Cannabis and Driving

The second quarter data found that about 4.6 million people nationally, or close to 16 per cent of Canadians aged 15 and up, reported using cannabis in the prior three-month period. This was similar to what was reported in last quarter.

The vast majority of respondents — 82 per cent — also said they probably wouldn’t increase their consumption once pot is legalized, which was also relatively unchanged over last quarter.

The latest data was collected from mid-May to mid-June and includes data for the provinces, as well as the territorial capitals.

From the second-story window of the High Life Social Club in Halifax, which is planted discreetly above a café serving all-day breakfast, the owner Chris Henderson points to the bus stop across the street. Until a few weeks ago, it displayed a poster for every departing patron of his cannabis-friendly lounge to see, part of a citywide public-education campaign to prepare for the legalization of marijuana on Oct. 17.

“Drive better on weed?” the poster asked, with a touch of snark, as if you’d have to be on drugs not to know the right answer. As it happens, that’s a question easily answered on a warm Tuesday evening in July, doused in the sweet, skunky perfume of pot, with club members drinking bottled water between hits on a water bong.

Turns out, they think they do. The science, however, begs to differ.

For instance, a 21-year-old High Life regular, and early childhood educator, lounging on a black couch beside a large mural of the caterpillar from Alice in Wonderland, offered an anecdote about a friend who passed her driving test while stoned. (The woman asked not to be identified; her employers, she noted, wouldn’t be so cannabis friendly.) After a day chasing toddlers, she says, smoking a joint helps her focus on the road. Most nights at the lounge, she waits an hour or so, and drives home. Anyway, she insists, if you find yourself too stoned to drive, just pull over and wait 15 minutes to sober up.

A retired telecom technician in his 60s wanders over and joins the conversation. While he now bikes everywhere, he describes driving stoned regularly, with no problems. (Not so with alcohol, he notes, which resulted in an impaired-driving conviction three decades ago, and one accident.) Compared to drinking, he says to general agreement, pot keeps you more chilled out on the road – and less likely to rage at other drivers.

Later in the evening, a 19-year-old engineering students fields questions about his own habits at the counter where chocolate is for sale. He would never drink and drive, he explains, and wouldn’t have driven when he first started using cannabis. But six months in, he figures he knows his limit – today, he says, he wouldn’t take a road trip without a joint. It’s not dangerous, he claims. Among his evidence: He always stop at stop signs.

Collectively, they are candid and amiable – and working hard to convince a stranger that they’re upstanding, clearly aware that their drug of choice suffers from some bad PR.

But none of these assertions are supported in the growing research on cannabis. The sum of all the science – the driving simulations and on-road experiments, the cognitive testing, even the albeit mixed crash-collision statistics – shows clearly that there are far from “zero problems” with driving high.

Marilyn Huestis, a leading American expert who has been studying cannabis for 30 years, including offering advice on driving issues to Canadian policy makers, says that for non-daily users, it takes six hours for the effects of one joint to completely disappear. That’s even if your blood level of THC, the drug’s psychoactive ingredient, is low – an issue that creates additional complications for police testing suspect drivers for legal limits, and a public trying to abide by them. Needless to say, if you’re “too stoned” behind the wheel, don’t expect a 15-minute pause to make you safe. Occasional users perform more poorly than regular users in studies. But even for the pros, the danger exists – though, as it happens, familiar stop signs may be the least of it.

At the same time, research does suggest that people who are stoned are more aware of their impairment than those who’ve been drinking – a self-safety check, undeniably, in their favour. Traffic collision statistics show that driving high increases the risk of a crash or collision, although by how much is still the subject of debate, and the overall risk is nowhere near as high as alcohol. For instance, a French study of drivers in fatal collisions, found those with cannabis in their blood were twice as likely to be found culpable for the crash than sober driver, compared to nine times for those with alcohol in their system.

According to a 2016 study by Norwegian researchers, which updated earlier findings and analyzed 13 international crash-collision studies between 1982 and 2015, cannabis use increases the risk of a crash by about 30 per cent, compared with a sober, attentive driver. Drunk drivers over the legal limit, on the other hand, are more than 600 times more likely to crash, according to report by the National Highway Traffic Safety Administration (NHTSA) in the United States.

In 2016, the NHTSA was also behind what is considered one of the most comprehensive – and controversial – experiments to assess the risk of marijuana and driving. Researchers investigated crashes in real time in Virginia, 24 hours a day for 20 months. They compared the crashed drivers with THC to a control group of drivers stopped in the same location, at the same time as the crash, who agreed to be screened for cannabis. Once researchers adjusted for age and gender – particularly, young and male – and the presence of alcohol, they found no increased risk of collisions compared with drug-free drivers. But despite its great design, there were some flaws in the study’s execution, says Mark Asbridge, the MADD Canada professor in impaired-driving research and prevention at Dalhousie University. The location was near a military base, which regularly tested soldiers for the presence of drugs, an external influence on driving behaviour, and the control-study drivers could refuse to participate, reducing the sample of those with drugs in their system. As with most cannabis studies, there was a delay or problem in getting blood samples, especially for more serious crashes. Even the authors of the U.S. study warned not to interpret their findings – one sample of drivers in one location – to be saying it was safe to drive high.

