Sorry Mike, I misunderstood what you said in the message.
Thepup states that he has read helmets olny help in accidents below 30-35 miles and hour. When figuring out the kinetics of trauma, when it comes to both blunt force and penitrating trauma the formula that is used is Mass x Velocity squared.
So a 5 pound head hitting the pavement at 20mph would be figured out as 5 x 20 squared. SO the mass involved in trauma isnt as important as velocity. So in therory your helmet would be more important at higher speeds, IF the head was our only point of concern.
Outside of motocross I have actually worked very few motorcycle accidents where I could point to a helmet and state " that saved your life " and the ones whre I could were YOUNGER riders. And they didnt involve another vehicle most of the time.
Now if people would push proper clothing as much as they push helmets...... There is where a huge difference could be made. Here in Michigan as long as your wearing a helmet they dont care if your in shorts and flip flops