On Tuesday, September 22, 2015 at 1:01:03 PM UTC-7, The Real Bev wrote:
On 09/20/2015 04:04 PM, wrote:

I could go into great detail about helmets since I started learning
about them as the Safety Director of the American Federation of
Motorcyclists about the time Bell started and I had some long
discussions with people at Bell. I am also an engineer and a
scientist. I wrote one of the few peer reviewed papers on bicycle
helmets.

Long ago I had/read a USAF publication about helmet design which had a
lot of useful/interesting information. I recently did a google etc.
search for it and turned up nothing. Did you ever read that?

Helmets are capable of VERY little and at the cost of setting you up
for two other kinds of killer injuries.

I wear one because they are good for one thing - keeping your head
from getting gravel rash in a mild crash. In harder crashes they can
cause severe concussions or broken necks. Funny thing - evolution
didn't design your head like a helmet for a reason.

I remember reading that they were designed to "protect" the head from a
6-foot fall straight down. An unlikely occurrence, I think...

The majority of accidents to adults are the fault of the car. An
approaching driver making a sudden left turn. And a car approaching
from behind, accelerating to pass you and then suddenly turning
right.

The left turn danger is MUCH reduced if you wear bright clothing.
This both makes you much easier to see to the approaching driver plus
it makes it more difficult for the driver to guess your speed making
him think you are faster than he might otherwise think.

I favor as much neon-color as possible -- the guy who hits me is NOT
going to be able to tell the judge he didn't see me.

The "right hook" is impossible to prevent. But you can be aware of
the sounds of a driver about to pull this dumb stunt.

Bev, I remember little about Air Force helmets and I was in the Air Force and had to wear them upon occasion. They had almost no protection of any sort. They had a rather medium strength padding if memory serves and were hard shelled to protect your head from being slapped against the areas around your cockpit seat. Because of the peculiarities of a B52 there was little to no chance that I could survive in case of aircraft damage. So I didn't worry about it. That led to insanities such as crawling to and from the tail gunners position on an 8" wide shelf. On the way back we were under fire and on the way back the bomb bays were open. Imagine leaning two feet to your side while crawling on an 8" shelf and the only way to hold on was to hook two fingers into a slight opening where the fore/aft and latitudinal ribs crossed. Scoot up a couple of inches and repeat until arrival. It would only take 5 minutes.

Bell started out to build helmets for motorcyclists. Very simple calculations using medical data on the strength of the skull and the neck's ability to withstand whiplash set an upper limit on the weight of a helmet.

Later for bicycles this was modified slightly for calculations on the maximum size of a helmet and a person in athletic pursuits would wear. In both cases the size of the helmet came out very closely the same.

BUT --- Since the size of the helmet was limited and the strength of the skull likewise, the material that the padding could be made out of became quite limited.

So they designed the helmet to be capable of APPROXIMATELY a six foot fall onto a hard flat surface with no protrusions.

The motorcycle helmet's hard shell was designed to protect the skull and later the face in a crash in which the head was dragged along the ground. As a person that has gone through a number of helmets while racing I can tell you that the normal fall is in a turn and losing traction and going down. Your head does NOT hit first and the blow is rather small. And the helmet is very effective in this manner.

On the bicycle helmet however, it was designed to take a single fall and not fracture the skull.

Unfortunately they did not consult Mother Nature. The limits of the strength of the skull are not simply the weight of the head and the strength of bone. The strength has actually been part of evolution and the skull is designed to fracture and cushion the brain in that manner before allowing concussions. Concussion is from the accelerative forces tearing the brain away from the skull (most often on the opposite side from the blow) and allowing it to smash into the area of the strike.

A fractured skull is very dangerous but can be survived. Concussion is damage to the brain itself and not only may not be survived but surviving, the brain may become more or less inoperable. This is commonly shown in injuries to boxers or football players who are only using the strength of the human body without the additions of gravity.

But the ability of the helmet to prevent skull fracture enhances the ability of a fall to cause serious concussion. In me it causes intermittent seizures that can totally eliminate any short and long term memory to the point where I don't even remember to eat or drink. It is controlled by twice daily medication which has taken me three years to get used to the side effects of dizziness and the brain damage which makes the forward part of the feet unfeeling and hence balance difficult. But you ALSO have a balance mechanism tied to your hips and so I can ride a bike fine even though I have to walk like a duck to retain my balance.

It happened to me when I was bending over to move the front wheel speedo pickup out a little to stop the ticking. My head was only three feet off of the ground when the front fork fell apart and dropped me on my head. The helmet was completely crushed. The bones on one brow ridge were broken BY THE HELMET. I was unconscious for over five minutes. One eye (or section of the brain) was damaged so that things appear larger in one eye than the other.

The fork I was using was a first generation carbon fiber fork that was incorrectly made so this is a highly unlikely event but demonstrates that a helmet has effectively no ability to protect a cyclist.

There is perhaps one chance in thousands that in a normal street accident that a helmet could actually help you. And more than that, that it can harm you.

What the heck - I'll hope for a help and not a harm since I'm a careful cyclist.

But the truth of the matter is that street accidents are entirely outside of the ability of a helmet to cope with. Most accident involve motor vehicles at speeds of 25 mph or higher. So if someone decides to not wear a helmet don't rag on them because it isn't doing YOU any good to have one.