There has been a lot of talk on social media throughout the province over the past week about the laws surrounding driving and cannabis. Much of the discussions have centred on the zero-tolerance policy outlined in the provincial Traffic Safety Act for the presence of THC in the person who is behind the wheel.  

Constable Maralee McSherry is with the Weyburn Police Service and is also a Drug Recognition Expert.  

“What they’re saying is that if you have any detectable level with our devices, which detect 25 nanograms (of THC) in your saliva, that you will be issued a driver’s license suspension,” Cst. McSherry clarified. The roadside test is also not testing for impairment, but just the presence of THC at that level.  

The suspensions range from a three-day suspension for a first offence, all the way up to 18 months, depending on the number of offences, and whether or not there are children present in the vehicle.  

A roadside test for cannabis, unlike alcohol, can’t be done without reasonable suspicion. If the officer suspects a driver may have cannabis in their system, they can take a number of steps. This includes a standard field sobriety test, or they can use the oral swab test, which is done with either the Cetoxa or the Drager machine the officer has with them.  

Studies on the detection of cannabis in saliva have shown for recreational users the level of THC in their saliva generally drops to below levels that were detectable with the test faster than someone who is a habitual user, however, the data also showed a large variability. In both test groups in one study, THC was found at levels over 25 nanograms around 12 hours after use.  

Those who are against the zero-tolerance policy have argued that habitual users of cannabis could test positive even if they are not impaired, or those who use cannabis for medical purposes could test positive when they are just treating it as a medication, not as a recreational drug. 

“A lot of individuals will think, well, I take cannabis for my medical needs,” Cst. McSherry said. “There are a lot of people out there that have to take things like fentanyl for their medical needs, and most people would say that operating a vehicle or conveyance while using fentanyl would be dangerous.” 

Cst. McSherry added those who are habitual users of cannabis will often show signs of impairment up to 24 hours after use. The user, though, may not necessarily feel like they are showing signs of impairment, as they feel like they are sober, since it is normal to them. This is when the drug recognition comes in.  

Some of the signs a person could be impaired by cannabis include having altered time and distance perception, alteration in thought formation, body tremors, eyelid tremors, bloodshot eyes, and relaxed inhibitions.  

There was one piece of advice Cst. McSherry had for everyone, though. 

“If you think that there’s any possibility that you’re impaired by any substance, never get into a vehicle (to drive), and that also includes prescription medication.