Can Police Search a Car for the Smell of Weed in Michigan? Only for a Crime

Michigan has no odor statute. It didn’t need one. In less than a year and a half the Michigan Supreme Court decided two cases that took the smell of marijuana out of the automobile exception — and the second one, from this July, catches a search a lot of officers still think is good.

Can Police Search a Car for the Smell of Weed in Michigan? Only for a Crime

No. The smell of marijuana, standing alone, is no longer probable cause to search a vehicle in Michigan (People v. Armstrong, Mich. S. Ct. No. 165233, Apr. 2, 2025). And you need probable cause that the car holds evidence of a crime — probable cause of a civil infraction is not enough (People v. Wilkins, Mich. S. Ct. No. 167737, July 22, 2026).

Michigan: odor and the car — Odor alone is out. And since July 2026, probable cause has to point to a crime. — Michigan: odor and the car — the statute, the controlling cases, and what still gets you into the car. The full breakdown lives inside StreetSense, offline.

Armstrong — odor is a factor, not the answer

The Court held that the old Kazmierczak rule — “that the smell of marijuana, standing alone, is sufficient to support a finding of probable cause under the automobile exception” — “is no longer viable in light of the enactment of the MRTMA.”
It adopted the Court of Appeals’ rule: the smell “may be a factor, but not a stand-alone one, in determining whether the totality of the circumstances established probable cause.”
5–1, opinion amended June 3, 2025. It rests on the Fourth Amendment only; the state constitution wasn’t raised.

Wilkins — probable cause of what?

“A police officer must have probable cause to believe an automobile contains evidence of possession of a criminal amount of marijuana or another criminal offense to conduct a warrantless search under the automobile exception. The smell of marijuana is not enough.”
“Substances prohibited only by civil law are not ‘contraband’ for purposes of supporting a warrantless search.” Where the trooper had probable cause of only a civil infraction, the search was not permissible.
The facts: odor, both occupants under 21, and a passenger admitting to a small amount. For an 18-to-20-year-old, 2.5 ounces or less is a civil infraction on a first offense, fine up to $100 (MCL 333.27965(3)). The search was not permissible.
What still works, per the Court: probable cause of driving under the influence of marijuana, or of distribution of criminal quantities. The Court’s examples of facts that can complete probable cause include a criminal amount in plain view, the defendant smoking, dissipating smoke, and signs of intoxication.
5–2, Fourth Amendment majority; a concurrence would have rested on the Michigan Constitution. It was decided two months ago — check for rehearing activity before you rely on the details.

Still open in Michigan

Reasonable suspicion. Armstrong assumed without deciding that odor could support reasonable suspicion, and left the question open. No answer here either way.
Burnt versus raw. Armstrong declined to draw that line. Don’t assume Illinois’s raw/burnt split applies in Michigan.
Under-21 occupants don’t travel. Maryland’s Appellate Court reached a different result under Maryland’s statute. Michigan’s rule is Wilkins.

How much is legal, and in the car

The MRTMA: adults 21 and over may possess 2.5 ounces, no more than 15 grams of it concentrate; 10 ounces and 12 plants at home (MCL 333.27955(1)). That conduct is “not grounds for search or inspection.”
Over the limit: more than 2.5 up to 5 ounces is a civil infraction, up to $500 on a first violation. More than 5 ounces is a misdemeanor, with no jail unless the violation was habitual, willful and commercial, or involved violence (MCL 333.27965).
The act does not authorize operating a vehicle under the influence, consuming while operating, or smoking in the passenger area of a vehicle on a public way (MCL 333.27954(1)(a), (g)).

The federal floor — and why it doesn't decide your case

Under the Fourth Amendment the automobile exception needs probable cause and nothing more (Maryland v. Dyson, 527 U.S. 465 (1999)), and marijuana is still illegal under federal law.
Armstrong and Wilkins are the Michigan Supreme Court’s reading of the Fourth Amendment. They control Michigan courts; federal courts are not bound by them.
That is the floor. A state court applying its own statute or constitution can — and here does — suppress what a federal court would admit. Work to your state’s rule.

How it plays out on the street

Traffic stop, two 19-year-olds, car smells of marijuana, the passenger says there’s a little bit in her purse. That’s Wilkins, and it’s not a search. A small amount for an under-21 person is a civil infraction, and civil-infraction marijuana isn’t contraband for the automobile exception. Write the infraction. If the driving and your observations point to impairment, investigate OWI on those facts. If you see a criminal amount in plain view, you’re in a different case. Document what you saw, not what you smelled.

Frequently asked questions

Can police search your car for the smell of weed in Michigan?

Not on the smell alone. In People v. Armstrong (2025) the Michigan Supreme Court held that the smell of marijuana is a factor but not a stand-alone basis for probable cause to search a vehicle. In People v. Wilkins (2026) it held that the probable cause must point to a criminal amount of marijuana or another criminal offense.

Can police search a car in Michigan if someone under 21 has weed?

Not on that basis. In People v. Wilkins (July 22, 2026) the Michigan Supreme Court held that where the trooper had probable cause only of a civil infraction, such as under-21 possession of a small amount, the automobile-exception search was not permissible.

How much weed can you have in Michigan?

Adults 21 and over may possess up to 2.5 ounces, of which no more than 15 grams may be concentrate, and up to 10 ounces and 12 plants at home (MCL 333.27955). More than 2.5 up to 5 ounces is a civil infraction on a first violation.

Carry the rule, not the guesswork. StreetSense breaks down Michigan law like this — the statute, the limit, and the charge that actually sticks — verified against the code and available fully offline on shift. Start the free trial.

StreetSense is an educational reference for law enforcement, not legal advice. State law changes, and your department policy may be stricter than the statute. Always follow your state’s current rule and your agency’s policy.

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