Alcohol and road safety

Alcohol is a major factor in road deaths and serious injuries in Victoria. Each year about 20 per cent of drivers killed in road crashes had a Blood Alcohol Concentration (BAC) of .05 or greater.

What can increase your BAC?

Other than alcohol, some medications will actually increase your BAC and some ingredients in chocolates, cough lollies and mouthwashes may cause a mouth alcohol reading when breath tested.

BAC limits and alcohol testing

BAC is a measure of how much alcohol is in your body.

If you are a restricted motorcycle rider or a learner, probationary or professional driver (e.g. a truck, bus or taxi driver), you must drive with a zero BAC.

Other drivers and those supervising learner drivers, must drive with a BAC under .05.

These laws apply if you are on private property or a public road, where you may be stopped for alcohol testing. 

Refusing to provide a sample

It is a serious offence to not:

  • provide a breath or blood sample
  • stop at a booze bus or random breath testing station, or
  • cooperate with police who are trying to carry out a breath or blood test.

To find out about the penalties that apply for refusing a test, visit drink-driving penalties

The laws regarding driving with alcohol and drugs are published in the Road Safety Act 1986 (External link). Please refer to Part 5 - Offences involving alcohol or other drugs.

Driving is a complex task requiring concentration, judgement and decision making. Alcohol affects these skills and decreases a driver’s ability to safely control their vehicle. 

At a BAC of .05, your risk of being involved in a road crash is about double compared with a BAC of zero. 

Drink-driving statistics from TAC indicate that the vast majority (99.7 per cent) of drivers tested do not exceed their legal blood alcohol levels. However in the last five years, around one in five drivers and riders who lost their lives had a BAC greater than .05.

Alcohol is a depressant that: 

  • slows your brain so that you can’t respond to situations, make decisions or react quickly
  • reduces your ability to judge how fast you are moving or your distance from other cars, people or objects
  • gives you a false sense of confidence - you may take more risks, thinking that your driving is better than it really is
  • makes it harder to multi-task – while you concentrate on steering, you may miss seeing traffic lights, passengers or cars entering from side streets 
  • affects your sense of balance – a huge risk if you ride a motorcycle
  • makes you drowsy – you could fall asleep at the wheel.

If you have been drinking, allow plenty of time for the alcohol in your bloodstream to reduce before driving. Cold showers, exercise, black coffee, fresh air or vomiting do not help.

Please note that if you have drunk a lot of alcohol the night before you are still likely to be over the legal limit the next day, or hungover. You should rethink driving or using heavy machinery the next day, especially if you are a learner or probationary driver, or a professional driver on zero BAC. A hangover will make you feel unwell and tired, and is another reason why you shouldn't drive the next day.

If you know that you need to drive the next day, make the decision to not drink the night before.

Two people, who drink the same amount of alcohol, can register different BACs. 

This is because:

  • a smaller person will have a higher BAC than a larger person
  • a person with a lot of body fat tends to have a higher BAC
  • a woman will almost always have a higher BAC than a man of similar size who drinks the same amount.

As there’s no easy way to know that you are okay to drive after drinking, the only way to be sure is to not drink alcohol if you are going to drive.

Coin operated and commercially available breath testing units that measure BAC can be used as a guide but should not be relied on because they can be inaccurate and can’t be used as evidence in case of a drink-driving charge. So, it’s best to completely separate your drinking from driving.

Don’t drink alcohol when you’re taking other drugs as small amounts of alcohol combined with drugs or medications can reduce your ability to drive safely.

This applies to medicines prescribed by your doctor, bought in a supermarket or pharmacy, or illicit drugs such as cannabis and speed.

Mixing alcohol with energy drinks is dangerous. Energy drinks can mask the effects of alcohol as the caffeine makes you feel more alert, and you may be drunk without realising it. 

Never drive if you’ve had alcohol mixed with drugs, medicines or stimulants. Always plan ahead and use other ways to get home safe; you may need a plan B if plan A doesn't work.

The safest option is if you are going to drink, don’t drive, or if you are going to drive, don’t drink. 

You can avoid drink-driving by planning ahead:

  • designate a non-drinking driver
  • hire a taxi or ride share
  • 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
  • always have a plan B if plan A goes amiss.

You must not drink alcohol, even if your blood alcohol concentration stays below your legal limit, while:

  • driving a motor vehicle
  • sitting beside a person who is learning to drive.

Failure to comply may result in a fine of up to ten penalty units, or if you receive an infringement notice, the penalty is two penalty units.

This is an offence even if you are under the legal limit.

Passengers are not prohibited from drinking alcohol in a vehicle. However, it is advised that passengers do not engage in drinking as drunk passengers could distract a driver.

For more information, visit drink-driving penalties.

An alcohol interlock stops you from starting your vehicle if you have been drinking. You need to blow into the interlock every time you start your vehicle and at different times during the trip.

In Victoria, alcohol interlocks are fitted to vehicles of drivers who have been convicted of a drink-driving offence.

For more information about alcohol interlocks, visit drink-driving offences & alcohol interlocks.

An alcohol interlock stops you from starting your vehicle if you have been drinking. You need to blow into the interlock every time you start your vehicle and at different times during the trip.

In Victoria, alcohol interlocks are fitted to vehicles of drivers who have been convicted of some drink driving offences.

For more information about alcohol interlocks visit our drink-driving offences page.

Information for participants on the Victorian Alcohol Interlock Program

Guidelines and rules for participants on the program differ depending on:

  • when the drink-driving offence was committed (before, on or after 1 October 2014)
  • whether it was a first offence
  • the Blood Alcohol Concentration (BAC) reading (BAC less than 0.1/BAC of 0.1 or more)

To find out more about what each type of participant is required to do to complete the Program, visit Alcohol Interlock Program participant guidelines

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