The Tipperary Town to Dundrum Rd is closed following an overnight crash.
The incident occurred on the R661 on the Tipperary town side of Alleen Cross at around midnight.
It was a single vehicle incident – with the occupant of the car believed to be seriously injured.
Collision investigators are en route to the scene, with the road expected to be closed until around 11am.
Gardaí are advising motorists to avoid the area if possible, and are asking trucks travelling on the route to turn off for Donaskeagh at the Rossmore roundabout exiting Tipperary town.