In a state with more horses, snowmobiles, and drift boats than most, this question is not just trivia. The answer comes from definitions. Montana's DUI statute applies to a person who drives or is in actual physical control of a vehicle (MCA § 61-8-1002), so everything depends on what counts as one. This page is part of our Montana DUI Guide.
The Short Version
| What you were on or in | Montana DUI statute? | Why |
|---|---|---|
| Car, truck, motorcycle | Yes | A vehicle under MCA § 61-1-101. |
| Bicycle | No | For the DUI laws, "vehicle" does not include a bicycle (MCA § 61-8-1001(15)). |
| Electrically assisted bicycle | No, if it meets the statutory definition | "Bicycle" includes an electrically assisted bicycle: two tandem wheels and a motor that tops out at 20 mph (MCA § 61-8-102). |
| Horse or horse-drawn wagon | No | "Vehicle" excludes devices moved by animal power (MCA § 61-1-101). |
| Moped or motorized scooter | Yes, on the statute's text | Each is defined as a vehicle and neither is excluded. |
| ATV, side-by-side, snowmobile, golf cart, riding mower | It depends on where | The DUI statute reaches any "vehicle," not only motor vehicles. Location matters, and no Montana Supreme Court case we found settles it. |
| Motorboat, or waterskis towed by one | Separate offense | Boating under the influence, MCA § 23-2-523. |
How Montana Defines a Vehicle
The general definition is broad: a vehicle is "a device in, on, or by which any person or property may be transported or drawn on a public highway, except devices moved by animal power or used exclusively on stationary rails or tracks" (MCA § 61-1-101). It also excludes a wheelchair or similar mobility device used by a person with a physical disability. Note that it does not say "motor." The DUI statute reaches vehicles, not only motor vehicles.
The DUI part of the code then narrows it once: for these laws, the term "does not include a bicycle" (MCA § 61-8-1001(15)).
Bicycles and E-Bikes
A bicycle is out by express exclusion. Montana's traffic code defines a bicycle as a vehicle propelled solely by human power and adds that the term includes an electrically assisted bicycle (MCA § 61-8-102). Read together, an e-bike that meets the statutory definition, two tandem wheels with a motor that cannot push it past 20 miles an hour, is a bicycle and is excluded too.
Two cautions. A machine that is faster or built differently may fall outside that definition. And a moped or motorized scooter is defined separately as a vehicle, with no exclusion, so on the text of the statute the DUI law applies to them.
Horses
A horse is not a "device," and a wagon or buggy drawn by one is a device "moved by animal power," which the definition excludes. The DUI statute does not reach either. That is as far as this page goes: other laws may apply to what a person does while intoxicated, and an impaired rider on a road is in real danger.
ATVs, Side-by-Sides, Snowmobiles, and Golf Carts
These are devices by which a person can be transported, so they can be vehicles. Montana's snowmobile and off-highway vehicle chapters do not contain their own DUI section. Whether the DUI statute applies then turns on location:
- An alcohol DUI applies on the "ways of this state open to the public," which means a highway, road, alley, lane, parking area, or other public or private place adapted and fitted for public travel and in common use by the public (MCA § 61-8-102(29)).
- The provisions on driving under the influence of drugs apply anywhere within the state (MCA § 61-8-101(2)).
Riding an ATV down a county road after drinking is plainly within the statute. A snowmobile on a remote trail or a side-by-side in your own field is less clear, and we did not find a Montana Supreme Court decision that settles it. If you have been charged in that kind of setting, whether the location qualifies is a real issue to raise.
Boats: A Separate Law
Operating a motorboat under the influence is prohibited by the boating code, not the DUI statute. MCA § 23-2-523 covers a motorboat, a sailboat propelled by a motor, and waterskis, a surfboard, or a similar device towed by a motorboat. A violation is a misdemeanor punishable by a fine of not less than $15 or more than $500, imprisonment for up to 6 months, or both (MCA § 23-2-507).
Testing works differently on the water. The same inferences from an alcohol concentration apply, but if a person refuses a test none will be given, and proof of the refusal is admissible (MCA § 23-2-535). The statute does not state a driver's license suspension for that refusal. The statute speaks of motorboats and devices towed by them.
Why This Matters in a Real Case
These definitions are not only curiosities. If the thing you were operating is not a vehicle, or the place was not a way open to the public, the State cannot prove an element of the offense. A related question is whether you were "in actual physical control" at all, which we cover in sleeping in your car and actual physical control.
This page explains Montana law in general as of the 2025 Montana Code Annotated. Where we say the law is unsettled, we mean it. It is not legal advice about your specific case.