Motorcycle helmet laws by state

What the numbers show — and what they don't

Among motorcyclists killed in 2023 whose helmet use was recorded, 90% wore a helmet in all-rider-law states, 50% in age-limited states, and 36% in states with no law. That is a clean measure of how laws change behaviour: where a helmet is required, almost everyone wears one.

It is not a measure of whether helmets save lives, and the death rates by law type should not be read that way. Deaths per 10,000 registered bikes are 6.3 in all-rider states, 7.1 in age-limited states and 5 in the three no-law states — but the no-law group is Illinois, Iowa and New Hampshire, with short riding seasons, and the all-rider group includes California and the year-round South. Comparing them compares climates. NHTSA's own estimate, from a study that compares riders and passengers in the same crashes, is that a helmet cuts a rider's risk of a fatal injury by 37% (DOT HS 809 715).

Why it matters for insurance

Where helmet laws touch insurance is through injury severity: head injuries are the largest medical claims in motorcycling, so the injury coverages — medical payments, UM/UIM, and personal injury protection where a state has it — are worth most in states where helmet use is lowest.

Every state's law

Sources: IIHS motorcycle helmet law table (current as of October 2026); NHTSA Traffic Safety Facts 2023 Data: Motorcycles (DOT HS 813 732), Table 7. Helmet share by law type is weighted by deaths. Checked 2026-10-23.