One of the complications of studying cannabis is how often it is combined with alcohol, a particularly dangerous driving cocktail, the research suggests. In the French study on fatal crashes, for example, drivers who had consumed both alcohol and cannabis were 14 times more likely to be found responsible for the crash when compared with sober drivers – much higher than those who had consumed either drug on its own.

Still, these mixed results suggest why, according to a September 2017 survey commissioned by Public Safety Canada, a hearty portion of Canadians believe that driving high isn’t so bad. Twenty-eight per cent of the 2,132 respondents said they’d driven high, and of those, 17 per cent said the influence of cannabis “posed no real risks.” Nearly one in 10 of all respondents believe cannabis makes a person “a better driver.” For Canadians under the age of 24, risk was perceived to be even lower. In a 2017 large-scale Ontario survey, 8 per cent of teenagers admitted to driving an hour after using cannabis – compared with 4 per cent who said they had driven drunk. The good news is that the driving-high figure has fallen slowly since 2011, when the question was first asked. The bad news is, in the Public Safety survey, 43 per cent of Canadian said they didn’t know how long to safely wait after a joint before driving, with young people more likely to predict shorter wait times.

“We used to say the same thing about drinking and driving. ‘I can have a few drinks and it relaxes me.’ ‘I can have one for the road,’” says Robert Mann, a researcher at the Centre for Addiction and Mental Health. Hopefully, he says, changing attitudes about marijuana won’t take as long. “The clear message is that using cannabis increases your risk of an accident.”

Collision stats clump drivers together to see a highway of cars. They aren’t measuring the safety of individuals, on their own route home. Occasional users appear to score worse when acutely stoned than more frequent users who may have developed a tolerance. (Although, Dr. Heustis notes that the cognitive deficits that result from chronic use may also lower driving skills.) New drivers are likely to be more challenged than veterans. An issue with all marijuana research to date, is that it’s usually focused on smoking the drug, typically at lower THC levels than today’s versions. It’s not clear the difference that newer forms of consumption will have on driving, including edibles, which make a user high more slowly, and can lead to people ingesting too much.

So on a quiet ride on a familiar route, a driver under the influence of cannabis may be able to get home without incident. But driving, as Dr. Heustis notes, is marked by unexpected events – a kid riding their bike into the street, an elderly man dropping his key on the crosswalk, another swerving car. Being high, she says, makes it harder for drivers to compensate for surprises – in simulations, marijuana slows reaction times, divides a driver’s attention and makes decision-making foggy. For example, she says, in lab tests, cannabis users can add a row of numbers as well as a sober person – but throw in a complicated problem and they falter. With driving, Dr. Heustis says, they may be concentrating so hard at the just-getting-it-done task, that a sudden rush of complex information is overwhelming.

Back at the High Life Social Club, Chris Henderson, the businessman with a smoking angel tattoo dancing up his neck and a devil staring from his back, tries to navigate the views of his patrons, and the fears of a worried public. He has a marijuana prescription to deal with chronic pain – he could consume up to six joints a day, although he usually takes much less. Even a few hours after using, he is “100-per-cent confident” he is safe on the road. He’d have no problem taking a roadside test, he says, but he worries about being charged for having THC in his blood, even when he is not impaired.

The new law is “better-safe-than-sorry legislation,” by his way of thinking. “But the most important thing is that the roads remains safe,” he says. “If that means people taking a cab because they smoke a joint, that’s probably not a bad thing.”

Globe and Mail article

Cannabis and driving: Breaking down Canada’s new limits

What’s the new legal limit for cannabis while driving? The government has set 2 nanograms of THC per millilitre of blood as a summary conviction, with up to a $1,000 fine. At 5 ng, a driver would be charged with a criminal offence – similar to the blood alcohol limit of .08 – with a maximum penalty of 10 years in prison. And there’s also a more serious penalty if you are caught with a combined blood limit of .05 and 2.5 ng of cannabis. There is no exception for medicinal users.

How many puffs is that? Unlike alcohol, there’s no clear guideline, and the government hasn’t provided any. It depends on how much and how deeply you inhale, the strength of the cannabis you use and how you consume it, your experience using and your individual characteristics. For edibles, which take longer to take effect, it is even trickier.

What the science says: Research shows that a driver’s THC (the psychoactive ingredient in the drug) blood levels is an unreliable indicator of impairment. While alcohol is absorbed and eliminated in the blood at a linear rate, blood levels of THC fall quickly after smoking and then flatten out. This means people may feel the most high even when their THC blood level is at a very low rate. Since THC leaves the blood so quickly – but remains in the brain for a longer period – a higher legal limit may not capture drivers who are still seriously impaired, especially given the added delay in collecting blood samples. In any event, says Marilyn Huestis, a leading American cannabis researcher, there is no one simple measurement of THC at which everyone using cannabis will be impaired.

