Mobile drug testing: high behind the wheel

Is mobile drug testing fair, or even effective?

The words "Mobile Drug Testing" over a green background with illustrations of marijuana leaves and smoke overlaying the text

Have you ever wondered whether you were “OK to drive” after a big night out, or a casual smoke with friends? Do you know how Mobile Drug Testing (MDT) works and what the consequences for being caught under the influence are?

With new legislation arising from reforms outlined in the NSW government’s Road Safety Plan 2021, drivers will face tougher penalties for driving under the influence of an illicit drug. Since MDT began in 2016, the number of tests conducted by police per year has been increasing, with an expected 200,000 tests to be conducted in NSW each year by 2020 — over 500 a day. If a driver tests positive in the roadside saliva test for cannabis, MDMA, methamphetamine or cocaine, they will be required to give another sample of blood or urine to have this result confirmed by a more accurate laboratory analysis.

Under the new laws, which came into effect last week, drivers who are found to have illicit drugs in their system could be fined immediately and have their license automatically suspended. Prior to these laws being introduced drivers would have the option to have their penalty determined in court. However, now electing to have one’s case appealed in court involves risking even harsher penalties. These new policies make up part of the NSW Government’s new plans to reduce road fatalities by 30 per cent from 2008-2010 levels by 2021.

What has not changed, however, is that penalties are issued based on the mere presence of substances in an individual’s system, rather than their presence above a certain threshold (as is the case with alcohol). The NSW Transport, Roads and Maritime Services website states that first time offenders found to have illicit substances their oral fluid, blood or urine may face fines of up to $2,200 and license suspension for up to six months, while repeat offenders may be fined up to $3,300 and have their license suspended indefinitely. By contrast, laws in the United Kingdom and Canada stipulate that drivers may only be charged if substances in their systems are found to exceed a certain threshold under laboratory analysis. Furthermore, Australian MDT methods and policy only specify illicit drugs, whereas British policy also covers the use of prescription medications such as benzodiazepines that are known to impair driving ability.

The disparity between these policies raises many questions regarding sensitivity and accuracy of the MDT devices: after what length in time can substances still be detected within the body, and does the mere presence of an illicit substance in the body automatically lead to driving impairment? Do these policies reflect a genuine concern for road safety, or do they represent another battle in the so-called ‘war on drugs’? Additionally, how will the growing use of medicinal cannabis fit in?

The Lambert Initiative at The University of Sydney is a centre of research that focuses on the discovery and development of safe and effective cannabis therapy. It was developed after the largest donation in history towards research at the University from Barry and Joy Lambert. The centre explores both the therapeutic benefits of cannabis as well as its safety implications in areas like driving.

Rhys Cohen, a senior project officer within The Lambert Initiative, spoke to Honi about the accuracy of MDT methods.

“We know that they are inaccurate and insensitive at testing for the presence of THC,” Cohen explained. When questioned further about whether the tests could accurately determine driving impairment he stated “they were never really set up to answer that question in the first place.”

“The intention of driving laws should be to protect people from unsafe drivers, but the law as it stands doesn’t specify how safe or unsafe a person may be.”

Iain McGregor, a research leader within the The Lambert Initiative involved in the research into cannabis and driving, also expressed scepticism about the accuracy of MDT in an interview with the ABC.” We found on occasion the tests gave a false positive when people have very low levels of THC and that is a concern for the carriage of justice, people are not impaired and they have not had cannabis for quite a long time.”

These claims are very concerning, especially considering that since the inception of MDT, there have been various claims made by drivers that passive cannabis smoking, or smoking weeks prior to a test lead to a positive MDT result. Prosecution in these cases would obviously be unjust, as driving ability would not have been affected.

In a recent monumental court ruling, driver Nicole Spackman, who had been charged with driving under the influence of cannabis, had her case overruled in court. Ms Spackman claimed she had not been smoking cannabis in the weeks prior to the test but had been in the company of a terminally ill neighbour who was smoking cannabis for medicinal purposes.

While police argued that passive smoking could not give a positive result, the magistrate ruled that there was insufficient evidence to disprove Ms Spackman’s claim. This ruling raises many concerns and questions regarding the fairness of current MDT methods.

The question remains as to whether Australia should set a threshold limit of detected cannabis within their driving laws, and whether current MDT is accurate enough to ensure fair prosecution. Further scientific research and policy development in this area will be critical with the growing use of recreational and medicinal cannabis use in Australia and around the world. Fortunately, the world-class research being conducted at The University of Sydney is helping to contribute to this ongoing debate.

So, how long should you wait after getting high before driving? Basically, we still don’t know — sorry.