps and rants I get. Doesn’t even matter if the reason I am going slower is that I am with the kids.

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

wknight wrote:

The one key statistic we are missing is how many people saved a trip to The hospital or even calling an ambulance because the helmet saved them. 

 

I witnessed two crashes very recently where the person walked away, but their helmet was a complete shattered mess. That would have been their head and yes it is personal choice, but no one complains about wearing a seat belt. Please don’t say there is data, because the data we need re Helmets has not been gathered. Go visit a&e and see head injuries. 

If the police get involved why not, remember it’s them who have all the paperwork, investigation and having to give the family the bad news

If a bike helmet is a “complete shattered mess”, it means that the energy involved was much greater than the helmet was designed to protect against. The main protection from a bike helmet comes from compressing the expanded polystyrene inside it, not from the thin plastic outer that holds it together, so if the helmet shatters, it means it’s not doing its job correctly and most likely provided only very minimal protection.

Real life impacts are very complicated actions, and it’s entirely possible that the inital ‘killing’ impact deformed the helmet and protected the wearer, but also ruined the integrity of the helmet such that subsequent smaller impacts destroyed the now substantially weakened helmet, but those impacts were not capable of doing serious damage to the encased skull. So, a destroyed helmet does not mean either that it was subject to impacts outside it’s design envelope, nor that it offered skant protection. Just because an air bag is a torn bloody, muddy floppy mess and the vehicle didn’t stop when it deployed doesn’t mean that the air bag offered no protection at the time of impact. 

I get your point, but does that mean you support the opposite view, that if a helmet is destroyed it means that it provided a high level of protection? That’s what I was arguing against.

If a helmet is destroyed, as I pointed out, it may have provided a high level of protection, but  for sure there will be instances where the helmet provided negligible protection and was destroyed. I think these may be the minority of cases where the rider survived though. To me it’s hard to envisage an impact destructive enough to destroy a helmet that wouldn’t have had fairly devastating effects on the head contained within  had it not been there, which is really what saying ‘it provided negligible protection’ means

The site linked through http://road.cc/content/feature/241993-when-should-i-replace-my-bike-helmet – https://helmets.org/ – seems to reckon that you should replace a bike helmet when there’s pretty much the slightest scratch/dent/fading.  The helmet currently sitting on top of my wardrobe at home has lots of scratches, all of which are from poorly trimmed shrubbery on my local cycle route, none from actual falling off or collisions…  Does this mean that the helmet is now ready to go to landfill?

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

wknight wrote:

The one key statistic we are missing is how many people saved a trip to The hospital or even calling an ambulance because the helmet saved them. 

 

I witnessed two crashes very recently where the person walked away, but their helmet was a complete shattered mess. That would have been their head and yes it is personal choice, but no one complains about wearing a seat belt. Please don’t say there is data, because the data we need re Helmets has not been gathered. Go visit a&e and see head injuries. 

If the police get involved why not, remember it’s them who have all the paperwork, investigation and having to give the family the bad news

If a bike helmet is a “complete shattered mess”, it means that the energy involved was much greater than the helmet was designed to protect against. The main protection from a bike helmet comes from compressing the expanded polystyrene inside it, not from the thin plastic outer that holds it together, so if the helmet shatters, it means it’s not doing its job correctly and most likely provided only very minimal protection.

Real life impacts are very complicated actions, and it’s entirely possible that the inital ‘killing’ impact deformed the helmet and protected the wearer, but also ruined the integrity of the helmet such that subsequent smaller impacts destroyed the now substantially weakened helmet, but those impacts were not capable of doing serious damage to the encased skull. So, a destroyed helmet does not mean either that it was subject to impacts outside it’s design envelope, nor that it offered skant protection. Just because an air bag is a torn bloody, muddy floppy mess and the vehicle didn’t stop when it deployed doesn’t mean that the air bag offered no protection at the time of impact. 

