The head of the Road Safety Authority has appealed to motorists to redouble their efforts to stay safe on the country's roads, especially during the Christmas period.

Noel Brett was speaking after a two people were killed in a road accident in Co Mayo last night.

They were 40-year-old Sandra Herbert, who worked at the Road Safety Authority Headquarters in Ballina, and her 14-year-old daughter Rachel.

They were fom Knockmore in the county.

They were travelling to a local disco, along with three other teenage girls, when the car left to the road and entered a small stream at Cloghans, 5km from Ballina.

Two of the surviving passengers are 14-years-old and the other is aged 13; the three were friends of the teenage girl who died.

The girls raised the alarm following the accident and are currently being treated in hospital.

Mr Brett said Sandra's co-workers held a service in the office to remember her and her daughter.

The road is currently closed due to an ongoing forensic examination by the gardaí.

Separately, the 28-year-old man killed in a single-vehicle collision in Co Waterford yesterday has been named as Brian Walsh from Collins Avenue in Waterford city.

The incident occurred shortly before 9am at Corbally More, between Tramore and Dunmore East.

These latest tragic deaths bring the number of people who have lost their lives in accidents on roads in the Republic so far this year to 175. This compares with 212 for the same period last year.