The last study I looked at, think it was the Hurt report done in 1981, said there was a 29% reduction in fatalities with a helmet. The protection afforded by a helmet has improved dramatically since 1981 if you consider a full face ECE 22.05 or Snell M2010 approved helmet. Still most riders do not wear them if they wear a helmet. Most cruiser riders prefer a 1/2 helmet, some of which are not even DOT approved. 39% of head impacts are to the face and chin. I have not seen a helmet study that considers they type of helmet but if there was one I think the protection of a good full face helmet would raise the figure of 29% a lot higher.
Not wearing a helmet or gear is simply Darwin’s theory in action.
“Let me get this strait, the helmet law is to protect a brain that lacks the judgment to protect itself unless it was forced to?” – Seinfeld