In Montana you cannot get a DUI on a bicycle, and an e-bike that meets the statutory definition counts as a bicycle. A moped or a motorized scooter is different: each is defined as a vehicle, and nothing in the DUI laws excludes them. This page sorts the common devices into those categories. It is part of our Montana DUI Guide and expands on our overview of DUI on a horse, bike, ATV, or boat.
Start With the Word Vehicle
The impairment offense applies to a person who drives or is in actual physical control of "a vehicle" on the ways of this state open to the public (MCA § 61-8-1002(1)(a)). A vehicle is a device in, on, or by which a person or property may be transported or drawn on a public highway (MCA § 61-1-101). The DUI part of the code then narrows the word once: it "does not include a bicycle" (MCA § 61-8-1001(15)).
So the question for any two-wheeled or stand-up device is whether Montana law calls it a bicycle. If it does, the DUI statute does not apply. If it does not, the device is very likely a vehicle.
Device by Device
| Device | How the code defines it | DUI statute | MCA |
|---|---|---|---|
| Pedal bicycle | Propelled solely by human power, any number of wheels | Excluded | §§ 61-8-102(2), 61-8-1001(15) |
| Electrically assisted bicycle | Two tandem wheels; motor cannot propel it and a 170-pound rider faster than 20 mph on a paved, level surface | Excluded, because it is a bicycle | § 61-8-102(2), (7) |
| Faster or differently built e-bike | Does not meet the definition above | Not within the bicycle exclusion on the text | § 61-8-102(7) |
| Moped | Two or three wheels, pedals, power source of 2 brake horsepower or less, 30 mph or less unassisted, automatic drive | A vehicle; not excluded | § 61-8-102(14) |
| Motorized scooter | No seat; power source cannot exceed 30 mph on a level surface | A vehicle; not excluded | § 61-8-102(15) |
| Motorized skateboard, pocket bike | Motorized nonstandard vehicle: small wheelbase and wheels, no VIN | A vehicle; not excluded | § 61-1-101 |
| Wheelchair or mobility device for a person with a disability | Manually or mechanically propelled | Not a vehicle | § 61-1-101 |
The right-hand conclusions for mopeds, scooters, and nonstandard vehicles are our reading of the statutory text. No published Montana Supreme Court opinion we found has decided them.
E-Bikes: The 20 Mile an Hour Line
Montana's definition of an electrically assisted bicycle is short and specific. It does not use the Class 1, 2, and 3 labels that manufacturers and many other states use. It asks two things: does the machine have two tandem wheels, and is its electric motor capable of propelling it and a 170-pound rider no faster than 20 miles an hour on a paved, level surface (MCA § 61-8-102(7))?
An e-bike sold with a higher assisted top speed, an aftermarket controller, or a three-wheel layout may not fit. If it does not, it loses the label that carries the DUI exclusion. Depending on its pedals, power, and speed, it could instead meet the definition of a moped. In a contested case, the specifications of the actual machine would be evidence, and the State would have to prove it was operating a vehicle.
Mopeds and Motorized Scooters
Both definitions begin with the words "a vehicle." The motorized scooter definition adds that the term "does not include an electrically assisted bicycle," which confirms the Legislature treated the two as separate things (MCA § 61-8-102(15)).
There is a wrinkle. The general definition of "motor vehicle" excludes a bicycle, a motorized scooter, a moped, an electric personal assistive mobility device, and a motorized nonstandard vehicle (MCA § 61-1-101). That matters for some DUI-related rules and not others:
- The impairment offense is written for "a vehicle," so the motor vehicle exclusion does not help (MCA § 61-8-1002(1)(a)).
- The 0.08 per se offense is written for "a noncommercial vehicle," a term the traffic code defines in terms of motor vehicles (MCA § 61-8-102(16)). Whether that takes a moped or scooter outside the per se offense is an argument a lawyer can raise. It is not a settled rule.
- The open container law applies to the passenger area of a "motor vehicle" on a highway (MCA § 61-8-1026), so by its terms it is aimed at cars and trucks.
- The implied consent law applies to a person operating "a vehicle" (MCA § 61-8-1016(1)(a)), so a refusal on a moped or scooter can carry a license suspension.
Our page on per se and impairment DUI explains the difference between the two kinds of charge.
Hoverboards, One-Wheels, and Other Devices
The code defines a "motorized nonstandard vehicle" as a self-powered vehicle with a wheelbase under 40 inches and wheels under 10 inches that lacks a manufacturer's certification or 17-character VIN, and it gives a motorized skateboard and a "pocket rocket" as examples. Because the definition calls it a vehicle, the impairment offense can reach it on the text.
An "electric personal assistive mobility device" is a self-balancing device with two nontandem wheels, limited to 12.5 miles an hour. The code calls it a device rather than a vehicle, and we found no decision on how the DUI law treats it. For newer products that fit none of these definitions, there is no reliable answer yet.
Where You Were Riding
The place matters too. An alcohol DUI applies on the ways of this state open to the public: streets, alleys, parking areas, and other places fitted for public travel and in common public use (MCA § 61-8-102(29)). A city street or a parking lot qualifies. Whether a particular path or trail does is a fact question, covered in our page on private property and parking lots.
If You Are Charged
A scooter or moped DUI is prosecuted like any other, with field sobriety testsand a breath or blood test. What is different is the first defense question: was this machine a vehicle under the DUI part at all? Photographs, the owner's manual, the motor rating, and the top assisted speed are worth preserving right away.
This page explains Montana law in general as of the 2025 Montana Code Annotated. Where we say a point is our reading of the text or is unsettled, we mean it. It is not legal advice about your specific case.