Alcohol & drink driving

Drinking alcohol affects driving skills and increases the likelihood that the driver will engage in risk-taking behaviour.  You don’t have to be drunk to be affected by alcohol.  You might feel normal, but no one drives as well after drinking alcohol.  Studies have also shown that a driver’s risk of being involved in a casualty crash doubles for every increase of 0.05 above zero BAC. View more on alcohol involvement in road crashes (PDF).

While most of the attention is focused on people who drink and drive, cyclists and pedestrians affected by alcohol also risk being killed or injured on our roads. 

Alcohol has been identified as a significant risk factor in collisions involving a pedestrian with around a quarter of pedestrian fatalities found to have a blood alcohol concentration above the legal driving limit of 0.05.  Over half of those who had been affected by alcohol were found to have a blood alcohol concentration more than 4 times the legal limit. 

Research also shows that a single drink increases the risk of death or serious injury by five times.  Cyclists who are affected by alcohol were also less likely to wear a helmet.  Those who have lost their driver’s licence and switch to cycling as a means of transport may be putting themselves at even greater risk if they continue to drink and use the roads.

Alcohol is a bigger road safety problem than all other drugs combined. 

Allow time to recover

Alcohol affects people differently

Keeping your BAC under .05

Don’t combine alcohol with drugs or other medicines

Tips for getting home safely

Allow time to recover

If you have been drinking, you have to allow time for the alcohol in your bloodstream to reduce before you drive.  Cold showers, exercise, black coffee, fresh air or a big meal do not help to reduce your BAC.

If you have had a heavy night of drinking, you may be over the limit for much of the next day – the more you drink, the more time you must allow.

So, if you are planning to drink, then plan NOT to drive. 

Alcohol affects people differently

The effect of alcohol varies greatly from person to person and is influenced by a variety of factors, including:

  • body size – a smaller person will have a higher BAC than a larger person
  • body fat – people with a lot of body fat tend to have a higher BAC
  • gender – a woman will almost always have a higher BAC than a man who drinks the same amount
  • the length of time since the person has eaten
  • level of fitness
  • the health of their liver
  • whether they drink regularly
  • mood
  • the type of drink consumed
  • the person's efficiency in eliminating alcohol from the body (which may vary from time to time as well as from person to person).
Two people who drink the same amount can register quite different BACs. 

Keeping your BAC under .05

To help you avoid going over the limit try the following:

  • Start with a soft drink or water.
  • Drink light alcoholic drinks.
  • Only have one type of drink.
  • Alternate between alcohol and non-alcoholic drinks.
  • Avoid drinking in rounds.
  • Don’t let people top up your glass.
It is safest not to drink any alcohol at all if you are going to drive. 
Do NOT drive if there is any doubt about your BAC. 

Don’t combine alcohol with drugs or other medicines

Do not drink alcohol when you are taking other drugs.  Even small amounts of alcohol in combination with drugs or medications can reduce your ability to drive.

This applies to medicines prescribed by your doctor, bought in a supermarket or pharmacy.

Tips for getting home safely

If you are going to be drinking, plan an alternative way of getting home, other than driving.  For example:

  • designate a non-drinking driver
  • catch a taxi home
  • use public transport
  • stay the night (make sure you are not still over the limit in the morning!)
  • arrange for someone to pick you up
  • only accept a lift if you are certain the driver has not been drinking or using other drugs.

What the law says

Drink and drug driving penalties strengthened

From 1 February 2010, any person who commits a drink or drug driving offence will face tougher penalties, including:

  • A three month licence disqualification for a first court conviction when:
    • driving with a prescribed drug (including cannabis, speed or ecstasy) present in saliva or blood, or
    • driving with a blood alcohol concentration of 0.05 to 0.079.
  • Heavier penalties for repeat offenders, with courts considering previous drink and drug driving offences during sentencing.
  • An alcohol or drug dependency assessment may be required (depending on the number of previous drink or drug driving offences committed).

For example, if a person has, within the previous five years, expiated or been convicted of one of the following offences they will require an alcohol or drug dependency assessment.