I get your point, but does that mean you support the opposite view, that if a helmet is destroyed it means that it provided a high level of protection? That’s what I was arguing against.

If a helmet is destroyed, as I pointed out, it may have provided a high level of protection, but  for sure there will be instances where the helmet provided negligible protection and was destroyed. I think these may be the minority of cases where the rider survived though. To me it’s hard to envisage an impact destructive enough to destroy a helmet that wouldn’t have had fairly devastating effects on the head contained within  had it not been there, which is really what saying ‘it provided negligible protection’ means

I’m not convinced as the general design of bike helmets has very clear structural weaknesses (or vents as they are often called) and any non-flat object hitting a helmet has a reasonable chance of destroying it. Your argument that a destroyed helmet most likely provided significant protection is begging the question.

I don’t think any of it is as absolute as your alterrnative proposition “the opposite view, that if a helmet is destroyed it means that it provided a high level of protection?”.  And at this point we get to semantics, because I’m uncomfortable with “most likely” but comfortable with “fairly likely”.  I take your point about the vents and a non-flat surface (eg rock or top of  fence post) but what would the effect on the skull be in the absence of the helmet. I think it’s going to be generally unlikely that in the event a helmet is destroyed (I was envisaging the majority of the  helmet being in pieces) that an unprotected skull in the same instance wouldn’t have benefitted from a helmet between it and the striking surface.

I think we need some experimenters to figure out the real value of destroyed helmets.

I just object to the naive view that a destroyed helmet must have provided significant protection, when I would expect the opposite to be more likely.

 

Well, I nominate Donald Trump as crash test dummy #1

 

I don’t think the opposite is more likely, and just because it’s a naiive view doesn’t mean it’s wrong 🙂

Really, to my mind, the crux of that argument is given that a head was encased in the helmet at time of destruction, and significant force is likely to have been applied to destroy it,  what would have been the state of the head had the helmet not been there. Generally speaking I think the answer has to be “worse”, probably normally coupled with “considerably”. 🙂

By the way, I meant “naive” as in the mother’s views – I think most people on this forum have read at least some discussions of helmet efficacy.

A problem with using a destroyed helmet as a signature of a high level of protection, is that it leads to the paradox whereby the weaker the helmet, the more often it is judged to have provided protection.

My view on bike helmets is that they are good at protecting against scrapes and possibly minor skull fractures, but next to useless in preventing brain damage due to the brain ‘sloshing’ against the inside of the skull. Combined with the data that shows drivers give less space to helmet wearing riders, and I think that their net benefit is negligible.

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

wknight wrote:

The one key statistic we are missing is how many people saved a trip to The hospital or even calling an ambulance because the helmet saved them. 

 

I witnessed two crashes very recently where the person walked away, but their helmet was a complete shattered mess. That would have been their head and yes it is personal choice, but no one complains about wearing a seat belt. Please don’t say there is data, because the data we need re Helmets has not been gathered. Go visit a&e and see head injuries. 

If the police get involved why not, remember it’s them who have all the paperwork, investigation and having to give the family the bad news

If a bike helmet is a “complete shattered mess”, it means that the energy involved was much greater than the helmet was designed to protect against. The main protection from a bike helmet comes from compressing the expanded polystyrene inside it, not from the thin plastic outer that holds it together, so if the helmet shatters, it means it’s not doing its job correctly and most likely provided only very minimal protection.

Real life impacts are very complicated actions, and it’s entirely possible that the inital ‘killing’ impact deformed the helmet and protected the wearer, but also ruined the integrity of the helmet such that subsequent smaller impacts destroyed the now substantially weakened helmet, but those impacts were not capable of doing serious damage to the encased skull. So, a destroyed helmet does not mean either that it was subject to impacts outside it’s design envelope, nor that it offered skant protection. Just because an air bag is a torn bloody, muddy floppy mess and the vehicle didn’t stop when it deployed doesn’t mean that the air bag offered no protection at the time of impact. 

