• marijuana is legal in Canada

Where’s the Weedalyzer when we need it?

Now that marijuana is legal in Canada.

Jim Kenzie By: Jim Kenzie December 6, 2018
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Anybody who thinks marijuana is a performance-enhancing drug has never seen a stoner trying to operate a can opener.

Now that marijuana is legal in Canada, one question must still be asked: is marijuana a performance-inhibiting drug, especially when it comes to driving?

I visited the headquarters of ACS (Alcohol Countermeasure Systems) in Toronto recently to learn more about DWH — Driving While High (my neologism) — which is bound to become ever more critical in the coming years.

As its corporate name implies, ACS got its start developing and manufacturing world-class alcohol-detection devices.

And yes, they actually manufacture many of these ultra-high-tech products right here in Toronto.

I thought the ACS name sounded familiar — turns out they supply the breathalyzers every driver and navigator in Targa Newfoundland must blow into at the start of each day of the rally.

And there is zero tolerance there — if we don’t blow zero, we don’t run.

marijuana is legal in Canada

ACS’s senior research scientist Dr. Matt Goledzinowski — “Dr. Matt” even to his closest co-workers — took me through a detailed explanation of how marijuana affects the driving task. I hope I do him justice in the limited space I have here! First, a couple of definitions: “cannabis” is the plant; “marijuana” is the drug derived therefrom.

The active ingredient in marijuana is “delta-9-tetrahydrocannabinol,” fortunately and heretofore shortened to THC. It is one of at least 60 cannabinoids identified in marijuana, and the one considered to be the most influential in the effect that Mexican Happy Tobacco has on the human system.

Those weasel words — “at least,” “considered to be,” etc. — are deliberate, because the science of marijuana’s impact on the human body, and especially on the driving task, is still less than perfectly understood.

Not to mention that the altogether-too-free market that has supplied marijuana over the years has meant a distinct lack of quality control.

The potency of a given source, the variability in the composition of the “product” (even province to province), the not-inconsiderable prospect that it might also include things like cocaine, amphetamine, methamphetamine, benzodiazepine and, perhaps more important, the killer fentanyl, make buying off the street a major risk.

Which makes the challenge for marijuana detection devices even more difficult: if you don’t know what you’re looking for, how will you know when you find it?

Research into the effect of alcohol on driving began in the early 1950s, so the science is well known.

Also, there’s a fairly linear relationship between amount and timing of alcohol consumed and level of impairment. Yes, body weight and to a degree gender make a difference, but these variances are reasonably well understood.

ACS and others have developed devices which can measure Blood Alcohol Concentration (BAC), and these are not only scientifically valid, they have stood the tests of both time and our court systems.

With marijuana, we’re just at the beginning, perhaps 10 years into serious research on its effect on the driving task, and we don’t appear to have quite the same degree of certainty as to what degree one’s driving ability is impacted by what level of THC in the blood stream, at least as compared to alcohol.

That said, some effects are predictable.

They can be broken into two categories, physical and psychophysical.

The former typically include body sway and tremors; slower, more deliberate speech; dilated pupils; increased blood pressure, especially among new users; increased pulse rate; red watery eyes; and slower, slurred speech — almost stereotypical “stoner” behaviour.

The latter psychophysical traits are more important to the driving task, and include relaxed inhibitions; difficulty in concentration; disorientation; fatigue; lethargy; short-term memory problems; and particularly critical for driving, altered time and spatial perception.

And maybe worst of all, marijuana impairment can result in a sharpened sense of humour that may make you think this is funny.

It’s not.

Among the challenges for measuring impairment by marijuana is that this drug is generally ingested one of three ways — smoking, vaping (essentially, “smoke-free” smoking), or orally through cookies, brownies and the like. And the impact of these methods varies considerably.

Smoking and vaping have an almost immediate impact, usually within minutes. And, the THC concentration dissipates fairly quickly too, often within a few hours, making detection difficult.

This of course assumes you don’t toke up again.

Edibles have a much lower peak level of intoxication — about a tenth as much as smoking or vaping — and a slower rise — it can take an hour or more after ingestion for the THC to start having the desired effect. This can lead to over-intoxication because users may eat a brownie, nothing seems to happen, so they eat another, and so on…

At least until next year, commercially-produced edibles remain illegal, although apparently you can, um, bake your own.

By the way, medical marijuana is no different from any other form. Pharmaceutically speaking, high is high.

In all cases, drawing a straight time line between time of ingestion and level of impairment is the difficulty for detection of that impairment.

A further complication is that regular use seems to make the impairment on the driving task less serious. No, weed does not make you a better driver. It’s just that you may be less effected than newbies.

Try telling that to the parents of the 5-year-old girl you just ran over.

The last and perhaps most critical issue we face with DWH is finding a reliable method for roadside detection, and for gathering the evidence needed for a conviction. Even with the better-understood science and history behind alcohol impairment, somewhere around 50 per cent of breathalyzer cases that are taken to court result in no conviction.

Roadside weedalyzers (did I just make up a word?) are more expensive, and are only screening devices and not court-admissable proof of impairment, at least so far.

Dr. Matt says that a multi-stage approach to this growing problem is required:


We need roadside drug screening to test oral fluid for THC level. Dr. Matt says that the THC level in the blood or saliva is not necessarily indicative of what is in the brain, but its presence is an indication that further testing needs to be done.

Also, various countries have imposed various limits, which of course complicates everything, especially for the companies like ACS which are trying to make the detectors. Most legal systems tend to set a fair high limit (as we do with alcohol — everybody is impaired at 0.05, but we set the limit at 0.08 to try to make the charge fail-safe, even if that strategy doesn’t seem to work for alcohol, witness the 50 per cent conviction rate in court). For marijuana, a THC count of 8.2 nanograms per mL of blood is about equivalent in impairment level to 0.05 BAC; a THC of 13.1 is about 0.08.

Another complication is that different countries test for different substances. Just about every country tests for THC, but not necessarily for ecstasy (3,4-Methylenedioxymethamphetamine, or MDMA). Why can’t we agree on this?


We need more police officers trained in the Standard Field Sobriety Test (SFST), and in how to use the new weedalyzers.


The saliva taken at the roadside stop must be maintained under strict conditions and taken to a lab for further testing. Also, steps must be taken to ensure the chain of evidence is not broken. The time lapse between the roadside test and the lab test means that the evidence might literally have gone up in smoke.

The early returns on traffic safety in Colorado where marijuana has been legal for six years appear vague. Some reports suggest that the data are inconclusive, others make it seem that the undeniable increase in the state’s traffic deaths in that six-year time period cannot be linked to any other factor, since nothing else has changed to a material degree.

To me, that discussion is meaningless, because we as a society and we as drivers have to accept that any form of impairment — by alcohol, by marijuana, by cellphone use, by fatigue, by aggressiveness, by just plain being stupid — has no place on our roads.

The message is simple. If you smoke, toke, vape or brownie-ize, don’t drive.

marijuana is legal in Canada

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