I work in trauma services, and you wouldn't believe the horrific motorcycle injuries that come into the ER. The most recent was a human wishbone -- t-boned a garbage truck and exsanguinated. There is nothing doctors can do to fix an injury like that. Many of these riders think if they wear a helmet they are safe which is far from reality.
Oh, I understand that all too well.
Federal Motor Vehicle Safety Standard 218 which states the requirements for helmes only tests helmets for 15mph and has ZERO, ZIP, and NADA stardards for neck stress.
(shorthand is FMVSS 218)
One last point hemets are not certified by the DOT. The manufacturer self certifies compliance with FMVSS 218. The snell standard has no effect at law, only DOT certified by the manufacturer matters.
I won't get too specific, but the director of a major DFW ER, rides a Harley.