The Government has confirmed they will “roll out” legislation this year to enable police to randomly test the saliva of drivers using inaccurate swabs that could see thousands of people subjected to roadside blood tests and prosecuted with no evidence of impairment. Here’s why the policy won’t make our roads safer, and why you should be concerned.

This was first published on The Daily Blog and discussed on 95bFM’s Marijuana Media with Chris Fowlie from NORML and Milly from bFM Drive – thanks to The Hempstore!

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Let us start by saying no one should be driving while impaired. We all want safe roads and safe drivers. NORML has long said the responsible cannabis consumer does not operate a motor vehicle or other dangerous machinery impaired by cannabis, nor (like other responsible citizens) impaired by any other substance or condition, including some medicines and fatigue.

Instead of randomly testing 50,000 drivers using inaccurate saliva swabs which deliver false positives and are not actually calibrated to detect impaired drivers, a tech-based approach would be more effective, and cannabis legalisation could make our roads safer while balancing the budget and saving thousands of public-sector jobs.

Residual levels of cannabinoids are not correlated to, or predictive of, impairment

The oral devices don’t show impairment, and neither does a blood test.

The law sets an arbitrary per se limit of, for cannabis, in either fluid of 1ng for a fine and 3ng for criminal prosecution – but a recent study found the detection of THC or its metabolites in bodily fluids is not correlated with impairment.

The literature review by UC Davis researchers, published in the Journal of AOAC (the Association of Official Analytical Chemists) International, said this includes blood, breath, urine, or saliva.

Researchers concluded that there is “no direct relationship between impairment and THC concentrations” in subjects’ bodily fluids.

“Current methods that focus on THC and/or metabolite concentrations in blood, saliva, urine, or exhaled breath can lead to false-positive results for recent use due to the persistence of THC well outside of the typical 3-4-hour window of potential impairment following cannabis inhalation.”

That conclusion is consistent with numerous studies reporting that neither the detection of THC nor its metabolites in blood, saliva or other bodily fluids is predictive of impaired driving performance.

Saliva testing of drivers is already allowed

Despite the evidence, the law already allows saliva testing of drivers. The Land Transport (Drug Driving) Amendment Act 2022 was passed by Labour with the support of every other party including National, and with only the Greens opposing it.

The main justification, still routinely cited by now-Transport Minister Simeon Brown, is that drivers in New Zealand impaired by drugs now cause as many deaths as drunk drivers.

The analysis by ESR is junk science. They counted drivers with any trace of illicit drugs (not just those who were impaired), but ESR only included drunk drivers who were over the legal limit (ignoring potentially many more who were impaired but below the limit). Curiously, the US says 25% of road deaths involve alcohol or drugs, half of ESR’s claimed rate here.

Nevertheless, the law took effect last year and creates an offence for driving with a qualifying substance in blood or saliva.

They’re not trying to detect impairment

The offence is not actually being impaired on the road. The offence is another version of drug possession (in bodily fluids). This could be yet another criminalisation of non-problematic drug use.

The expert committee charged with setting an impairment threshold for “qualifying substances” in bodily fluids could not find evidence that any number would show impairment so just went with two arbitrary figures which they claimed would instead show recent use:

  • 1ng/ml in either blood or saliva is deemed to be ‘low risk’ and would get a fine and demerit points;
  • 3ng/ml is apparently ‘high risk’ and would lead to criminal proceedings.

The two-tiered penalties are aligned with the approach to drunk driving. But there is no evidence to support how those figures were chosen.

The law was amended so references to impairment are now references to recent use. But the available evidence suggests that regular cannabis users – which would include most medicinal users – can have higher levels for days after cessation, long after any impairing effects have worn off.

Existing oral devices are all unreliable

Much to the chagrin of police and the National Party, the existing law requires oral devices be accurate to an evidential standard. But the available devices are not reliable and can’t be used in proceedings.

Australia has used oral test devices for several years as a screening tool. An estimated 20 per cent of tested drivers are either falsely accused of being impaired, or are impaired but not detected.

This was known at the time our law was passed. So, our law bizarrely requires a driver fails two oral devices – because failing one cannot be trusted with any certainty.

Our police haven’t been using them, instead using Compulsory Impairment Tests (walk a straight line, etc) and blood tests if they have cause.

A small change with big, unexpected consequences

Following a request from Police and MoT officials, a briefing paper had gone to Kiri Allen & Ginny Anderson last May and was approved by Labour’s cabinet. Their cabinet paper says it would require a law change, which has now been picked up by National.

Transport Minister Simeon Brown says he will amend the existing law by the end of this year. This will enable the oral swabs to be used to randomly test any driver, with a subsequent blood test used as evidence. He expects police to randomly test the saliva of 50,000 drivers every year.

This small legislative change will have big consequences. But the result won’t be the promised gains in road safety, but the unintended prosecutions of potentially thousands of innocent drivers.

The change will let police randomly use oral swab devices (known to be inaccurate) to trigger a compulsory roadside blood test (by force if necessary) which will have no relation to, or predictive power of, any level of impairment by the driver.

This will align our law with Australia, where people are routinely prosecuted for inactive metabolites or low residual levels that are not indicative of impairment.

Like in Australia, our Police will waste a huge amount of time and effort erroneously testing and prosecuting drivers who aren’t impaired, while missing a significant chunk of those who are impaired, therefore failing to achieve the stated objectives of the policy.

Another Australian phenomenon we can expect to see: the middle classes and wealthy using Ubers to get everywhere, while those who can’t afford to do that will be subject to intrusive roadside testing.

Your own phone could do a better job

Police could use a test that actually detects impairment – such as a tech-based approach like the DRUID app or the Alertometer app now used by livestock truckers with the blessing of Waka Kotahi.

These can be installed on a typical smartphone and used before a shift or safety-related task such as driving. The app measures responses to visual and other prompts in a game-like way and compares this to a user’s baseline data gathered using the sensors embedded in the phones we all carry.

This is the 21st Century approach but oral swabs seem so… 1950s.

The medical defence

The good news is that New Zealand drivers, unlike Australia, have a medical defence.

A driver prescribed medicinal cannabis – or any other prescription medicine including pain meds and sleeping pills and whatever else you’re on – has a defence to proceedings as long as they’re following their doctor’s instructions.

Typically, that may be “Don’t drive for 4 hours after use.” This is very good advice. It is more accurate than saliva tests, and another reason to get a prescription.

Read the full story at The Daily Blog:

Testing times for drivers: National’s new drug-driving law won’t detect impaired drivers & could see innocents prosecuted | The Daily Blog

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