News · Criminal law explainer
The mandatory alcohol interlock program in NSW.
For most drink-driving offences in New South Wales, the mandatory alcohol interlock program is now a central part of the penalty. It changes the shape of a disqualification and can get a driver back on the road sooner. This note explains how the program works, who it applies to, and when an interlock exemption is granted instead.
By Aaron Kernaghan · Published 3 September 2026
The mandatory alcohol interlock program applies to most drink-driving offences in NSW, including high-range PCA and repeat offences. After a shorter disqualification, the driver moves to an interlock licence and must drive a vehicle fitted with a device that requires a zero alcohol reading to start it, for a set period. It gets drivers back on the road sooner than a straight disqualification, and an exemption is only for limited cases.
What is the interlock program?
The mandatory alcohol interlock program requires certain drink-driving offenders, after a shorter period of full disqualification, to drive only a vehicle fitted with an approved alcohol interlock device. The device is connected to the ignition, and the vehicle will not start unless the driver provides a breath sample with a zero alcohol reading.
The program combines a period off the road entirely with a longer period back on the road but under the control of the device. It is designed to separate drinking from driving.
Who does it apply to?
The program applies to a defined list of alcohol PCA offences, including high-range PCA, mid-range PCA in some cases, repeat offences, and offences involving refusing a breath analysis or driving under the influence. For these offences, an interlock order is the default outcome.
For the offences it covers, the court makes an interlock order unless it grants an exemption. So for most serious and repeat drink-driving offences, the interlock is the expected path.
How the disqualification works with the interlock
Under an interlock order, the disqualification period is shorter than a straight disqualification would be, and it is followed by a minimum period on an interlock licence. For a first high-range PCA, for example, the disqualification is a minimum of 6 months and a maximum of 9 months, then the interlock period.
So the total time under restriction is longer, but the time completely off the road is shorter. For most drivers, being able to drive on an interlock licence is far better than a long straight disqualification.
When is an interlock exemption granted?
A driver can apply for an interlock exemption, but it is only granted in limited cases, such as where the person does not have access to a vehicle to fit a device, or has a medical condition that prevents providing a breath sample. If an exemption is granted, the interlock is removed but a much longer straight disqualification applies instead.
For a first high-range PCA, an exemption means an automatic 3-year disqualification with a minimum of 12 months, rather than the shorter interlock disqualification. So an exemption is usually not to the driver's advantage, and is for genuine practical or medical reasons.
What does the interlock involve in practice?
The driver arranges for an approved interlock device to be installed at their own cost, drives on the interlock licence for the set period, and must provide zero readings to start and, at intervals, while driving. Records are kept, and failing to comply can extend the period or affect the licence.
It is an added cost and inconvenience, but it keeps a person driving. Our notes on disqualification periods and why there is no work licence explain the wider picture.
Frequently asked.
What is the mandatory alcohol interlock program?
A program requiring certain drink-driving offenders, after a shorter disqualification, to drive only a vehicle fitted with a device that requires a zero alcohol reading to start it, for a set period on an interlock licence.
Who has to do the interlock program?
Drivers convicted of a defined list of alcohol PCA offences, including high-range PCA, some mid-range, repeat offences, refusing a breath analysis, and driving under the influence. An interlock order is the default for these offences.
Does the interlock get me back on the road sooner?
Yes. Under an interlock order the full disqualification is shorter, followed by a period driving on an interlock licence, so the time completely off the road is shorter than a straight disqualification.
Can I get out of the interlock program?
Only with an interlock exemption, granted in limited cases such as no access to a vehicle or a medical condition. An exemption means a much longer straight disqualification instead, so it is usually not an advantage.
What does the interlock cost?
The driver arranges and pays for installation of an approved device and drives on the interlock licence for the set period, providing zero readings to start and while driving. It is an added cost but keeps the person driving.
To speak to a criminal defence lawyer, call Aaron Kernaghan on 0421 717 019.
This article is written by Aaron Kernaghan, criminal defence lawyer at Good Legal Lawyers, as at 3 September 2026. It is commentary and reflects the personal opinion of the author only. It is not legal advice, it is not a substitute for advice on your own matter, and it does not purport to be accurate or complete. Any matter referred to may be before the court and any person charged is presumed innocent. For advice on a specific matter, contact Aaron Kernaghan on 0421 717 019 or contact the firm.
More criminal-law commentary by Aaron Kernaghan.
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