Yes, police officers can search a car if they say they smell drugs. And, it doesn’t take a dog!
First, the US Supreme Court ruled in the 1981 case of New York v. Belton that when an officer has reasonable suspicion that a person is committing a crime, they are legally allowed to search any area within the person’s immediate reach and control.
Also, the North Carolina Supreme Court has long held that the smell of marijuana alone is sufficient to provide probable cause for a search. Such a search could be broader than one based on reasonable suspicion, because it could include any place in the vehicle where marijuana could be located. See State v. Greenwood (1981). The doctrine is called the “plain smell” test.
In addition to marijuana, the plain smell test has also been applied to both cocaine and heroin in North Carolina, as the North Carolina Court of Appeals observed in State v. Parker (2022). Apparently, heroin may smell like vinegar?!
When searches can be challenged successfully, evidence uncovered during the search may be suppressed. However, if consent to a search is given by the owner or driver of a vehicle, the search cannot be challenged.