A resident contacted South Simcoe Police shortly after 7 on Saturday morning to report an unknown vehicle parked in their driveway.
Police spoke to the motorist who could not explain why she was parked where she was.
The 39-year-old Barrie woman was arrested and taken to the police station for a breath test.
She was charged with two impaired driving-related offences.
Her vehicle was impounded for seven days, and her licence was suspended for three months.