NEW Alcohol Interlock Laws come into Force Today: This is How They Work

21 August, 2017

Motorists caught driving with a blood-alcohol reading more than three-times the legal limit, and repeat drink drivers, will need to have an alcohol lock-out system installed in their vehicle.



Drink driving is a factor in around 1 in 5 fatal crashes in WA, and 1 in 10 serious-injury crashes costing the community in excess of $460 million. Approximately 4,000 – 6,000 people commit drink driving offences each year in WA.

The primary purpose of an alcohol interlock scheme is to reduce the road safety risk posed by drink drivers to themselves and other road users.


Who will this apply to?

High end and repeat drink drivers will be required to install an alcohol interlock in their vehicle, if convicted of one of the following offences:

  • Any Driving under the influence of alcohol offence (BAC of 0.15 or more),
  • Any dangerous driving causing death/injury offence where DUI is an element,
  • Any dangerous driving causing bodily harm offence where DUI is an element,
  • Two offences within 5 years having a BAC between 0.05% and 0.149%,
  • Failure to comply with giving a breath sample to WA Police.

So how do they work?

Alcohol interlocks are electronic breath testing devices that can be linked to the ignition system of passenger vehicles, motorcycles and
heavy vehicles. A vehicle with an approved alcohol interlock installed will not start unless the driver passes a breath test.

The driver must provide a breath sample with a blood alcohol content (BAC) below 0.02% BAC before the vehicle will start. Randomly timed breath tests must also be provided and passed during a journey.

Once a person is convicted of one of the above offences, a court will order the person to install an interlock system into their vehicle, at their own expense ($1,600).

An estimated 5000 WA drivers will have the interlock systems installed by court order each year.


How long are offenders bound to use the alcohol interlock system?

There are mandatory minimum periods required of an interlock-restricted driver. The minimum participation periods are:

  • For permanently disqualified alcohol offenders granted an extraordinary licence – three (3) years;
  • For disqualified alcohol offenders granted an extraordinary licence – the duration of the extraordinary licence (unless the extraordinary licence is valid for less than 180 days in which case further requirements will apply); and;
  • For a person who serves his or her period of disqualification and is subsequently granted a driver’s licence – 180 days.

For more detailed information about the alcohol interlock system and requirements to have the interlock condition removed – click here.

With national and international research showing that interlocks are effective in reducing drink driving reoffending (on average by 64%) and reduction of drink driving crashes (of at least 30%), we can look forward to a healthier community and safer roads in Western Australia.


If you have any further questions, please contact our office on (08) 9581 4339. We provide an initial consultation at no cost to discuss your current claim and possible entitlements.  We also act on a no win no fee basis if we are able to assist with your claim. This article should be considered as general legal information and should not be viewed as legal advice.