Interlock Devices in Queensland — How They Work and Who Needs One
Drink Driving — 2026-08-21 — by Sacha Sarah Smith, Civic Law
The interlock is not ordered by the court — it comes from Transport and Main Roads after your disqualification ends. Which convictions trigger it, why a work licence does not avoid it, how the twelve months can stretch, what it costs, and the narrow grounds for an exemption.
The interlock is not part of the sentence. A magistrate deals with the fine, the disqualification and whether a conviction is recorded, and then the file closes. The alcohol ignition interlock comes afterwards, from the Department of Transport and Main Roads, and it governs what can be driven once the disqualification runs out.
An interlock is a breath testing device wired into the ignition of a car. The engine will not start unless the device gets a breath sample with no alcohol in it, and it can ask for another sample part way through a trip. It has a camera that photographs whoever blows into it, and it sends that data to Transport and Main Roads.
The rules sit in part 3B of the Transport Operations (Road Use Management) Act 1995 (Qld). Our drink driving penalty estimator gives an indication of whether a reading falls inside the program, and Sacha will say at the first consultation how it applies to the charge you are facing.
The Convictions That Put You in the Program
These are the convictions defined as "drink driving offences" under section 91I. If you are convicted of one and disqualified because of it, the interlock condition attaches to the next Queensland licence you are granted.
Driving under the influence. A conviction under section 79(1) — which includes any reading of 0.150 or above, because that reading is treated as driving under the influence. A work licence is not available for this charge, and the interlock applies on top of the disqualification.
A reading of 0.100 or above. The middle alcohol limit offence under section 79(1F). This is where most people meet the program for the first time, and it applies whether or not it is your first offence.
Refusing the breath or blood test. A conviction under section 80(11) for failing to provide a specimen for analysis at the station. Refusing does not keep you out of the program — it puts you in it.
Dangerous driving affected by alcohol. Dangerous operation of a vehicle under section 328A(1) or (4) of the Criminal Code, where the charge carries the circumstance that you were adversely affected by alcohol.
Two drink driving offences in five years. A low or general alcohol limit offence — including a first offence reading under 0.100 — counts if you were convicted of another drink driving offence in the five years before it. One low reading on its own does not put you in the program. Two do. Our article on repeat drink driving sets out what else changes on a second offence.
Driving in breach of the program itself. Convictions under sections 91W and 91X — driving a car you are not allowed to drive, or ignoring the conditions of an exemption — are themselves drink driving offences for this purpose.
A Work Licence Does Not Get You Out of It
This is the point clients are most often surprised by. A restricted licence granted by the court carries the interlock condition under section 91K(2), so a work licence does not sit outside the program.
The device goes on the car you drive for work. Including a work vehicle. If the vehicle belongs to your employer, your employer has to agree to the interlock being fitted, and that is a conversation worth having before your application is filed rather than after.
Your interlock time starts on the day the order is made. Under section 91M(1) the clock runs from the date the court grants the restricted licence, not from the end of the disqualification — so a work licence can mean you finish the program sooner.
You can nominate more than one vehicle. Section 91L lets you nominate any vehicle of a class your licence covers — your own car, a partner's car, your employer's vehicle — as long as each has a device fitted.
Anyone else who drives that car has to blow into it too. The device does not know whose car it is. Family members driving the nominated vehicle provide a sample and have their photo taken like everyone else.
Whether a work licence is available to you at all depends on the charge and your licence type. Our work licence eligibility tool gives an immediate answer, and the full rules are in our work licence guide .
Twelve Months Is the Minimum, Not the Length
The program runs for a minimum of twelve months, and that twelve months only counts while you hold a valid licence with a device fitted to a nominated vehicle. That twelve months is called the prescribed period under section 91N, and it does not have to be continuous — if your licence lapses or you take the device off, the clock stops until it goes back on.
Eight months learning, four months performance. Transport and Main Roads runs the twelve months as an eight month learning period followed by a four month performance period, and it is the last four months that are watched most closely.
A positive sample in the last four months restarts those four months. Under section 91VA, if the device records alcohol or you get a permanent lockout for missing a service during the final four months, your end date automatically moves to four months after that event. Every time.
Missed services cost you the same way. The device has to be serviced one month after installation, then every three months. A missed service appointment triggers a lockout, and the lockout counts as one of those events.
