On 6 June, the ACT Legislative Assembly Standing Committee on Health tabled its report on Labor backbencher Michael Pettersson’s private member’s bill to legalise the personal possession and use of cannabis in the capital territory.
And the committee outlined that it overwhelmingly supports the legislation, subject to a number of recommendations, the ninth of which being that the “ACT government collaborates with ACT Policing to adopt a cannabis drug driving test that determines impairment”.
The ACT has a similar method of roadside drug testing to the highly derided NSW regime. In this state, NSW police test drivers for the mere presence of a select four drugs, one of which is tetrahydrocannabinol (THC): the psychoactive component of the cannabis plant.
Roadside testing does little for traffic safety, as officers have no way of gauging whether a driver is actually intoxicated. But, it does act as a backdoor method of penalising people for drug use. And as THC remains in the body for a long time, penalties can relate to consumption weeks prior.
But, over in the States, where cannabis use is increasingly the norm, authorities aren’t concerned with penalising people over what’s an accessible legal medicine in 33 states, while in 10 states and the District of Columbia, it’s a lawful recreational drug that a quarter of the population can use.
Instead, the US government and policing agencies are now focusing on how THC affects an individual’s driving capacity, and whether these effects make drivers more prone to causing traffic accidents.
Two very different drugs
“That marijuana usage increases a driver’s risk of crashing is not clearly established,” wrote David Randall Peterman, a US analyst in transportation policy. Some studies, he found, estimate “a small increase” in the risk of crashing, while others “estimate little or no increase in the likelihood”.
Mr Peterman detailed his findings in the Congressional Research Service report Marijuana Use and Highway Safety, which was tabled in US Congress on 14 May this year. The Congress-commissioned report provides a summary of relevant research into driving after cannabis use.
The analyst points out that as the legal use of cannabis grows, so too do concerns over its impact on road safety in a similar way to alcohol. Although, he determines that the differences in the effects of the two drugs, may challenge the assumption of simply treating cannabis and drink driving the same.
While alcohol is a depressant absorbed into the blood and metabolised quickly, with almost no traces within 24 hours, THC is a stimulant that’s metabolised rapidly as well, however it’s stored in the fat cells, so traces can still be present several weeks after consumption.
Difficult to pin down
As of last month, 18 US states have enacted laws that test for specified levels of THC in a driver’s body. If these are exceeded it constitutes driver impairment and is therefore unlawful. This is similar in the way that driving with 0.08 blood alcohol content or over is illegal in the States.
However, despite these laws, Peterman finds that determining THC impairment levels is not as straightforward as it is with alcohol. While the psychoactive part of THC drops dramatically after an hour of use, due to the way it’s metabolised the non-psychoactive traces remain for weeks.
Other reasons why the effects of THC on driving performance are relatively unknown is the until recently complete illegality of the drug, the fluctuating THC potency between plants, as well as the different effects it can produce through various methods of ingestion.
And the results from studies on the association between cannabis use and crash risk are also “inconsistent”. Peterman cites one study that found the increased risk of crashing after its use was 1.83 times that of an unimpaired driver, while another study found no association at all.
Safer than alcohol
A 2017 National Highway Traffic Safety Administration driving simulator study found that cannabis-dosed drivers took fewer risks than when they weren’t under the influence of the drug. And it was surmised that drivers conscious of their state drove more carefully to compensate.
The NHTSA researchers also found that drivers who had been drinking “tended to drive faster than the speed limit”, drove closer to the car in front of them, and in general, took more risks than when they weren’t under the effects of alcohol.
Although, a 2017 National Academy of Science report and a 2018 National Institutes of Health study both found that cannabis use increased the risk of motor vehicle accidents. The NAS report found there was substantial statistical evidence to support the heightened risk.
A standard still eludes
Peterman recommended that the US Congress continues to invest in research on “whether a qualitative standard can be established that correlates the level of THC in a person’s body and the level of impairment”, as well as collecting better data in regard to cannabis and driver use of it.
“The concentration of THC in a person’s blood rises rapidly after consumption, then drops rapidly, within an hour or two,” Peterman concluded towards the end of his report. “Impairing effects appear rapidly, but may remain for some time.”
And due to this, the analyst states that the amount of THC in a person’s body is a poor indicator of impairment, or, indeed, whether the individual has actually used it recently or whether they were “simply exposed to second-hand smoke”.
An unjust drug war tactic
Recently, Lismore Magistrate David Heilpern ruled that Nicole Spackman was not guilty of drug driving, because the THC in her system was due to passive smoking. And in 2016, he found Joseph Carrall innocent of the same charge because he last smoked a joint nine days prior to testing.
Throughout the state, there’s a growing awareness that the NSW roadside drug testing regime is a flawed system that’s unjustly punishing people for cannabis driving whilst they’re not actually under the influence of the drug.
And while the US report sets out that there’s no clear way to determine the effects of cannabis use on driver performance as yet, it’s very clear in the assertion that THC is a substance that stays present in the body for weeks after it no longer has an impairing effect upon an individual.
So, the only conclusion to draw is that regardless of its initial aim, today, roadside drug testing in NSW is being used to penalise a great many drivers for using medicine legally, or having traces of an inactive illegal substance in their body, which in some cases is through no fault of their own.