Montana DUI Laws

Montana DUI Laws

While all states criminalize driving under the influence of alcohol or drugs, each state has a different set of laws that apply. In Montana, the charge is called Driving Under the Influence (DUI) and a charge of DUI can lead to criminal and administrative penalties (suspension or revocation of driver’s license). If you or someone you know has been charged with DUI, it is important that you understand the laws related to this charge.

In Montana, you can be charged with DUI in a number of circumstances. Montana criminalizes driving under the influence of alcohol, a drug, and/or a combination of the two. It is important to remember that you can be charged with DUI for driving under the influence of a prescribed drug (including medical marijuana) if that drug has diminished your ability to safely operate a vehicle (including ATV’s, snowmobiles, and other motorized vehicles). The State will attempt to prove your diminished ability as a result of your driving behavior, your performance on Standardized Field Sobriety tests, and chemical tests (breath and blood testing). At each step in the process, however, law enforcement can and does make mistakes.

In addition to charging you with DUI because your ability to safely operate a vehicle has been diminished, the State can charge you with a DUI, per se, any time you provide a chemical test that demonstrates your blood alcohol content (BAC) is at or above 0.08% or your blood shows a concentration of 5 ng/ml of active marijuana.

If charged with DUI, per se, the State does not have to prove at trial that your driving ability was diminished—rather, the State is required only to prove that your BAC was at or above 0.08% or that there was 5 ng/ml of marijauana in your system at the time you were driving. The State must, however, prove that the testing and the result are accurate and reliable—a task at which the State can and does fail.


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Photo credit:Mark Blackford