Which piece of motorcycle protective gear is statistically the most effective at reducing fatal injuries?

HELMET EFFECTIVENESS: NHTSA data consistently shows helmets are the most effective single piece of motorcycle protective gear: Reduce death risk by 37%; reduce serious head injury risk by 67%; save approximately 1,800 lives annually in the US; HEAD INJURY IN CRASHES: Head injuries are the leading cause of motorcycle fatality — the brain is fragile and the skull alone does not provide adequate protection at crash speeds; HELMET TYPES: FULL FACE (best protection — covers entire face including chin); MODULAR (flip-face, good protection); OPEN FACE (protects skull but not face/chin — common facial injury point); HALF HELMET (minimal protection); DOT CERTIFICATION: Must display DOT sticker certifying compliance with FMVSS 218; SNELL certification is a more rigorous voluntary standard; ATGATT: 'All the gear, all the time' — the MSF and experienced riders advocate full protective gear on every ride; MSF data shows 90%+ of crash injuries occur on rides of less than 5 miles.