Police say a mother who came to pick up her son after he was arrested on suspicion of drunk driving found herself charged with the same offence.

Police say it started when an officer pulled over a speeding vehicle in Innisfil, south of Barrie, just before 1 a.m. Sunday.

Investigators say the driver, a 27-year-old Newmarket man, failed a roadside screening test and was taken to a police station, where he was charged with impaired driving.

When his 53-year-old mother came to retrieve him a few hours later, the same officer smelled alcohol on her and made her take a breathalyzer test.

Investigators say she failed the test and has been charged with impaired driving.

Both mother and son have had their vehicles impounded and licences suspended for 90 days. They are due in court next month.