Alcohol and drugs limits

Alcohol and drugs, including some drugs given to you by a doctor, can seriously affect your driving. They can slow your reaction times and affect your senses.

You risk causing death and serious injury to yourself and other people if you drive under the influence of alcohol or drugs.

Legal alcohol limits for driving

The law says you must not drive if the amount of alcohol in your blood or breath exceeds certain age-related limits.

Under 20

There’s a zero alcohol limit if you’re under 20. That means if you drive after consuming even one drink you can be charged with drink-driving.

  • If you have an alcohol level of less than 150 micrograms per litre of breath, or less than 30 milligrams per 100 millilitres of blood, you could be fined and given 50 demerit points.
  • If your alcohol level is higher, you could be disqualified from driving, given 50 demerit points and either fined or imprisoned.

Twenty or over

You must not drive if you have more than 250 micrograms of alcohol per litre of breath, or more than 50 milligrams of alcohol per 100 millilitres of blood.

  • If you have an alcohol level between 251 and 400 micrograms per litre of breath, or between 51 and 80 milligrams per 100 millilitres of blood, you could be fined and given 50 demerit points.
  • If your alcohol level is higher, you could be disqualified from driving and either fined or imprisoned.

It’s hard to say how many alcoholic drinks you can have before you reach these limits. It depends on many things, including:

  • your gender
  • your size
  • how much food you’ve eaten.

Because even small amounts of alcohol can affect your driving, the best advice is: if you drink at all, don’t drive.

Drugs and driving

The law also says you must not drive if you’ve taken any type of drug that may affect your driving ability. If you’re prescribed drugs by a doctor, always ask if they will have any effect on your driving.

Testing for alcohol and drugs

You can be stopped by the police and tested at any time for alcohol and drugs. The police can use these tests to see if you’ve been drinking or taking drugs. In 2023, random saliva based roadside testing for driving under the influence of drugs will be introduced.

Passive breath test

The police officer will ask you to talk into a hand-held device in front of your mouth. This will show if you’ve recently drunk any alcohol. If any alcohol is detected, a breath screening test will be required.

Breath screening test

The police officer will give you a small electronic device, and ask you to blow into it. If your alcohol level is high, you’ll be asked to take an evidential breath test or have a blood test.

Evidential breath test

This is an electronic device you blow into, which gives a reading that can be used in court as evidence of your breath–alcohol concentration.

Blood test

If you have a blood test, a medical doctor or other approved person will take a sample of your blood to be tested for alcohol or drugs.

Compulsory impairment test

This includes an eye assessment, a walk and turn, and a one leg stand assessment.

If you fail you may be forbidden to drive and required to have a blood test.

Alcohol and drug limits