Barrie police say officers on patrol downtown just before midnight on Wednesday noticed two men walking north on Clapperton Street near Dunlop Street East who looked unsteady on their feet.
Police watched as one guy got behind the wheel of an idling parked vehicle, while the other hopped in the passenger seat.
A quick licence plate check showed the owner's driver's licence had recently expired.
When officers approached, police say they found several open alcohol containers in the back seat and open cannabis packages near the centre console. It's alleged the driver admitted to have "a few" drinks, as officers noted his slurred speech and glossy eyes.
He was arrested and taken to police headquarters, where breath tests showed he was twice the legal alcohol limit.
A 36-year-old from Barrie faces impaired driving charges.
