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How alcohol affects your ability to drive

Alcohol affects your ability to drive. You are more at risk of being in an accident after you've been drinking.

Even after 1 drink, alcohol affects:

  • reaction times
  • coordination
  • concentration
  • judgement
  • vision

The more alcohol in your system, the more it affects your ability to drive.

If you plan to drive, it's best not to drink at all.

Legal drink-driving limits

Blood Alcohol Concentration (BAC) is a measurement of the amount of alcohol in your blood. It is measured in milligrams of alcohol per 100 millilitres of blood.

The current drink-driving limit is a BAC of 50mg. This means 50 milligrams of alcohol per 100 millilitres of blood.

For professional, learner and novice drivers the limit is a BAC of 20mg.

Most people will have a BAC of 20 to 50mg after 1 standard drink.

Breath testing

Gardaí carry out roadside breath testing for alcohol levels. A breath test measures microgrammes of alcohol per 100 millilitres of breath. The legal limit is 22 microgrammes.

Drinking and driving -

When it's safe to drive again

It takes most people 1 to 2 hours to process 1 standard drink. That means after 3 standard drinks you should wait at least 3 hours before driving.

After you stop drinking, the alcohol levels in your system can continue to rise for up to 3 hours.

Nothing can speed up the absorption of alcohol by your body. For example, drinking water or coffee, eating or having a shower. These will not make the alcohol in your blood disappear any faster. Only time can do that.

Driving, medicines and illegal drugs

Legal and illegal drugs can affect your ability to drive. They can also increase the effects of alcohol.

If you are taking medicine, read the information leaflet or ask a pharmacist or GP if it's safe to drive. If in doubt, do not drive.

Take your medicines in accordance with your GP or pharmacist's advice and guidance. Taking your medicines is important to maintain your health for driving.

Driving under the influence of any drug is illegal in Ireland. The Gardaí now conduct roadside drug testing.

Drug interactions with alcohol

Drug driving laws in Ireland -

Safety tips

To help keep you safe on a night out:

  • have a designated driver
  • find out about public transport options before you go out
  • budget for a taxi
  • have a backup plan for getting home – a friend or parent you can call
  • arrange to be picked up
  • arrange to stay overnight
  • do not accept a lift from someone who has been drinking

Use our drinks calculator to find out how your drinking affects your health, money and weight.

Page last reviewed: 23 September 2022
Next review due: 23 September 2025