A 71-year-old woman has become the fifth person to die on the State's roads since last night.
She was crossing the road at Castle Street, Cahir, Co Tipperary at 10.30 a.m. when she was hit by a truck.
Meanwhile, the three teenagers killed in a crash in Co Donegal last night have been named by gardai.
Shane Cuffe (18), Owen Doherty (18), both from Buncrana, and 16-year-old Aine O'Leary, from Skerries, Co Dublin, died when the car they were travelling in hit a bridge and crashed into a tree at Ballymagan, near Buncrana, at around 11 p.m. last night.
The scene of the crash in Donegal
A fourth passenger, a girl aged 16, was taken to Altnagelvin Hospital in Derry. Her injuries are not thought to be life-threatening. The road was closed off and a forensic examination of the scene was due to take place later today.
Gardai believe the three people who died were not wearing seatbelts.
Eight people have been killed in road accidents in the town this year, 22 have died in Co Donegal as a whole.
Father Con McLaughlin, who visited all of the families as the news broke, said it was a terrible tragedy which had left the community stunned.
"Two of these victims live very close to one of two young men who were killed here just a fortnight ago," he said.
"I watched a number of people gathered at the scene in small groups last night in absolute disbelief at such another horrific tragedy.
"You can never get used to seeing their bodies being carried from the twisted wreckage. They were only children. It's a terrible cross for the people of Buncrana to bear."
Gardai have also named the woman who died in a crash near Kilrush, Co Clare yesterday evening. Margaret Haverty (48), from Borrisokane, Nenagh, Co Tipperary, died in a collision with a bus. The bus driver was taken to Ennis General Hospital.