On 5/15/2017 8:19 PM, Emanuel Berg wrote:
Frank Krygowski wrote:

I think most of them are convinced that if
they hadn't worn helmets all their lives,
bicycling would have killed them. Which is
really odd, considering that bike helmets
weren't available until the mid-1970s.

When the case is made helmets do not help, does
one mean the number of accidents with head
trauma hasn't decreased despite helmets being
sold or what exactly is the case?
Because obviously the helmet helps if one hits
it with a hammer...

Most of the "doesn't help" data involves looking at total injury or
fatality counts for entire countries, states or territories. As linked
upthread, Canadian and American bike and pedestrian deaths have dropped
over time, probably due to better emergency medical procedures; but
pedestrian deaths have actually dropped a bit faster. If cyclists were
getting protection from all the helmets, it seems cyclist deaths would
have dropped faster.

Australia imposed all-ages helmet laws in the early 1990s. Bicycling
immediately dropped something like 30% (although Mr. Scharf refuses to
believe that), but head injuries did not drop as much as bicycling.
That means the remaining bicyclists were actually at greater risk for
head injuries.

And back to America, bicyclist concussions have actually _increased_
greatly during the time when helmet use took off.

There have been various reasons proposed for this lack of observed
benefit. Some have noted that a helmet is a larger target than a bare
head, so in at least some crashes, a bare head might experience a near
miss, while a helmeted head would get an impact.

Some have noted that most brain injury comes from rotational, not
linear, impact; and a grazing blow on a helmet could impart sudden
rotation to the brain. (And most helmets aren't designed or certified
against rotation impact. Even MIPS helmets allow only a couple
millimeters of rotational motion.)

Some have pointed to Risk Compensation; and there have been studies that
show that helmeted cyclists do take a bit more risks.

Also, are we talking racing, MTB or any other
sport version, or are we talking
utility/commuting?

In this country, anyway, you're told to _always_ wear a helmet whenever
you ride your bike. I recall one promotion that said that you can fall
over and die even while standing over your bike in your own driveway.

Sanctioned races all require helmets. Athletic mountain bikers always
wear helmets - and they do take risks that they would not take without
them. As already mentioned, "sport" cyclists dress like their heroes,
and their heroes are now required to wear helmets in races.

There are very few helmet laws for adults in North America. (One city,
Seattle, does have such a law. Its bike share system just failed. I
wonder why?) Many states require kids to wear helmets. Those laws are
obeyed most often by upper-middle-class kids in nice neighborhoods,
especially when their parents use the car to take them to a nice safe
bike path. In my area, at least, most kids don't wear them otherwise.
That's true even over the state line (5 miles from my house) where there
is a kids' helmet law.


--
- Frank Krygowski