A man in his 20s was killed in the early hours of yesterday morning on the M1 motorway near Donabate, Co Dublin.
He was the back-seat passenger in a car which crashed on the northbound carriageway at about 3.30am. The driver and another passenger were treated in hospital for injuries before being released yesterday.
In another incident three men and two women were injured in a single-vehicle crash at Celbridge at 5.30am.
Gardaí at Naas were also investigating a single-vehicle crash which occurred in Eadestown, Naas, Co Kildare shortly after midnight on Sunday morning.
A 21-year-old male back-seat passenger was seriously injured and was taken to Naas General Hospital where his condition was described as critical.
The driver and front-seat passenger, both youths in their late teens, suffered minor injuries.