The DUI Stop and the Test
MCA 61-8-1016 — implied consent, the right to refuse, and a suspension of up to 1 year for refusing
A person who drives or is in actual physical control of a vehicle on the ways of the state open to the public is considered to have consented to tests of blood, breath or oral fluid for alcohol or drugs, including a preliminary breath screening test.
Who handles this in Montana: State Bar of Montana, Licensed Lawyer Montana; and legal aid programs and the state offices, listed in the Montana directory.
- The officer informs the person of the right to refuse the test, and that refusing will suspend the license for up to 1 year.
- A preliminary breath test does not satisfy the obligation to take the requested test.
- If the person refuses, the officer may apply for a search warrant for a blood or oral fluid sample.
A refusal is evidence. Proof that a person under arrest refused one or more tests is admissible in the criminal case arising from the driving.
Testing is also limited by the Fourth Amendment. The Supreme Court of the United States has held that a breath test may be taken without a warrant as part of a lawful arrest for drunk driving and a blood test may not; that a driver may not be criminally punished for refusing a blood test where no warrant was obtained; and that the natural fall of alcohol in the blood does not by itself create an emergency excusing a warrant in every case, which is decided case by case on all the circumstances. Those holdings are a floor: a state's own constitution and statutes can give more protection than they do, never less.
Sources for this section (4)
- MCA 61-8-1016 — Implied consent -- tests for alcohol or drugs -- refusal to submit -- administrative suspension of license
- MCA 61-8-1018 — Evidence admissible -- conditions of admissibility
- Birchfield v. North Dakota, 579 U.S. 438 (2016) — A breath test may be taken incident to arrest, a blood draw needs a warrant
- Missouri v. McNeely, 569 U.S. 141 (2013) — The natural fall of blood alcohol is not by itself an emergency justifying a warrantless draw
Legal information, not legal advice. Verified as of October 2026. Applying it to a particular situation is the work of a licensed Montana attorney.