Under the Montana motorcycle helmet law, only riders and passengers under 18 are required to wear a helmet. Once you turn 18, the state leaves the choice to you. That doesn’t mean the decision is cost-free for adults, but as a matter of traffic law, an adult can ride bare-headed in Montana without breaking any rule.
Who Has to Wear One
Montana Code Annotated 61-9-417 requires every motorcycle operator and passenger under 18 to wear protective headgear on any public street or highway.1Montana Code Annotated. Montana Code Annotated 61-9-417 – Headgear Required for Minor Motorcycle Riders Age is the only factor. It doesn’t matter whether the minor holds a full license, a learner’s permit, or nothing at all.
The operator carries a second duty on top of their own: you cannot ride on a highway with a passenger under 18 who isn’t wearing a helmet.1Montana Code Annotated. Montana Code Annotated 61-9-417 – Headgear Required for Minor Motorcycle Riders Give a 16-year-old a lift without a helmet and you’re the one who gets cited. No exception for short trips, side streets, or slow speeds.
Which Vehicles the Law Covers
The rule reaches beyond full-size bikes. It applies to motorcycles, mopeds, motorized scooters, and quadricycles.1Montana Code Annotated. Montana Code Annotated 61-9-417 – Headgear Required for Minor Motorcycle Riders A teenager on a moped needs a helmet just like a teenager on a touring bike.
One exception matters. Autocycles that are fully enclosed, with a windshield, nonremovable doors, and a roof, are exempt from the helmet rule even for minors.1Montana Code Annotated. Montana Code Annotated 61-9-417 – Headgear Required for Minor Motorcycle Riders An autocycle is a three-wheeled motorcycle with safety belts, roll bars, a steering wheel, and a seat you sit in rather than straddle. The enclosed shell is treated as protection enough.
What Counts as a Legal Helmet
A helmet worn to satisfy the law must meet the standards set by Montana’s Department of Justice. The Department has adopted Federal Motor Vehicle Safety Standard (FMVSS) 218 and ANSI Standard 290.1-1971, with FMVSS 218 controlling if the two conflict.2Cornell Law Institute. Montana Administrative Rule 23.3.417 – Standards for Protective Headgear The upshot: a standard DOT-certified motorcycle helmet meets Montana’s requirement.
Check the back of the helmet for the DOT label. A compliant label lists the manufacturer or brand, the model, and the words “DOT” and “FMVSS No. 218.” Real helmets have a thick, stiff foam liner and a chin strap held on with solid rivets. Novelty lids, bicycle helmets, and hardhat-style gear won’t qualify. A foam liner thinner than an inch is a strong sign the helmet doesn’t meet the standard.3National Highway Traffic Safety Administration. Choose the Right Motorcycle Helmet
The Fine for a Violation
A conviction for violating the helmet law carries a $5 fine.4Montana Code Annotated. Montana Code Annotated 61-9-518 – Violation of Motorcycle or Quadricycle Requirements That’s one of the smallest traffic fines in the country. The citation still creates a formal record of a traffic offense, but the ticket itself is not where the real money is at risk.
How Going Helmetless Can Cost an Adult After a Crash
The bigger financial stake shows up in injury claims, and it applies to adults who legally skip the helmet. Montana follows a modified comparative negligence rule. If you’re partially at fault for your own injuries, your compensation gets cut by your percentage of responsibility. If your share exceeds 50%, you recover nothing.5Montana Code Annotated. Montana Code Annotated 27-1-702 – Comparative Negligence
Head injuries often drive the largest share of medical bills after a motorcycle crash. A defense lawyer will argue that a helmet would have prevented or reduced those injuries and that your choice to ride without one should count against your recovery. Riding helmetless doesn’t automatically bar your claim, but it can shrink what you collect and, in a serious case, push your fault past the 50% line that ends the claim entirely.5Montana Code Annotated. Montana Code Annotated 27-1-702 – Comparative Negligence The law lets adults ride bare-headed. The insurance adjuster is a different conversation.