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Study on cannabis and driving questions zero tolerance limits for THC

While in France the Paris Court of Appeal judge because overconsumption of cannabis abolished the judgment of a murderer and taking cannabis can make you criminally irresponsible. Expert in Canada explains why he considers zero tolerance limits for THC to be "excessive and scientifically no founded". According to a recent study published in Canada, people who used a driving simulator showed no signs of impaired driving one day after smoking cannabis, although they still tested positive for THC.

The research has implications for workplace laws and rules that require no trace of THC, what Scott Macdonald, a retired professor at the University of Victoria, calls " unscientific "

I consider one of the biggest myths about cannabis the fact that hangover effects are measurable 24 hours a day, ”he says. “When people smoke cannabis, they are only weakened for a short, very short period of time. You might have THC in your blood, but you're not a danger. ”

Researchers at the Center for Addiction and Mental Health in Toronto gave participants 10 minutes to smoke cannabis at the level of their choice, and then tested it in a driving simulator.

As they were allowed to control their own consumption, the blood levels of THC in the group varied. They ranged from zero to 42 nanograms per milliliter, almost 10 times the legal limit for driving.

How long does cannabis stay in your body?

The driving simulator scenario provided for a nine-kilometer journey on a section of country motorway signposted at 80 km / h, with some simple problems to solve, such as a slow vehicle.

Immediately after smoking, the THC group showed signs of impairment, badly centering the imaginary car in its lane and driving inappropriately slowly.

But in other tests 24 and 48 hours later, they still had detectable THC levels and behaved normally in the driving simulator.

“We found significant evidence of differences in driver behavior, heart rate and the effects of self-reported drugs 30 minutes after smoking cannabis, but… we found little evidence to support the residual effects,” said wrote the authors.

This study shows that, like alcohol, the impairment of cannabis disappears at the latest one day after consumption, if not much sooner.

However, THC can continue to appear in tests long after a disability has ended, unlike alcohol, which would cease to be detectable as the disability subsides.

"Biological tests are not helpful in identifying people who pose a security risk," said Macdonald. “What we have left are behavioral symptoms. We are still working on developing tests to assess whether a person who uses cannabis poses a safety risk. It's hard to do.

“Cannabis is not in the same class as alcohol, in terms of safety risk. Alcohol is much worse. ”

Several provinces prohibit young or new drivers from having a detectable THC level.

In Ontario, for example, drivers who violate a zero tolerance rule for THC are subject to a three-day suspension, a fine of $ 250 and a reinstatement fee of $ 281 for the first offense. The penalties increase for repeat offenders.

Saskatchewan has taken what may be the strictest approach in Canada: New drivers in the province, regardless of THC level, face 60-day license suspension, three-day vehicle seizure and four demerit points.

The Ontario Ministry of Transportation supports this policy.

“In October 2018, the Canadian Society of Forensic Science released a report that cannabis impairment begins almost immediately and can last up to six hours or more, depending on factors like the THC level and how of which it is consumed, wrote spokeswoman Kristine Bunker in an email response.

“Since the effects of cannabis vary, there is no way to know exactly how long it takes to be able to drive safely.”

Zero tolerance rules work as a roundabout way to ban cannabis use by young people, says Jenna Valleriani, Executive Director of Hope for Health Canada.

Most young people drive and have daily responsibilities, like school and work, so when we have data showing that drivers would exceed limits 24 and 48 hours after use, it does little to make our roads smoother. safe and deserves a reassessment, ”she wrote in an email exchange.

“Driving is a privilege, but at the same time, cannabis is legal today, and young people older than the age of access should be able to use the weekend and drive a full day later to get to at work or at school without risking drunk driving.

Across Canada, some police services have effectively banned cannabis from their own members. Montreal police have the right to consume in their spare time, provided they report to work “fit for service”. But Toronto police and the RCMP prohibit officers from consuming less than 28 days before they report to work, while Calgary police officers are not allowed to consume at all. (Since THC can be detected up to 28 days after consumption, these policies are more or less the same.)

The Toronto and Calgary police unions opposed the policy when it was announced, with Toronto calling it "dishonest" and "arbitrary", and Calgary saying its members said " definitely not really happy with the idea that my employer is telling me what I can and can't do with legal stuff on my own time. ”

"I think the 28-day bans are excessive and not based on science, especially now that cannabis is legal," says Macdonald. “If cannabis was illegal, I could see it from this point of view. It is not scientifically founded that they pose a risk to the public if they have used cannabis in the past 28 days. ”

Toronto police are ready to reconsider the 28-day ban, said spokesman Const. Victor Kwong wrote in an email.

“(The rule) was developed in a thoughtful manner and based on sound advice and evidence, taking into account the essential role that members play in ensuring the safety of the workplace and the community. We will continue our research and explore this procedure. If at some point new scientific data or new research leads us to reassess our processes, we will do so. ”

A British Columbia labor arbitrator recently issued a decision against TransLink, the Vancouver area transit company, about how she handled an employee's positive THC test.

David Solomon, a trainer, was forced to undergo drug tests twice a month for a year, despite a doctor's opinion that his use of cannabis was not a problem. Solomon had to call the test service every day to find out whether he would take a test that day or not, and go to a laboratory to be tested if the answer was yes.

The military allows certain members to use cannabis at certain times, depending on their employment. Some, such as divers, aircraft crews, submarine crew members and drone operators, are subject to a 28-day ban similar to that of the more restrictive police force.

“Many jobs - generally those who are security sensitive - have adopted a zero tolerance policy, but as cannabis becomes more integrated into society, we will need to consider policies that reflect this change and will adopt a better understanding of cannabis and its effects, ”wrote Valleriani.

"Some jobs require drug and alcohol testing as a condition of employment, but that raises the question of how workplaces can manage the risk of impairment without having a precise measure of it."

The study was published this week in the Journal of Drug and Alcohol Dependence. Macdonald was not involved in this.

During the study, a placebo group received smoking-free THC joints, but it turned out that participants knew very well whether or not they had used THC, more than 90 percent of the two groups having indicated precisely in which group they belonged.

During the study, a placebo group received smoking-free THC joints, but it turned out that participants knew very well whether or not they had used THC, more than 90 percent of the two groups having indicated precisely in which group they belonged.

When asked if they would be comfortable driving a real car, 80% of participants in the placebo group answered yes, compared to less than 30% of participants in the THC group.

"This is the most important sample of all the samples I know of," said Macdonald of the 91 study participants.

CAMH and Health Canada: principal author of the studye.

Former Supreme Court of Canada decision says sobriety field tests cannot be used in court against person charged with driving under the influence of cannabis

A decision of the court decided that the police cannot testify in court regarding the so-called "results" of the field sobriety tests used when determining a person's blood alcohol level. However, officers are still allowed to testify about a person's characteristics during a routine check. The decision has declared that it would not be appropriate for these tests to be used to determine whether a person is under the influence of cannabis, citing the lack of scientific consensus on the effectiveness of sobriety tests on people who have used cannabis.

The SJC now says based on science, the standard field sobriety test that we use for alcohol, which we have used in the past for marijuana, does not match.

In the decision, the Supreme Judicial Court wrote that jurors are allowed to use common sense when examining the evidence. The decision also does not exclude officers from performing field sobriety tests, but they say they cannot answer the question definitively.

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