Vaughn wasn't cited for any violation after a preliminary breath test showed the actor's blood-alcohol level was below the legal impairment limit of 0.08, Scottsdale police Sgt. Mark Clark said.
"We determined he had something to drink but was not over the legal (impairment) limit," Clark said. "We suggested that he not continue to drive."
Vaughn parked the vehicle, described as a white van or truck, at a nearby resort, Clark said. He said Vaughn and Aniston then got into the car of a friend who had been following them.
Clark didn't have any details on why Vaughn was stopped early Tuesday. Police said the patrolman who pulled over the vehicle smelled alcohol on Vaughn's breath.
Messages left for publicists for Aniston and Vaughn, who co-star in the upcoming film "The Break Up," weren't immediately returned Thursday.
For months, reports have swirled that Vaughn, 35, and Aniston, 36, are dating. Last month, People magazine published photos showing the couple kissing in Chicago, possibly confirming that their relationship has grown romantic.
Aniston was divorced from Brad Pitt last month after 4 1/2 years of marriage.
Vaughn, whose father lives in Phoenix, co-starred earlier this year with Pitt and Angelina Jolie in "Mr. & Mrs. Smith." It was then that reports of a romance between Pitt and Jolie began, which were later corroborated by photographs and public spottings.
"The Break Up" is scheduled for release next year.