As New Zealand gets set to
rollout roadside drug testing, an Australian expert says
it’s a scattergun approach that doesn’t reliably pick up
impairment.
Wellington will next month become the
first location to see police use a saliva test on drivers,
with the rest of the country set to follow by
mid-2026.
The tests will screen four key drugs: THC,
which is found in cannabis, methamphetamine, MDMA or ecstasy
and cocaine.
Dr Michael White, an adjunct senior
fellow at the School of Psychology at the University of
Adelaide who’s researched road accidents involving cannabis,
says the tests are nearly worthless when it comes to picking
up if someone is impaired.
One of the main issues he
pointed out was that the tests detected the drugs but did
not reliably assess impairment.
He said the problem
was not just with the length of the detection window but how
many people are actually impaired after taking drugs like
cannabis.
“There’s a lot of research that says regular
cannabis users are not impaired even if immediately after
taking it so that produces a sort of questions of
justice.
It is a scattergun approach, many people who
are regular users won’t be impaired even if they test
positive”
The government said 30 percent of all road
deaths now involve an impairing drug – and that greater
screening will improve road safety.
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“We know that
they’re [drugs] a major factor in many road deaths and
serious injuries,” Transport Minister Chris Bishop said
earlier this year.
“We’re now making sure that police
are equipped with roadside oral fluid screening as a road
safety tool to enable the enforcement,” he
said.
Director of road policing Superintendent Steve
Greally announced earlier this month that Australian-based
company Pathtech Pty Ltd would supply the Securetec DrugWipe
3S devices, as well as oral fluid collection kits to collect
samples to be sent for laboratory analysis.
“Many
countries, including New Zealand, have seen a rise in the
number of drivers testing positive for drugs in recent
years, and the direct correlation to the number of people
being seriously injured or killed on our roads,” he
said.
The DrugWipe detects the presence of drugs in
saliva at or above a threshold that detects current or
recent use.
Dr White pointed out there had been no
robust evidence as to whether roadside testing has reduced
drug impaired driving or accidents.
“Australia has
been quite negligent on actually trying to evaluate roadside
drug testing.
“They’ve got a very passive approach,
they simply say RBT (random breath testing) for alcohol has
been successful, RDT (roadside drug testing) for drugs looks
a bit like random breath testing and therefore it ought to
be successful. There’s never been any evaluation in
Australia that clearly shows that roadside drug testing
actually works.”
He said there were differences
between how drugs and alcohol impairs drivers and testing
should be based on the crash risk.
“I think policy
should be based on crash risk, the crash risk from cannabis
is relatively low its less than for a BAC of 0.5. So
cannabis might increase your risk of crashing by up to 50
percent, alcohol at a BAC of 0.5 doubles your risk so it
increases it by100 percent”
For methamphetamine, Dr
White said it was more difficult as it might not actually
impair a person but instead make someone more aggressive and
increase their thrill seeking
The other key issue he
had with the testing was with legal drugs such as
benzodiazepines and opioids which he said can also result in
fatal car accidents.
“Some Australian research has
said that benzodiazepines account for twice as many road
crash fatalities as Cannabis and opioids account for twice
as many, now both of those are legal drugs.
So that’s
one thing that neither Australia nor New Zealand really
takes into account is the damage done by legal
drugs.”
Pharmacist and senior lecturer in Biosciences
at AUT Dr Catherine Crofts had also previously said she was
worried about the lack of information on what the new
testing could mean for people with prescriptions like
dexamphetamine.
Dr Crofts said about 50 percent of
people with ADHD in New Zealand are taking dexamphetamine or
lisdexamfetamine, which is becoming increasingly
popular.
“We know that some of the tests that are out
there in the community do cause some cross reactivity, and
I’ve just found that there are some that don’t,” she
said.
“But we haven’t seen anything about what the
police are going to do or how it is going to be managed when
somebody who is cross reacts, who is legally on these
medicines.”
Dr White said for subtle levels of
impairment some have suggested using phone applications to
assess people’s reaction times.
“I’m not convinced
that those apps are particularly good but at least they’re
trying to measure impairment which is a step in the right
direction rather than measuring presence”
He also
noted Australia and New Zealand did not efficiently take
human rights into consideration when it came to people
getting taken off the roads without showing any good
cause.
“In most other countries the drug testing is
associated with some sort of test of impairment, the police
have to have some sort of good cause to take you off the
road.
The Attorney-General’s report
into the legislation, written in July 2024, found it was
inconsistent with parts of the Bill of Rights Act,
specifically the right to be secure against unreasonable
search and seizure, and the right not to be arbitrarily
detained.
Minister of Defence Judith Collins had found
the intrusion on privacy was not proportionate to the public
interest objective.
“The intrusion on an individual’s
privacy that arises from the taking of a bodily sample for
the first oral fluid screening test appears disproportionate
where there is no basis to suspect the individual driving is
under the influence of an impairing drug,” she
wrote.
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