Drink-driving limits in Montana (2026)

Last reviewed: 29 October 2026

In short: Montana sets its own drink-driving rules. The general limit is 0.08% blood alcohol. Fields not shown are not yet verified.

Rule	What applies
Blood alcohol limit for ordinary driversDriving after drinking alcohol	0.08 % blood alcohol ^[1]
Lower limit for novice or young driversDriving after drinking alcohol	Under 21 at the time of the offence: an offence at an alcohol concentration of 0.02 or more. ^[1]
Random breath tests without suspicionDriving after drinking alcohol	⚠ Not yet verified
Limit for professional or commercial driversDriving after drinking alcohol	Driving a commercial motor vehicle with an alcohol concentration of 0.04 or more is the offence of driving under the influence. ^[2]
Maximum penaltiesDriving after drinking alcohol	First violation of driving under the influence at 0.08 or more: imprisonment of up to 6 months and a fine of $600 to $1,000 (a first violation of the impairment offence carries 24 hours to 6 months and the same fine). With a passenger under 16 the fine is $1,200 to $2,000. ^[3]

Sources

These rules are set at national level in the United States and apply here too, alongside the rules above. All national rules for the United States

Limit for professional or commercial drivers	0.04% alcohol concentration or more: a driver subject to commercial driver's licence rules must not report for or remain on duty performing safety-sensitive functions, and an employer who knows of it must not let the driver continue. (source: Electronic Code of Federal Regulations (Office of the Federal Register))

State	Blood alcohol limit for ordinary drivers	Lower limit for novice or young drivers	Limit for professional or commercial drivers	Random breath tests without suspicion	Maximum penalties
Montana	0.08%	0.02% under 21	0.04% in a commercial vehicle	⚠ Not yet verified	Up to 6 months jail, $600-1,000 fine
Idaho	0.08%	0.02% (under 21)	0.04% (commercial vehicle)	⚠ Not yet verified	Up to 6 months; fine up to $1,000
North Dakota	0.08%	0.02% (under 21)	0.04% (commercial)	⚠ Not yet verified	1st: class B misdemeanour; fine min. $500
South Dakota	0.08%	0.02% (under 21)	0.04% commercial	⚠ Not yet verified	Up to 1 year; $2,000 fine
Wyoming	0.08%	0.02% (under 21)	0.04% (commercial vehicle)	⚠ Not yet verified	First: up to 6 months / $750

CannabisPossession for personal use: Legal for adults 21+, within limits · Growing at home: Yes: 2 mature plants, 2 seedlings
Car speed limitsBuilt-up areas: 25 mph · Outside built-up areas (single carriageway): 70 mph day / 65 night
Minimum age for a car driving licenceMinimum age for a car licence: 15 (after 6 months on a learner licence) · Earliest age to drive a car supervised: 14.5 with a traffic education course
E-bikes and speed pedelecsLegal class: Bicycle (one class)
FireworksConsumers may buy and use category F2 fireworks: Yes (permissible fireworks)
Knives and pepper sprayFolding pocket knives: Carry offence covers firearms only · Locking or one-handed knives: No section on automatic knives listed
Statutory minimum wageNational statutory minimum wage: Yes · Current adult minimum wage (gross): $10.85 per hour
Seat belts and child seatsSeat belt compulsory in front seats: Yes, every designated seat · Seat belt compulsory in rear seats: Yes, every designated seat
Tobacco and nicotine age limitsMinimum age to buy tobacco: 21 · Minimum age to buy e-cigarettes: 21
Drinking age and alcohol salesMinimum age to buy beer and wine: 21 (sales/provision banned) · Minimum age to buy spirits: 21 (sales/provision banned)

General information, not legal advice. Rules change: check the official source before you fly or ride.