A fifth of passengers have admitted travelling in a car with a drunk driver over the last two years, a poll of more than 14,000 people by AA Motor Insurance has revealed.
The survey revealed the figure rose to more than a quarter among 17 to 24-year-olds who took a lift from someone believed to be over the legal limit, while one in 10 in the age group was also driven by someone they suspected of taking drugs.
Conor Faughnan, AA Ireland's director of policy, said: "While as a passenger you may not be breaking the law yourself under these circumstances, you do have a moral responsibility.
"Alcohol is a contributing factor in a third of fatal accidents on our roads and passengers owe it to their own safety and that of other road users not to turn a blind eye or allow convenience to overrule their good sense."
The figures were published just months before the breath test limit for drink driving is lowered to 50mg of alcohol per 100 millilitres of blood, down from 80mg. It will drop to 20mg of alcohol per 100ml of blood for both learners and professional drivers, while roadside tests for people suspected of taking drugs are being devised.
But under the changes being rolled out, some drivers just over the new limits will be given a controversial second chance to keep their licence.
Instead of going through the courts to face an automatic ban, Gardai will be given powers to impose three penalty points and an on-the-spot fine.
The AA survey also revealed that 45% admitted to driving the morning after drinking, despite being unsure whether their blood alcohol levels had returned to legally permissible levels.
More than a third stated they had got into a car with a driver they knew to be nursing a very bad hangover in the last 24 months.
The AA said 10% more men than women - 49.8% compared to 39.7% - have taken this gamble at some point within the last two years.