Early in 2019, a Nova Scotia woman named Michelle Gray, who routinely used medical marijuana to manage her multiple sclerosis, was subjected to a roadside saliva test. It showed, that she still had some THC—the psychoactive ingredient in cannabis—in her system.
She advised she hadn’t had any for seven hours prior to driving and passed a 12 step sobriety test but nonetheless, the police impounded her car and suspended her driver’s licence for seven days. She also got stuck with a $253 tow / impound bill.
But the question is: Was she impaired?
Law enforcement agencies across Canada are struggling with this question even now, months after legalization has come into effect. Here’s what you need to know, if you’re an occasional or even habitual consumer of cannabis in Ontario:
The Federal Government Doesn’t Run Law Enforcement In Ontario
While the federal government has approved the use of the roadside saliva testing machine, called the “Drager DrugTest 5000”, it is up to the provinces, within the jurisdictions of local law enforcement, to decide whether or not to use them.
Ottawa, and several other cities, have opted not to use them, questioning their accuracy. For one thing—and the manufacturer stipulates this themselves—the machine can fail below 4 degrees Celsius.
Since this is Canada, we have to assume that there will be a high failure rate 6 months of the year! In addition, a study of this exact machine, published in the Journal of Analytical Toxicology, noted that it is prone to providing a high number of false-positive or false-negative results.
But most important of all, while the machine can detect whether or not the person has THC in their system, it cannot detect their level of impairment, if any.
According to medical authorities including the Mayo Clinic, traces of THC can remain in your system, particularly if you are a chronic user, for up to 30 days, as it is stored in fat cells.
“A person may have a blood level of THC [that’s] high, but not be impaired — this is because they develop tolerance. This doesn’t happen with alcohol,” said Prof. Andrea Furlan, an assistant professor of medicine at the University of Toronto, as well as a senior scientist at the Toronto Rehabilitation Institute. (Source)
So what’s the point of the test? The point of the saliva test is to decide whether or not further investigation into the person’s possible impairment—like a blood test at the police station—will be needed.
Can You Be Charged With Impaired Driving As A Result Of A Saliva Test?
In Ontario, the short answer is no.
The Ministry of the Attorney General has stipulated that police units in Ontario cannot rely on saliva detection devices and their results in criminal impaired driving investigations.
The only thing the saliva test results can be used for is to determine whether the person has THC in their system, not whether or not they are impaired as a result. A blood test is still required for a criminal charge to be laid.
Police across the country are trained to use the Standardized Field Sobriety Test (SFST), which requires a person to walk in a straight line, stand on one leg while completing a mental task and complete an assessment involving eye movement.
This, in conjunction with a saliva test, can lead an officer to suspect impairment. If that’s the case, you may have to submit to a blood test at the nearest police station.
Exceptions To The Use Of The Saliva Test As A Foundation For A Charge
There are a couple of exceptions to the above statement about the use of saliva tests in criminal investigations of impaired driving:
There is a zero-tolerance policy for drivers under the age of 21, drivers with a G1, G2, M1 or M2 license, commercial vehicle operators, including anyone using a road building machine.
If you are in one of these categories and are found to have ANY THC in your system, you will face a license suspension and a fine for the first offence. Second and third offences carry penalties that can include criminal charges and mandatory education programs, as well as longer suspensions and higher fines.
If You Consume Cannabis, Don’t Drive
Your level of impairment and how long it could last will vary tremendously from person to person, depending on the strength and THC levels in the cannabis, whether or not you are used to consuming it and have therefore built a tolerance and other factors, like whether you’ve combined pot and alcohol.
While alcohol tends to make people more aggressive behind the wheel, taking more risks, cannabis and its relaxing effect can result in the user having a delayed reaction time and an overall lack of coordination.
The Canadian Society of Forensic Science stated that it is very difficult to pinpoint what level of impairment you might experience so, like drinking, the best solution is to avoid driving at all if you’re planning to consume cannabis.
Plan for another way home, take a taxi, or stay with a friend, but if there is even a chance you might be impaired, don’t get behind the wheel.
What’s In The Future For Roadside Testing?
A lot of options are on the table, including a tablet based simulator program that will test levels of impairment by evaluating a person’s reaction time to situations like a pedestrian jumping out in front of the ‘simulated’ car and so on.
For Michelle Gray, she is taking her case through the court system to the Supreme Court, in the hopes of clarifying the laws around cannabis impairment so that others don’t have to go through what she did.
The outcome of her case could set a new standard across the country, but for the time being, it’s best for you, and for others on the road, to avoid driving at all after consuming cannabis. If you have an accident where someone—yourself included—is injured becomes that much more complicated if drugs are involved.