No it doesn't. I've heard of people dying while wearing a helmet. They received serious internal injuries, and suffered no head trauma. I've heard of guys dying WITHOUT a helmet on, and had no head trauma. I love seeing an 18yr old dipshit, riding a 1200cc crotch rocket, while wearing a $500 helmet...and a tank top, shorts, tennis shoes, without socks, and he rides like he's been doing it for 20 years. I do my best to be safe, I go out for a putt, I ride like everyone else is an asshole, and I have no problem with backing off, to let a fucktard go by. But to think a helmet, or full leathers will save you, isn't really that logical to me. It may help, but I believe, as I've said, when he wants you, he gets you, and it's his choice...a helmet won't save you from your time.
You never hear of people dying while wearing a helmet, because the news won't report that...just like they never tell you an automobile accident victim was wearing a seat belt, but the first thing you hear when they weren't, is that they weren't. Another one, just to through it out there, are guns. You always hear the bad side, but you never hear when an old lady saves her life, and the life of her grand children.