A positive roadside drug test in Queensland means two things straight away. Your licence is suspended for 24 hours, and your saliva sample goes to a laboratory. It does not by itself mean you were impaired, and it does not tell you which of two very different charges you are facing. That second question is the one that matters most, and it is usually not answered at the roadside.

Here is what actually happens, in order.

What the saliva test looks for

Four drugs. The Queensland Government and the Queensland Police Service both identify them as methylamphetamine, which covers speed and ice, MDMA, which is the active ingredient in ecstasy, THC, which is the active ingredient in cannabis, and cocaine.

That is the list. The roadside test is not a general drug screen and it is not looking for prescription medication generally.

The important word is presence. This is a zero tolerance test. It is not measuring how much is in your system or whether it was affecting your driving. It is looking for whether the substance is there at all.

What happens at the roadside, step by step

The Queensland Government describes the process. You are asked to provide a saliva sample, and the test takes three to five minutes to return a result.

If it is negative, you go.

If it is positive, you are asked to provide a second saliva sample for a second test. If that one is also positive, the samples go to a laboratory for analysis.

The next 24 hours

The Queensland Police Service states that if you test positive for a relevant drug, your driver licence is suspended for 24 hours.

That is immediate and it applies whether or not you are eventually charged, and whether or not the laboratory later confirms anything. Do not drive away from the roadside. People do, having convinced themselves the test was wrong, and they turn one problem into two.

What happens to your licence after that first day depends on what you are charged with and on whether you already have another charge on foot. The Queensland Government indicates that being charged with driving with a relevant drug present does not by itself suspend your licence, but that where you have pending charges your licence is suspended immediately.

The two charges, and why the difference decides everything

This is the part worth reading twice.

Driving with a relevant drug present is the saliva offence. The question is whether one of those four drugs was in your system. Impairment is not part of it.

Driving under the influence of a drug is the more serious one. The Queensland Government describes it as involving a blood specimen and as being about your ability to drive being affected. The Queensland Police Service notes that where an officer suspects your ability to drive has been impaired by any drug, you can be required to provide a blood sample.

Those are different offences with different consequences, and one practical difference is very large. A work licence can be available where the charge is driving with a relevant drug present. It is not available where the charge is driving under the influence of a drug. So if you drive for a living, the first thing to establish is which charge is actually on your paperwork rather than which one you assume it is. Our page on drug driving sets out how the two run, and our page on work licence and hardship applications covers what that application involves.

What the roadside test does not prove

It does not prove you were high. It does not prove you took anything that day. THC in particular can be detected after the effect has worn off, which is why people who used days earlier are genuinely surprised to test positive.

That surprise is understandable and it is also not a defence. The presence offence is drafted around presence. Feeling completely sober at the time you were tested does not answer the charge you have been given.

If you have a prescription, including medicinal cannabis

Queensland's position on this is settled and it is strict.

A Queensland Government statement announcing changes to road safety laws confirms that the state will continue its zero tolerance approach to drug driving, including for medical cannabis prescriptions, after a review found no evidence to support a change.

So a lawful prescription does not put you outside the presence offence for THC. If you are prescribed medicinal cannabis and you drive, that is a specific situation to get advice about rather than something to assume your way through.

Penalties are changing on 1 December 2026

The same Queensland Government statement announces that from 1 December 2026 penalties for drug driving are being doubled, with higher fines and longer licence disqualifications, along with strengthened penalties where drink and drug offences are combined and the introduction of minimum court imposed fines.

Which means any penalty figure you find in an article written before that date is worth treating with suspicion, and the date your offence was committed matters. This article is current as at August 2026 and the penalty position specifically should be checked against current Queensland Government material.

What people mean when they search for loopholes

Usually they mean whether there is anything technical that can be raised.

The honest answer is that drug driving matters are process driven, and the process is where any real question lies. Whether the requirement to provide a sample was properly made. Whether the procedures were followed. Whether the certificate that comes back from the laboratory says what it has to say, about the right sample, analysed the right way. Those questions either exist on the material in your matter or they do not, and nobody can tell you which before reading it.

What is not a loophole is feeling fine, having a prescription, or having used days earlier. Those are the three most common hopes and none of them answers a presence charge.

What to do this week

Find out the exact wording of your charge. Presence or under the influence. Everything else follows from that.

Do not drive during the 24 hour suspension, and check what your licence status is after it.

Write down the sequence while it is fresh. When you were stopped, what you were asked, what you provided, what you were told.

And if you drive for work, raise that early rather than at the courtroom door, because the application that might keep you on the road has to be prepared before the day.

If you have been tested in Cairns and you are waiting on a lab result

The wait between a roadside test and a decision about charges is unsettling, and it is also the useful time. What can be done about your licence is largely decided by preparation that happens before your first court date.

We act in drug driving and traffic matters in Cairns and across Far North Queensland. If you have returned a positive roadside test and you are not sure what happens next, we can go through it with you.

If you have returned a positive roadside drug test in Cairns, speak with us before your first court date.