Australia has made major progress in curbing drink driving. Decades of random breath testing, enforcement and powerful social media campaigns have cut alcohol-related road deaths significantly.
Author
- Milad Haghani
Associate Professor and Principal Fellow in Urban Risk and Resilience, The University of Melbourne
Yet new data show more fatal crashes now involve drugs than alcohol.
So, how has drug driving become so prevalent despite strict laws? Why has deterrence succeeded for alcohol but faltered for drugs? And what policy and behavioural changes can reverse this growing source of road trauma?
National trends
National crash data confirm the changing face of road risk.
Between 2010 and 2023, fatal crashes involving drug driving rose from 7.6% to 16.8% - an increase that makes drug driving the most common risk factor in fatal crashes.
During the same period, crashes linked to drink driving fell from 21.6% to 12%, while those linked to not wearing seat belts dropped from 15.3% to 14.7%.
A breakdown of drivers and motorcyclists shows how drastically the balance has shifted.
Among drivers, the share of fatalities involving an illegal blood alcohol concentration has fallen steadily - from about 30% to 14% between 2008 and 2023.
Among motorcyclists it dropped even further, from 27% to 10%.
Yet over the same period, deaths where drugs were detected surged in both groups - roughly quadrupling for drivers and motorcyclists alike, now accounting for about one in five motorcyclist fatalities.
State-level data
Last year in Queensland, there were 49 road fatalities involving drugs , compared with 42 involving alcohol.
In July 2023, the state expanded roadside screening to include cocaine , with more than 1,400 positive detections since.
In New South Wales, drug driving charges have risen more than 30-fold since 2008 . Testing volumes have increased, but so, too, has the percentage of positive results, from roughly 2% to peaks near 18%.
Toxicology records confirm a parallel rise in the proportion of road deaths where drugs are detected compared to alcohol, indicating the trend cannot be explained by the increase in testing volume alone.
In Victoria, about 3% of licensed drivers are tested for drugs each year, targeting cannabis, methamphetamine and MDMA.
South Australia has just announced its testing regime will be expanded to include screening for cocaine .
How does testing work?
Drivers are first screened for alcohol when they are stopped. If no alcohol is detected, police may ask for an oral-fluid test using a saliva swab .
The process detects trace amounts of illicit drugs, not impairment itself.
The swab collects saliva, producing an initial result within minutes. If a test shows a positive reading, a second sample is taken and sent to a laboratory for confirmation.
Unlike alcohol testing, which measures a driver's blood-alcohol concentration against a defined legal limit, drug testing operates under a zero-tolerance rule .
This means any measurable amount of the targeted drugs - cannabis, methamphetamine, MDMA or cocaine in most states - is an offence.
Roadside drug tests are more complex and costlier than breath tests.
In 2024, Australian police conducted about 10.3 million random breath tests , resulting in roughly 58,000 positive detections - a positive rate of 0.6%.
By contrast, there were only 500,000 roadside drug tests but they yielded more than 52,000 positive results - a tenfold higher detection rate.
Behavioural factors
Recent studies show drug driving has grown mainly for three overlapping reasons:
- perception among drivers they won't get caught
- perception of weaker social stigma around drug driving
- drug testing remaining far less frequent than alcohol testing.
Many drivers believe they won't be caught. Exposure to roadside drug testing remains low - in some states, fewer than 2% of licensed motorists are tested in a year.
Meanwhile, some social media users send out "police-location" alerts which can help other drivers avoid enforcement sites.
These factors lower the perceived risk of apprehension.
Recent Australian research also found a stark contrast in how drivers view alcohol and drug impairment.
Participants often described drink driving as more dangerous and socially unacceptable whereas drug driving was often considered less risky and less likely to attract police attention.
Misconceptions and lack of awareness about the impairment effects of drugs may also contribute: drug users often perceive their driving ability as unimpaired .
In reality, the drugs most often detected have very different impairment profiles - but all, in their own ways, increase the risk of a crash .
Stimulants such as methamphetamine or cocaine can make drivers more aggressive and reckless. Cannabis slows reaction time, impairs people's judgement of time and distance, and reduces coordination, particularly within the first few hours after use.
Using drugs together, or combining them with alcohol, further amplifies impairment.
What can be done?
Australia's success in curbing drink driving came from the right mix of laws, visibility and social messaging.
Tackling drug driving will require the same balance but adapted to new realities.
Four strategies could make a difference:
Testing strategically. Sheer volume isn't enough. Enforcement should focus on unpredictable, data-driven deployments - targeting high-risk times, routes and driver groups. Deterrence improves when testing resources are used strategically .
Creating more visibility. Drivers don't need to be tested to be deterred. Regularly seeing roadside operations can raise the perceived risk of being caught.
Countering evasion networks. Social media platforms and group chats that warn users about testing locations undermine deterrence . Police can counter this by tracking these alerts and rotating testing sites and times.
Reframing the message. Public campaigns must highlight how long impairment lasts, the risks of mixing substances and the illusion of control many drug-using drivers report. Australia's iconic anti-drink driving slogans - such as " if you drink, then drive, you're a bloody idiot " - helped build powerful social norms. A new generation of drug driving campaigns will need to do the same.
Milad Haghani receives funding from The Australian Office of Road Safety.