I get your point, but does that mean you support the opposite view, that if a helmet is destroyed it means that it provided a high level of protection? That’s what I was arguing against.

If a helmet is destroyed, as I pointed out, it may have provided a high level of protection, but  for sure there will be instances where the helmet provided negligible protection and was destroyed. I think these may be the minority of cases where the rider survived though. To me it’s hard to envisage an impact destructive enough to destroy a helmet that wouldn’t have had fairly devastating effects on the head contained within  had it not been there, which is really what saying ‘it provided negligible protection’ means

I’m not convinced as the general design of bike helmets has very clear structural weaknesses (or vents as they are often called) and any non-flat object hitting a helmet has a reasonable chance of destroying it. Your argument that a destroyed helmet most likely provided significant protection is begging the question.

I don’t think any of it is as absolute as your alterrnative proposition “the opposite view, that if a helmet is destroyed it means that it provided a high level of protection?”.  And at this point we get to semantics, because I’m uncomfortable with “most likely” but comfortable with “fairly likely”.  I take your point about the vents and a non-flat surface (eg rock or top of  fence post) but what would the effect on the skull be in the absence of the helmet. I think it’s going to be generally unlikely that in the event a helmet is destroyed (I was envisaging the majority of the  helmet being in pieces) that an unprotected skull in the same instance wouldn’t have benefitted from a helmet between it and the striking surface.

I think we need some experimenters to figure out the real value of destroyed helmets.

I just object to the naive view that a destroyed helmet must have provided significant protection, when I would expect the opposite to be more likely.

madcarew wrote:

hawkinspeter wrote:

madcarew wrote:

hawkinspeter wrote:

wknight wrote:

The one key statistic we are missing is how many people saved a trip to The hospital or even calling an ambulance because the helmet saved them. 

 

I witnessed two crashes very recently where the person walked away, but their helmet was a complete shattered mess. That would have been their head and yes it is personal choice, but no one complains about wearing a seat belt. Please don’t say there is data, because the data we need re Helmets has not been gathered. Go visit a&e and see head injuries. 

If the police get involved why not, remember it’s them who have all the paperwork, investigation and having to give the family the bad news

If a bike helmet is a “complete shattered mess”, it means that the energy involved was much greater than the helmet was designed to protect against. The main protection from a bike helmet comes from compressing the expanded polystyrene inside it, not from the thin plastic outer that holds it together, so if the helmet shatters, it means it’s not doing its job correctly and most likely provided only very minimal protection.

Real life impacts are very complicated actions, and it’s entirely possible that the inital ‘killing’ impact deformed the helmet and protected the wearer, but also ruined the integrity of the helmet such that subsequent smaller impacts destroyed the now substantially weakened helmet, but those impacts were not capable of doing serious damage to the encased skull. So, a destroyed helmet does not mean either that it was subject to impacts outside it’s design envelope, nor that it offered skant protection. Just because an air bag is a torn bloody, muddy floppy mess and the vehicle didn’t stop when it deployed doesn’t mean that the air bag offered no protection at the time of impact. 

I get your point, but does that mean you support the opposite view, that if a helmet is destroyed it means that it provided a high level of protection? That’s what I was arguing against.

If a helmet is destroyed, as I pointed out, it may have provided a high level of protection, but  for sure there will be instances where the helmet provided negligible protection and was destroyed. I think these may be the minority of cases where the rider survived though. To me it’s hard to envisage an impact destructive enough to destroy a helmet that wouldn’t have had fairly devastating effects on the head contained within  had it not been there, which is really what saying ‘it provided negligible protection’ means

I’m not convinced as the general design of bike helmets has very clear structural weaknesses (or vents as they are often called) and any non-flat object hitting a helmet has a reasonable chance of destroying it. Your argument that a destroyed helmet most likely provided significant protection is begging the question.