Tampering or letting someone else blow for you adds four months. Transport and Main Roads can extend the period under section 91U where you drove without providing a sample, drove knowing the device was faulty, or drove knowing it had been interfered with. You get a show cause notice first and at least 28 days to respond, under section 91V.
Five years is the outer limit. The interlock period ends five years after your disqualification finished under section 91M, whether or not you ever fitted a device. That is the practical meaning of not participating — you do not drive for five years, and then the condition falls away.
What It Costs and What Help There Is
The cost is yours, not the court's, and it is paid to the interlock provider rather than to Transport and Main Roads. Budgeting for it matters, because the program cannot start until the device is fitted.
About $2,600 for twelve months. Transport and Main Roads estimates that figure for installation, leasing, servicing, data uploads and removal at the end. Extra fees can apply if you breach the program rules [qld.gov.au, 2026-08-21].
A 35 per cent discount on a concession card. A valid Australian Government Health Care Card or Pensioner Concession Card gets you that reduction from your provider. It does not reduce the licence fees.
Financial assistance if you are under the income limits. Transport and Main Roads pays the provider directly for fitting, rental, servicing and removal if your income and savings fall under published thresholds — for a single person in the workforce with no children, an annual income under $38,446.28 and under $3,000 in the bank as at 31 December 2025. You can only get it once every five years, and you apply on form F4899.
Licence fees on top. You pay an interlock condition fee plus the ordinary licence fee when you apply for the licence with the "I" code on it.
You cannot drive the car to the fitting appointment. The licence comes first, the device second, and someone else has to drive the vehicle to the installer.
Exemptions Are Narrower Than People Hope
An exemption releases you from having to fit a device, and the grounds set out in section 91Q(3) are limited. Not being able to afford it, or needing to drive for work, is not one of them. Sacha will tell you at the outset whether an exemption is realistic for you, because relying on one that never comes is how people end up driving when they should not be.
Distance from an installer. Where your home is further from the nearest interlock installer than the distance or travel time set by regulation, or outside the radius they service, including any mobile fitting service. Transport and Main Roads describes this as living in a remote location or on an island.
A medical condition. Where a doctor certifies you cannot provide a breath sample strong enough to operate the device. That certificate goes in with the application on form F4864.
Severe hardship. Transport and Main Roads accepts applications on the basis of severe hardship to you or a family member — but not hardship that comes down to employment, education or money.
Timing. You can apply up to six weeks before your disqualification ends, or straight away if the court has granted you a restricted licence, and there is an application fee. Transport and Main Roads has 28 days to decide, and if it does not decide in that time the application is taken to be refused, which you can have reviewed.
Carry the certificate. If you are granted an exemption you have to produce the certificate when a police officer asks whether you are allowed to drive the car. Not having it on you is an offence in itself under section 91W(4).
Driving Outside the Condition Is a Fresh Charge
Once the interlock condition is on your licence, driving a car without a device fitted is not a licensing problem. It is a criminal charge with a mandatory disqualification attached.
A car with no device. Up to 28 penalty units — fines in Queensland are counted in penalty units worth $172.70 each, so $4,835.60 — for a first offence under section 91W(1), or 60 penalty units, $10,362, if you have been convicted of the same thing within the previous five years. The court must also disqualify you for three months, or six months on the repeat.
A car with a device that is not yours. Driving a vehicle fitted with an interlock that you have not nominated carries up to 28 penalty units.
Breaching the terms of an exemption. The same amounts apply under section 91X, with the same mandatory three or six month disqualification.
Skipping the program and driving anyway. If you never take out the interlock licence and are caught driving, that unlicensed driving conviction carries a further disqualification of one to six months under section 78(3)(j) — and it is itself a drink driving offence, so the program starts again on the other side of it.
There is one thing the interlock does not do. It does not shorten your disqualification, and it does not start until that disqualification is served. Anyone who tells you a device gets you back on the road early is wrong.
Talk to Civic Law
Whether the program applies to you is fixed by the charge you are convicted of — but the charge itself is not always fixed. The difference between a reading of 0.098 and 0.101, or between a plea to one charge rather than another, is the difference between twelve months of blowing into a device and none.
Sacha assesses at the first consultation whether the interlock program will apply, what it will cost you across the year, and whether a work licence is available to shorten the time you spend in it. Call Sacha Sarah Smith on 0425 429 458 before your court date — the preparation that reduces a disqualification is done before you get to the courtroom, not on the day.
Drink Driving — Guilty Plea
Work Licence Application