Roadside instant drug testing is under scrutiny after an SA driver falsely tested positive to having methamphetamine in his system, resulting in a loss of licence.
Kevin tested positive on an initial swab collected during a roadside drug test about two weeks ago, despite having no drugs in his system.
However, he was issued with a 24-hour immediate loss of licence by police, and later received correspondence telling him he had lost his licence for three months.
A saliva test collected by police at the same time, which was sent to a lab for testing, cleared him of having drugs in his system and the loss of licence was reversed.
So, what are roadside drug tests? And how accurate are they?
What tests are used around Australia?
When Victoria introduced roadside drug testing in December 2004, the step was hailed as a “world first” and other states soon followed suit.
According to South Australia’s road traffic regulations, and a recent freedom of information document posted on SA Police’s website, the “apparatus for a drug screening test” in the state was a saliva detection device called a DrugWipe II Twin.
“This equipment is manufactured by Securetec in Germany”, the website states.
Such devices are widely employed across Australia, with product supplier Pathtech’s website stating that the Securetec DrugWipe was “currently used by all Australian police jurisdictions”.
NSW Police’s standard operating procedures state that the DrugWipe is “to be used for initial oral fluid testing prior to considering secondary testing and sampling”, while Queensland Police Service’s website confirms the DrugWipe, “which can detect the presence of one or more … drugs with a simple tongue swab”, was also in use.
“The first test used (non evidentiary) is a Securetech DrugWipe 3S,” QPS told the ABC.
“The second (non evidentiary) is a Draeger Drugtest 5000 (using Draeger DCH/STK consumables).
“Following this, the sample is sent to Queensland Health Forensic Services Section for analysis.”
Swinburne University psychopharmacologist and research fellow Thomas Arkell said states differed in the details of their random drug testing regimes, it was common practice to do more than one spot test.
“There’s normally a two-stage process that would happen at the roadside,” he said.
“You wouldn’t be issued with an immediate licence disqualification unless that second test also came back positive, and if that was positive a third sample would be sent onto the lab.”
In Kevin’s case, he was given roadside test, and did another saliva swab which was sent to a lab.
Tasmania’s police, fire and emergency management department told the ABC that Tasmania Police used the Drug Wipe 5S OFT test, which detects cannabis, hashish, marijuana, amphetamines, methamphetamines, cocaine and opiates.
If a driver returns a positive test result, police officers can collect an oral fluid sample.
Are they accurate?
The case involving Kevin is not the first time the reliability of the tests has been called into question.
A 2019 study published in the journal Drug Testing and Analysis found that both the Securetec DrugWipe and the Draeger DrugTest 5000 sometimes delivered incorrect results.
Both companies have been contacted by the ABC for comment.
Dr Arkell told the ABC the quick tests were similar to rapid antigen tests used for detecting COVID-19 and were less reliable than lab tests because they often presented false positives or false negatives.
“The tests they use in the lab are extremely sensitive bits of analytical chemistry equipment which are able to detect down to very small amounts exactly how much of a drug is in your system,” Dr Arkell said.
“These tests that are used at the roadside are binary things, they come back ‘yes’ or ‘no’ depending on whether a certain amount of drug is detected at or above a certain limit.”
But drug epidemiologist Paul Dietze said the frequency of false positives (when drugs were incorrectly detected) was likely to be noticeably lower than that of false negatives (when drugs go undetected), meaning there were more drug drivers going unnoticed than there were non-drug drivers being falsely accused.
“The false positive rate is, to my understanding, quite low,” said Professor Dietze, from Curtin University’s National Drug Research Institute.
“But the false negative rate for some drugs can be quite high … and the performance of the test can be judged on that.”
Professor Dietze said that, while they were less common, false positives could be “very traumatic for the individual concerned” — a point echoed by Dr Arkell.
“There is a use for these tests. They’re useful screening devices in the field, but the idea that you can have your licence disqualified after a single test that could be a false positive is to me very concerning,” Dr Arkell said.
With quick roadside tests, substances in a person’s saliva reacts with the device which causes a positive result, Dr Arkell said.
“It’s similar to a COVID test or pregnancy test — if something is detected it causes a reaction and you get a positive test result,” he said.
“Using a single swab at the roadside without confirming that with a second test is fraught with issues.”
Dr Arkell pointed to New Zealand where police said they could not find a “suitable” oral fluid testing device to carry out random roadside drug tests.
What happens if you test positive?
The rules vary for each state and territory.
Drivers in New South Wales who test positive to an initial mobile drug test will be directed to provide a saliva sample, which if it returns positive, will result in a 24-hour loss of licence, according to the Centre of Road Safety.
In Victoria and Queensland, drivers who return a positive result to an initial test will be required to take a second test which, if positive, will be sent to a laboratory for further analysis.
The Western Australia’s Road Safety Commission said drivers found with cannabis, ecstasy or methamphetamine in their oral fluid sample can be charged with drug driving.
ACT Policing said drivers can only be charged with a drug driving offence if they test positive on a saliva test analysed in a laboratory.
However, in South Australia officers can issue an immediate loss of licence to a driver “if they commit a drug driving offence” by testing positive to a roadside drug test following laws introduced into that state in February last year, according to police.
Why can spot testing be important?
Professor Dietze said that, while the current roadside tests were not without issues, the broader principle of roadside testing was an important one in the battle to reduce fatal and serious injury crashes.
“There’s certainly a place for roadside testing within a road safety regime. The queries still remain about the effectiveness of the devices that are there and it’s important that we keep abreast of any developments of new devices,” he said.
“Methamphetamine detections in fatalities and serious injuries have been going up so, that’s a major concern and we need to work out effective countermeasures.
“If you take someone who’s impaired [by drugs] off the road, then potentially that has road safety benefits, no question.”
According to SA Police’s response in 2023 to a freedom of information request, more than one in five of the state’s road deaths between 2017 and 2021 were linked to drugs.
“During these five years, there were 486 lives lost, 100 of which were related to drug driving,” SAPOL said.
“This equates to 20.6 per cent of all lives lost.”
Professor Dietze said what he would like to see is a broader response to drug driving that retained random testing, but complemented it with other measures.
“The key thing is to make sure that this [roadside testing] is seen as just part of the mix in terms of trying to respond to drug driving,” he said.
“We [need to] work out strategies to manage people’s alcohol and other drug problems that will prevent them from actually thinking drug driving is an acceptable behaviour.”