A while back I was reading a discussion on helmets on this forum...someone posted a diagram of a helmet that basically outlined the helmet like a pie chart that was depicting impact areas during a crash...it showed what percentage of the helmet received to most impacts over the course of X amount of crashes. I remember the chin area receiving the highes pertantages (the most impacts) ...anyone seen this or something similar they could share...I'm sure I saved that pic, but not sure what I did with it.
I guess the chin gets the most hits because people want to see where they are going.
I learned in Airborne school to do a good PLF (parachute landing fall) part of which teaches to tuck the chin and do what you can to not eat dirt.