LANSING – Seven years after Michigan voters legalized recreational marijuana, the state’s highest court has finally answered one of the biggest unanswered questions facing police officers and cannabis consumers.

In a landmark decision, the Michigan Supreme Court ruled that the smell of marijuana alone is no longer enough to give police probable cause to search a vehicle without a warrant. The court said legalization fundamentally changed the legal landscape because the odor of marijuana no longer automatically suggests criminal activity.

The ruling overturns more than two decades of Michigan legal precedent that allowed officers to search vehicles solely because they smelled marijuana.

For Michigan’s estimated millions of adult cannabis consumers, the decision significantly strengthens Fourth Amendment protections during traffic stops. For law enforcement, it means officers must identify additional evidence suggesting criminal activity before conducting a warrantless vehicle search.

What The Ruling Does — And Doesn’t Do

Police cannot search your vehicle solely because they smell marijuana.

Police can search if:

  • Marijuana odor is combined with other evidence suggesting criminal activity.
  • They obtain a warrant.
  • Another recognized exception to the warrant requirement applies.
  • They develop probable cause that a driver is impaired or another crime is occurring.

The decision does not legalize impaired driving or prevent officers from investigating suspected intoxicated drivers.

A 25-Year-Old Rule No Longer Fits Legal Cannabis

The case centered on People v. Armstrong, but its roots stretch back to a 2000 Michigan Supreme Court decision known as People v. Kazmierczak.

In Kazmierczak, marijuana possession was illegal in Michigan. The court ruled that the smell of marijuana alone created probable cause because the odor itself suggested a crime was being committed.

That legal framework changed dramatically after Michigan voters approved the Michigan Regulation and Taxation of Marihuana Act (MRTMA) in 2018, legalizing possession and personal use of cannabis for adults 21 and older.

Justice Megan Cavanagh, writing for the majority, concluded that because marijuana possession is now generally legal, its odor no longer automatically indicates criminal conduct. Instead, marijuana odor is only one factor officers may consider when determining whether probable cause exists.

The Case Behind The Decision

The case arose after officers approached a parked Jeep and reported smelling burnt marijuana.

Prosecutors argued that odor alone justified searching the vehicle under the automobile exception to the Fourth Amendment.

The trial court disagreed, suppressing evidence discovered during the search. The Michigan Court of Appeals affirmed that ruling.

Now the Michigan Supreme Court has done the same, holding that the legalization of recreational marijuana superseded the court’s earlier 2000 decision.

The court emphasized that while marijuana odor remains relevant, it cannot by itself establish probable cause for a warrantless vehicle search.

What Police Can Still Do

The decision does not prohibit police from investigating suspected impaired driving.

If officers observe signs that a driver is under the influence—such as erratic driving, slurred speech, bloodshot eyes, failed field sobriety tests or other evidence—they may still investigate and potentially search a vehicle if sufficient probable cause develops.

Likewise, marijuana odor combined with other evidence suggesting illegal activity could still justify a search.

The ruling simply says smell alone is no longer enough.

Why This Matters Beyond Cannabis

Legal experts say the decision reinforces an important constitutional principle.

Probable cause exists only when officers have a fair probability that evidence of a crime will be found. Once marijuana became legal for most adults, its smell lost much of its value as evidence that a crime had occurred.

Michigan now joins a growing number of states with legal recreational marijuana that have concluded cannabis odor alone cannot justify warrantless vehicle searches.

Potential Impact On Future Cases

Defense attorneys are expected to cite the ruling in future suppression motions involving traffic stops.

Police agencies across Michigan will likely update officer training and search procedures to reflect the new constitutional standard.

The decision also provides greater clarity for millions of Michigan residents who legally possess cannabis under state law.