Risk perception is one of the study areas behind the driver theory test in Ireland, where the car test asks 40 questions in 45 minutes and 35 correct answers pass. This lesson gives the rules, the law behind them and questions on this area. Source: Citizens Information, page edited 6 May 2026, checked on 15 September 2026.
By the Irish Mock Test teamFacts checked 15 September 2026How we check facts
The general drink driving limits are 50 milligrammes of alcohol per 100 millilitres of blood, 67 milligrammes per 100 millilitres of urine and 22 microgrammes per 100 millilitres of breath.
The specimen is measured within three hours of driving, and these are the limits for a driver who is not a specified person.
Risk perception asks what speed, weather and your own state do to the distance you need in order to stop. Alcohol, drugs, medicines, tiredness and distraction sit here, and so do following distance and road holding. Part of the area is law and part is advice, and every rule below says which it is.
The rules
Drive no faster than lets you stop within the distance you can see to be clear.
The only rule on stopping distance in the instruments read, and it sets no number.
Advice, not law: in dry conditions the Road Safety Authority gives a total minimum stopping distance of 25 metres at 50 km/h, 70 metres at 100 km/h and 102 metres at 120 km/h.
No Irish instrument sets these numbers, so an answer that calls them a legal requirement is wrong even when the figures themselves are right.
The general drink driving limits are 50 milligrammes of alcohol per 100 millilitres of blood, 67 milligrammes per 100 millilitres of urine and 22 microgrammes per 100 millilitres of breath.
The specimen is measured within three hours of driving, and these are the limits for a driver who is not a specified person.
A specified person has lower limits: 20 milligrammes per 100 millilitres of blood, 27 per 100 millilitres of urine and 9 microgrammes per 100 millilitres of breath.
Twenty is not zero, and that is the trap. On the breath figure the official sources disagree, because the Act says 9 microgrammes while a Citizens Information page writes 9mg.
Do not hold a mobile phone while driving. Holding covers supporting or cradling it with any part of your body, and a hands-free device is not a mobile phone for this rule.
The defence is a call to the emergency services or a genuine emergency.
No. The instruments read set a duty and no number: you drive so that you can stop within the distance you can see to be clear. The metres people learn come from the Rules of the Road, where they are advice, so a driver who hits something inside that distance has broken the duty whatever the table says.
What is the drink driving limit for a learner or a novice driver?
Twenty milligrammes of alcohol per 100 millilitres of blood, against 50 for other drivers. The same lower band covers a driver in the first two years after a first full licence, a taxi driver at work, a driver of a truck, bus or work vehicle while driving one, and anyone driving unlicensed.
On the road
Choosing a speed on a wet national road at night
You are on a national road with no lower limit signed, so the default of 100 km/h applies.
It is dark and raining, dipped headlights show clear road for about 60 metres, and oncoming traffic keeps you off full beam.
Article 7 is the test: no faster than lets you stop inside the distance you can see to be clear, which tonight is 60 metres.
Advice puts the dry total stopping distance at 100 km/h at 70 metres, and wet braking takes longer again.
You settle at a speed whose stopping distance fits inside the lit road, and stretch the gap ahead.
Where learners go wrong
Answering that a learner has a zero alcohol limit. The lower limit is 20 milligrammes per 100 millilitres of blood.
Quoting a stopping distance as a legal requirement. The metres are advice; article 7 is the duty.
Bringing in a table in feet and miles per hour from another country. Irish figures are metric.
Thinking a hands-free call breaks the phone rule. What the section bans is holding the phone.
Expecting a drug question to turn on impairment. Being at or above the level set in law is the offence on its own.