Like alcohol-impaired driving, drug-impaired driving is a criminal offence. Cannabis-impaired driving can result in injury or death for the driver, passengers or others on the road including pedestrians and other drivers. Cannabis:
- impairs judgment
- impairs the ability to react
- increases the chances of being in a crash[i].
The combination of alcohol and cannabis can further exacerbate the impairment.
In 2018, the Criminal Code of Canada was changed to allow possession of marijuana for recreational use but Bill C-46 created new criminal offences for driving while impaired by tetrahydrocannabinol (THC), the active ingredient in marijuana. These new offences are based on the level of THC in a person’s blood within two hours of driving.
- Alcohol
- The prohibited blood-alcohol concentration (BAC) is 80 milligrams (mg) or more of alcohol per 100 millilitres (ml) of blood.
- Cannabis (THC)
- There are two prohibited levels for THC, the primary psychoactive component of cannabis: it is a less serious offence to have between 2 nanograms (ng) and 5 ng of THC per ml of blood. It is a more serious offence to have 5 ng of THC or more per ml of blood.
- Combination of alcohol and cannabis
- The prohibited levels of alcohol and cannabis, when found in combination, is 50mg or more of alcohol per 100ml of blood and 2.5 ng or more of THC per ml of blood.
- Other drugs
- Having any detectable amount of LSD, psilocybin, psilocin (“magic mushrooms”), ketamine, PCP, cocaine, methamphetamine or 6-mam (a metabolite of heroin) in your system within two hours of driving is also prohibited.
- The prohibited level for GHB is 5mg or more per litre of blood since the body can naturally produce low levels of this drug.
A challenge however, is that THC can sometimes be detected in a person’s blood even 30 days after they consumed cannabis.
Impaired Driving Has Tort Implications
While charges are not admissible evidence in tort litigation, criminal convictions are admissible evidence of wrongdoing. Accordingly, any criminal conviction is problematic to the defendant driver.
Where there were no convictions, then the usual rules of negligence will dictate exposure.
An area to consider when mounting a defence is to determine in what format was the cannabis consumed? For example, was it inhaled? Was it in the form of a baked good? A gummy? Was any alcohol consumed? What prescription medication was the driver taking? Different formats have different effects on different timeframes.
When was it was consumed? During the car ride? 2 hours before the car ride? The night before? THC, the psychoactive ingredient, takes time to leave the system and its metabolized carboxyTHC takes even longer – some say it can even take up to a month. Accordingly, any test that is positive for carboxyTHC is arguably only evidence that cannabis had been consumed and not that the driver was impaired by cannabis. Assessing the impact of cannabis is far more complicated than assessing the impact of alcohol. While, alcohol levels are correlated to impairment, the same is not true of cannabis.
Another area to consider once cannabis consumption has been raised is to determine the level of the driver’s impairment. What was the driver’s condition? Were the driver’s eyes bloodshot? Glassy? Pupils dilated? Did the driver have balance issues? Slurred speech? Confusion? Inappropriate responses? Delayed responses? Was the driver tired, sleepy?
A final area to consider is whether the accident was caused by marijuana impairment or by some other factor. For example, was there poor lighting, was there black ice, did another driver do something that triggered the accident, did an animal jump out of the road unexpectedly etcetera. It may be there were other causes to the accident that had nothing to do with impairment.
In order to defend a driver about the effect of the cannabis consumed, witness statements from everyone that had contact with the driver at the scene will be useful to determine whether or not the driver exhibited any evidence of impairment. A toxicologist expert will also be necessary to determine the levels of cannabis and the anticipated effects or lack thereof in the particular circumstances. An accident reconstruction may be considered as well.
This area is developing. There have been criminal trials dealing with impairment, there have been labour decisions, human rights decisions and union arbitrations that are starting to consider and challenge the consumption versus impairment issues. I expect court decisions in the tort context will follow but the litigation process is longer and has been slowed down due to COVID.
[i] Cannabis impairment – Canada.ca
“This article is intended to inform. Its content does not constitute legal advice and should not be relied upon by readers as such. If you require legal assistance, please see a lawyer. Each case is unique and a lawyer with good training and sound judgment can provide you with advice tailored to your specific situation and needs.”
