State v. Mennegar
In State v. Mennegar, 114 Wn.2d 304, 787 P.2d 1347 (1990), officers arrested a person for driving under the influence and impounded his vehicle.
They determined a passenger could drive the vehicle and checked the passenger's driver's license, revealing an outstanding arrest warrant. In a search incident to arrest on the warrant, the officers found drugs.
The Court said:
The question then becomes whether it was reasonable and legal for the officer to request the passenger's driver's license and check to insure that the license was valid before turning the intoxicated driver's vehicle over to the passenger.
Whether such an encounter, made for noncriminal noninvestigatory purposes, is reasonable depends upon a balancing of the individual's interest in freedom from police interference against the public's interest in having the police perform a "community caretaking function". Id. at 313.