Just one glass of wine or a pint of beer could put you over the drink-driving limit, motorists have been warned.
The gardai and Road Safety Authority launched their Christmas and New Year safety appeal today and are pleading with people not to drink and drive.
Professor Denis Cusack, Director of the Medical Bureau of Road Safety, said that while he wants people to enjoy the festive season, drink-driving can have devastating consequences.
Speaking on RTE Radio One's Morning Ireland, he said: "If you've been out drinking until two or three in the morning, there's a big risk, particularly if you're a learner driver or a novice driver where the limit is 20 (20 mls of alcohol per 100mls of blood), not only of being caught but also of being in an accident and causing injury or killing somebody.
"One pint of beer or one glass of wine could put you over the limit, especially novice or professional drivers where the limit is 20/100."
He added that it is difficult for people to work out if they may be over the limit or how alcohol may impair their ability to drive, so he is urging people not to get behind the wheel if they have been drinking.
"The human body is a fantastic machine, it has to work in a certain way, so when we take in a drink, we've got to handle it in the body and then get rid of it.
"One of the difficulties is you've almost got to be an expert in alcohol because beer, wine, spirits, liquors, they all have different alcohol concentrations.
"How much you drink, how quickly you drink it, whether you mix beer and spirits, whether you've had a meal, your weight, your obesity, fat cells, also whether you've taken food with it, and indeed, how used you are to taking alcohol. All of these go together.
"The advice really is, the bottom line is, don't drink and drive. It's very, very difficult to estimate how much is in your body," Professor Cusack said.
Experts are also warning about the dangers of driving the morning after drinking alcohol - new figures show that 11per cent of fatal collisions in which a driver had consumed alcohol happened between 7am and 11am.
Garda statistics indicate that 6pc of all Driving Under the Influence arrests this year happened between 7am and 11am, with the highest pc of these happening on Sunday mornings.
Professor Cusack also noted that it is important to remember that you may still be over the drink-driving limit the morning after.
He explained: "Our bodies can only handle and get rid of alcohol, we get rid of approximately half a pint or a glass of wine every hour. So if you take two pints it's going to take four hours to get rid of that from your system.
"It takes an hour to get most drinks from your system. However, people rarely keep tabs on how much they've been drinking, when you keep on adding every 15 minutes, half an hour, it's impossible to calculate.
"The bottom line is, don’t drink and drive."
Transport Minister Shane Ross echoed these sentiments at the appeal's launch today, saying drink-driving can cost lives.
"The focus of our appeal this year is to warn the public about the dangers of driving the morning after consuming alcohol.
"We know that alcohol remains a significant contributory factor in fatal crashes and is responsible for far too many deaths and injuries on Irish roads.
"I appeal to all those socialising over the Christmas and New Year period to do so responsibly and never, ever, drink and drive, including the morning after," Minister Ross said.
"It’s simply not worth the risk now that new penalties have been introduced which mean drivers detected with a blood alcohol concentration between 50mg and 80mg face losing their licence for three months.
"So if you have done the right thing the night before, don’t forget to do the right thing and make alternative arrangements to travel the morning after."
RSA Chairperson Liz O'Donnell reiterated the importance of not being over-the-limit the morning after the night before.
She said: "Drink driving at any time of the day or day of the week is drink driving, which is why you must take extra care the following morning if you have been drinking the night before.
"If you have been on a drinking session the night before and got to bed very late you could still have alcohol in your system."