We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
Helmet saved me in two major accidents: once hit by a car while I was in the bike lane; another when I went down after a light shower -- my head bounced three times on the asphalt. I got up unharmed, but stunned.
There's no doubt that falling head first onto pavement with a helmet is less damaging to your head than doing so without a helmet. The trouble is this is the least likely thing to happen to you on a bicycle. The most common accidents on a bike are low speed falls that result in broken arms and wrists. The other most common accident is a fall that breaks an ankle.
Then there are the big ones, like being hit by a car and having your head slammed violently into something hard like a car or the pavement. They are very rare and most helmets offer little protection. A cheap hunk of plastic on your head is just not much use in these situations.
There's also data showing that motorists are much more cautious when near a rider not wearing a helmet than one with a helmet. Riders most certainly feel safer and therefore less cautious. As is always the case, there's a lot of moving parts to consider.
The bottom line is that helmet is not causing harm and not doing much good, but in our highly feminized age, most people will wear them.
John Adams wrote a book on the effect of road safety regulations which you can download for free. He contends that all the safety regulations cause people to alter their behavior to increase the level of risk to the level they are
My son's bike helmet may have saved his brain and functional life. Six years old, stove into a cement curb and fell over onto that curb, the helmet - plastic shell and styrofoam layer both - was cracked in two places on the right-hand side. He got a broken arm as well, but his head was OK. I am sole caregiver for a TBI patient, not my son, so I know deeply the bullet my son dodged. I thank G-d he was wearing that helmet.