Ten people have now died on Ireland's roads this week.
The latest crash, near Letterkenny in Co. Donegal, claimed the lives of three people overnight.
Ahead of the Bank Holiday weekend, Clare Gardaí are warning that they'll be out in force.
Gardaí believe speed was a factor in the fatal road crash in Donegal early this morning.
Two men and a woman died when their car crashed in an area known as Corravaddy outside Letterkenny.
Another man has been seriously injured and is being treated at Letterkenny University Hospital.
Garda Inspector Michael Harrison says the people in the two cars may have known each other.
Two people died in another accident near Letterkenny yesterday, while other fatal accidents this week have occurred in Meath, Kildare and Galway.
CEO of the Road Safety Authority Moyagh Murdock says the recent increase is concerning.