  • Three or more Category 1 offences.
  • Two Category 1 offences and one Category 2 offence.
  • Two or more serious drink driving offences.
  • Two or more drug driving offences.

A blood sample must be taken from any person 10 years or older, who attends or is admitted to hospital for treatment as a result of a boat or motor vehicle accident (previously the minimum age was 14 years). In addition, South Australia Police will now be able to test boat operators for prescribed drugs (including cannabis, speed and ecstasy) under the same conditions as drug testing for vehicle drivers. 

Category 1 drink driving offence - an offence between 0.05 and less than 0.08 BAC
Category 2 drink driving offence - an offence between 0.08 and less than 0.15 BAC 
A serious drink driving offence includes:
Driving under the influence of an intoxicating liquor
Refusing to provide a sample of breath or blood for alcohol testing
Driving with a BAC at or above 0.15
Driving with a BAC at or above 0.08 where a previous alcohol offence exists within the last 5 years.  

Under the Road Traffic Act 1961, it is an offence to:

  • drive with a prescribed concentration of alcohol (PCA)
  • drive under the influence of alcohol or drugs (DUI)
  • refuse to comply with directions from a police officer in relation to an alcotest or breath analysis (Refusal to blow).

Prescribed concentration of alcohol

The prescribed concentration of alcohol (PCA) is the level of blood alcohol concentration (BAC) at, or above which, it is illegal to operate a motor vehicle.  The PCA limit varies, depending on the type of licence held.

A person who drives, or attempts to drive a motor vehicle with more than the 'prescribed concentration' of alcohol in the person's blood is guilty of an offence (s47B(1)).  The severity of the penalties imposed will depend on how much the driver exceeds the prescribed concentration of alcohol.

The PCA for holders of an unconditional licence or qualified supervising drivers accompanying a learner driver is 0.05 BAC.

The PCA for learner, provisional and probationary drivers, as well as drivers of buses, taxis, heavy vehicles and vehicles carrying dangerous goods is ZERO.

Where learner, provisional and probationary drivers are caught driving with a BAC greater than zero, they may be charged with both breaching their licence conditions and the offence of driving with the prescribed concentration of alcohol.

“Drivers and riders can be stopped at random by any police officer at any time, anywhere in South Australia, and tested for alcohol as well as prescribed drugs.  This includes passengers acting as a qualified supervising driver for a learner driver”.

Driving under the influence

A person who drives, or attempts to drive a motor vehicle while so much under the influence of an intoxicating liquor or drug (either prescription or illicit) as to be incapable of exercising effective control of the vehicle is guilty of an offence (s47(1)).

Driving under the influence, more commonly referred to as DUI, is not the same as driving with the prescribed concentration of alcohol.  Even if your BAC is less than 0.05, you may still be charged with DUI if your driving ability is impaired because of the effects of alcohol or other drugs.  Factors that are likely to contribute towards this offence are the manner in which the vehicle was being driven and any signs of intoxication (including observations by the police and other witnesses), the smell of alcohol about the driver, unsteadiness, watery or bloodshot eyes and slow or slurred speech.

Refuse to blow

It is an offence to refuse, or to fail to comply with, a direction of a police officer in relation to an alcotest or breath analysis (s47E(3)).

Alcohol Interlock Scheme

Mandatory Alcohol Interlock Scheme

From 1 May 2009, a mandatory Alcohol Interlock Scheme will operate in South Australia. Information about the mandatory Scheme and how it operates is available here.

Voluntary Alcohol Interlock Scheme

The existing voluntary Alcohol Interlock Scheme will be phased out over a period of five years and transitional arrangements have been made for current participants so they can complete their time on the program.

An alcohol interlock device is fitted to a motor vehicle to monitor a driver’s BAC preventing the vehicle from being started or operated if the driver’s BAC exceeds a zero reading. 


The Mandatory Alcohol Interlock Scheme brochure (PDF)

Alcohol - information

Blood Alcohol Concentration - information


Motor Accident Commission - Drink Driving campaign

Drug and Alcohol Services South Australia

Alcohol Interlock Scheme

The Law Handbook

Road Traffic Act 1961

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