It seems clear that a) the emergency medical people have gotten
gradually better at their job (probably in large part due to
technology), and b) helmets aren't making a significant difference in
cyclists' fatalities. If they were, the cyclist plot would drop
relative to the ped. plot.


This whole helmet discussion reminds of my pesticide chemistry
class when my prof. would tell the class "but the LD50 is ...
blah, blah, blah.", but never took into account that while maybe
it takes a lot of whatever chemical to kill you, no one really
knows how much it takes to cause cancer, nerve damage,
brain damage, loss of eyesight, etc....

The same thing holds true for this discussion. You're looking
at FATALITIES. What about the accidents where a helmet
prevented brain injury? It's not something that can be answered
or tested easily....

And I'll wear mine thank you, I've hit enough low hanging
tree branches while MTB riding to know they help.