How Canada’s law compares: While some U.S. states and countries have zero-tolerance limits for cannabis, Canada’s new legal limits are roughly in line with other jurisdictions, such as Colorado and Washington, where cannabis is legal. Britain, however, allows for a medical defence if the driver can demonstrate they were not impaired.

So what if I use marijuana medicinally? This is a real issue, one that experts have said will probably need to be resolved with court cases. People taking cannabis regularly may have a residual dose of THC in their blood even though they haven’t used recently and are not impaired. Since measuring drugs amounts is complicated, New Zealand’s policing approach, for instance, has emphasized evidence of impairment, and not relied so heavily on blood tests.

What if I get stopped? As before legalization, a police officer may give you a three-part sobriety test – walk the line, balance on one foot, track the finger – if they have reason to believe you have been using cannabis, or any drug that is making you a danger on the road. Police will also be able to administer a saliva test once they are approved and distributed. If you fail those tests, a more detailed interview happens back at the station, but, because THC levels fall so quickly, the new law also allows police to skip right to a blood test.

What’s my best strategy? The guideline recommended by the Canadian Centre for Addiction and Mental Heath – and in research by the National Institute for Drug Abuse in the United States – is to wait at least six hours before driving after a smoking a joint. If you use only occasionally, studies suggest, the effect on your driving will be worse than more frequent users. Be extra careful mixing marijuana with alcohol – when combined, research shows, they may impair drivers much more than either drug alone.

• Rielle Capler, MHA Ph.D. – Candidate, University of British Columbia
• Dan Bilsker, Ph.D. – Clinical Assistant Professor, Faculty of Medicine, University of British Columbia
• Kelsey Van Pelt, BSc MPH – Candidate, Simon Fraser University
• Donald MacPherson Executive Director, Canadian Drug Policy Coalition (CDPC) Adjunct Professor, Faculty of Health Sciences, Simon Fraser University

Download PDF – Click Here

Objectives. To evaluate motor vehicle crash fatality rates in the first 2 states with recreational marijuana legalization and compare them with motor vehicle crash fatality rates in similar states without recreational marijuana legalization.

Methods. We used the US Fatality Analysis Reporting System to determine the annual numbers of motor vehicle crash fatalities between 2009 and 2015 in Washington, Colorado, and 8 control states. We compared year-over-year changes in motor vehicle crash fatality rates (per billion vehicle miles traveled) before and after recreational marijuana legalization with a difference-in-differences approach that controlled for underlying time trends and state-specific population, economic, and traffic characteristics.

Results. Pre–recreational marijuana legalization annual changes in motor vehicle crash fatality rates for Washington and Colorado were similar to those for the control states. Post–recreational marijuana legalization changes in motor vehicle crash fatality rates for Washington and Colorado also did not significantly differ from those for the control states (adjusted difference-in-differences coefficient = +0.2 fatalities/billion vehicle miles traveled; 95% confidence interval = −0.4, +0.9).

Conclusions. Three years after recreational marijuana legalization, changes in motor vehicle crash fatality rates for Washington and Colorado were not statistically different from those in similar states without recreational marijuana legalization. Future studies over a longer time remain warranted.

For more information follow LINK … Recreational Marijuana Legalization Driving

Should Canadian lawmakers reconsider the amount of THC a driver can have in their bloodstream before legalizing cannabis in 2018?

Now here’s a study Canadian lawmakers should read as they consider Bill C46, which seeks to amend the Criminal Code with respect to drug-impaired driving.

A study recently published in the American Journal of Public Health has found that states with legalized recreational cannabis do not have a greater rate of car accident deaths than states where cannabis is illegal.

Conducted by doctors and researchers from the University of Texas-Austin and Rice University, the study compared car accident fatalities in Colorado and Washington, where cannabis is legal, to similar data from eight control states where the drug is still prohibited.

Researchers used a federal fatality reporting system to determine the annual number of fatalities from motor vehicle accidents over six years, between 2009 and 2015, in the 10 states.

By comparing year-over-year changes, they found that the number of fatalities did not increase after recreational cannabis was legalized in Colorado and Washington, and was consistent with the number of deaths in the eight control states.

“This is the first time researchers have actually looked at the real-life effects to see if there have been any major population changes in injuries on the road after marijuana was legalized in these states,” lead study author Jayson Aydelotte told KTVU News in Austin last month.

In both Colorado and Washington, drivers with five nanograms of active tetrahydrocannabinol (THC) per millilitre in their bloodstream can be prosecuted for driving under the influence. Some marijuana lobbyists claim this is far too low, as frequent cannabis users can have residual amounts of THC in their bloodstream well above five nanograms—and for days after consumption.

Others argue the amount is too high, especially because the numbers determined are based on policy, instead of evidence of impairment.

Bill C46 currently outlines a limit of just two nanograms of THC per millilitre.

To put that in context, Canadian Olympian Ross Rebagliati won the gold medal for snowboarding in 1998 with more than eight times than what the federal government has suggested, at 17.8 nanograms per millilitre.

Story from the Straight … Cannabis and Driving