A new survey has revealed that 35% of Irish drinkers admit to driving under the influence, with 66% of them driving the morning after being intoxicated.
Of the 65% of people surveyed who did not drink and drive, 52% still admitted driving the morning after a night out.
Some 83% are unaware of how much they can drink before they get behind the wheel.
The questionnaire was conducted at Ushers Quay Service Station in Dublin on 1,183 motorists for Alcologic Personal Breathalyser to show the real danger of drink driving.
Recent statistics published by the HSE found one in three crashes between 2003 and 2005 were alcohol-related.
With one in six people arrested for drink driving last year caught in the morning time, Alcologic said the results show the benefit of having a personal breathalyser.
A spokesman said the legal alcohol limit for driving in Ireland is 0.08% blood alcohol content, but many factors can affect the rate at which alcohol is absorbed by the body including age, weight, sex and even altitude.