A woman has been arrested on suspicion of drink-driving after an intervention from Garda Commissioner Drew Harris.
The former RUC and PSNI officer was on his way to Garda headquarters around 5:30pm on Tuesday when he saw a car being driven erratically.
RTE has reported that Commissioner Harris then called the Garda's Road Policing Unit who stopped the woman.
She was then arrested and tested for alcohol.
Garda Headquarters has confirmed that the police chief was present at a road traffic incident during which a driver was arrested for an offence.