More than 500 people were arrested for suspected drink driving offences over the bank holiday weekend, according to gardaí.
Chief Superintendent Gabriel McIntyre said almost 2,000 checkpoints were used over the weekend and that a number of people were also arrested for suspected dangerous driving offences.
He said a “small number” of motorists were arrested for suspected drug driving offences.
The majority of arrests took place during the “11pm to 3am” periods he said, adding that very few drivers were arrested at checkpoints later in the morning.
While five people had been killed over the Bank Holiday – two more than the same period last year – he said the overall number killed so far this year at 196 was 42 less than in 2008 and described this as evidence of a change in mentality by motorists.
Supt McIntyre appealed to motorists to drive defensively and to pay attention to vulnerable road users such as pedestrians and cyclists, particularly as during the dark, winter evenings. He noted that two pedestrians were among those killed over the weekend.
The first of the four fatalities came at about 2pm on Saturday when a 61-year-old man was struck by a car at Roxboro Road.
In the early hours of yesterday morning, two cars were involved in a collision at Caherulton, Castlemartyr, Co Cork, resulting in the deaths of two men and injuries to two women.
A man died when his van left the road and plunged 150 feet into the Atlantic on Achill Island, Co Mayo.
Last night an 81-year-old woman was killed when she was struck by a car on the Malahide Road in Coolock in Dublin shortly after 6pm.
Separately the AA said a survey it conducted over the weekend shows a rise in support for reducing the drink-driving limit.
Between Friday last and Monday, 7,000 motorists were asked for their views on the proposal, contained in the draft Road Traffic Bill, to reduce the blood alcohol content limit from 80mg to 50mg per 100ml of blood.
A total of 49.8 per cent said they were “completely in favour” of the policy and 14.1 per cent said they were “somewhat in favour”.
Combining those two groups, AA spokesman Conor Faughnan said 63.9 per cent “are in favour of reducing the alcohol limit to 50mg, an increase of almost 3 per cent on the 61.1 per cent approval rate when a similar poll was conducted last year”.
He said 27.9 per cent of respondents were opposed to the proposed change, with 16 per cent “completely against” and 11.9 per cent “somewhat against”.
Mr Faughnan said the figures showed support for the measure was “reasonably uniform” across the country. It was strongest in Dublin, with 66.3 per cent approval, and weakest in Cork, where there was 58.1 per cent approval.
The data also showed that support was stronger among women (71.5 per cent) than men (62.9 per cent) and that over-65s were more in favour of the proposal than any other age group.
“It is abundantly clear that Irish motorists understand the drink-driving issue and want to see the limit lowered into line with limits elsewhere in Europe and beyond,” Mr Faughnan said. He added that the poll results would “come as encouragement” to Minister for Transport Noel Dempsey.