Same DUI arrest, two very different tests. Birchfield v. North Dakota draws a hard line between blowing into a tube and putting a needle in an arm — and it changes what you can demand without a warrant.
What did Birchfield v. North Dakota decide?
As a search incident to a lawful DUI arrest, police may administer a warrantless breath test, but a warrantless blood test is not permitted — a blood draw requires a warrant or a valid exception. A state may not make it a crime to refuse a warrantless blood test, though it may penalize refusal of a lawful breath test.
Birchfield v. North Dakota, 579 U.S. 438 (2016) — read the opinion on CourtListener.
What does Birchfield v. North Dakota allow?
- A warrantless breath test as a search incident to a lawful DUI arrest
- Criminal or administrative penalties for refusing a lawful breath test
- A blood draw when you have a warrant or a recognized exception (such as true exigency)
What does it NOT allow?
- A warrantless blood draw justified as ‘search incident to arrest’
- Criminalizing a driver’s refusal of a warrantless blood test
How it plays out on the street
Breath is generally fair game incident to a lawful arrest; blood means get a warrant unless a real exception applies. Whether — and how — you can penalize a refusal depends on which test it was and your state’s implied-consent statute. This is the federal floor, and states structure DUI testing and refusal penalties very differently, so know your own code (for unconscious drivers, see also Mitchell v. Wisconsin).
Frequently asked questions
Do I need a warrant for a breath test on a DUI arrest?
No. Birchfield allows a warrantless breath test as a search incident to a lawful DUI arrest.
Do I need a warrant for a blood draw?
Yes, unless a valid exception such as exigency applies. A warrantless blood draw cannot be justified as a search incident to arrest under Birchfield.
Related cases
- NJ DWI Laws: A Patrol Officer’s Field Reference
- U.S. v. Robinson (1973): How Far a Search Goes After Arrest
- Arizona v. Gant (2009): Can Police Search Your Car After Arrest?
Carry the rule, not the guesswork. Every case in StreetSense is broken down like this — bottom line, limits, and the exact citation — verified against the real opinion and available fully offline on shift. Start the free trial.
StreetSense is an educational reference for law enforcement, not legal advice. Federal cases set the floor — your state constitution, statutes, and department policy can impose stricter limits. Always follow your state’s rule and your agency’s policy.