Opinion: 3 of Canada's biggest blunders in impaired driving laws after cannabis legalization

Jul 24 2019, 10:23 pm

Written for Grow by Sarah Leamon, a criminal defence lawyer and founder of Sarah Leamon Law Group. Sarah specializes in impaired driving offences and cannabis law.

The legalization of cannabis brought about some rather unexpected legal changes. 

Bill C-46 has been widely referred to as the companion bill to Bill C-45, which legalized cannabis, and it made wipe-sweeping amendments to the criminal laws around both alcohol and cannabis-impaired driving offences. 

And some Canadians are already feeling the burn.

With questionable technology being deployed and individual Charter rights being trampled, here are the three biggest problems with Canadas new impaired driving rules.

Questionable roadside saliva testing technology

Our federal government has approved two different oral fluid screening devices for use by police officers throughout this country. These devices can be used to detect the presence of THC in driver’s saliva, but can’t do much more than that.

The Draeger DrugTest 5000 and the Abbott SoToxa were both introduced amid ample scrutiny. And with good reason.

Relatively untested in the field, these devices come with a host of potential problems that could result in serious consequences for innocent drivers. 

For example, these devices have a limited operational temperature range, which means that they cannot generate reliable results in extremely hot or extremely cold environments. In fact, the Draeger has a temperature range between 400°C and 40°C.  So, if the temperature dips any lower, the device may generate either a false negative and false positive reading. 

This means that a person who just smoked a joint could test negative for THC while another person, without any THC in their system at all, could test positive, weather dependent. 

Is that a risk you’d be willing to take? 

But the biggest blunder by far is the fact that the devices cannot actually detect cannabis impairment in a driver. They do nothing more than test for the mere presence of THC in the subject’s saliva. 

That’s right…these drug screeners can’t actually determine if you’re high. 

They tell us nothing about how the subject is presenting, their level of impairment, or whether or not they are even affected by THC in any way whatsoever… which seems like a pretty massive oversight when the goal of using them is to detect and remove impaired drivers from our roadways. 

This also stands in stark contrast to alcohol screening devices, which can provide a relatively clear insight into just how drunk a person is, depending on the result of their breath test. This is because the level of alcohol present in a person’s bloodstream is more-or-less indicative of their level of impairment. 

Alcohol, which is water-soluble, moves through the human body at a relatively consistent rate, unlike THC, which is fat-soluble. The differing nature of these compounds means that developing a scientific test for cannabis impairment based solely off bodily samples may be next to impossible. 

But in spite of their scientifically questionable status, the Draeger and the SoToxa were introduced to help officers in the course of investing drug-impaired driving offences. 

In the old days, officers had to rely on good old fashion police work over technology. 

They used standardized field sobriety tests in order to access impairment. These tests involve a number of divided attention task coordination tests, such as the one-legged stand and the walk-and-turn test. Depending on how the driver performs, they will either pass, and be let go, or fail, and be arrested. 

While police still have standardized field tests at their disposal, chances are high that drug testing devices will eventually become their preferred investigatory tool…so long as our courts don’t strike them down first.  

Per se limits for THC

The introduction of per se limits for drivers with THC in their bodies is perhaps the most mind-boggling legal change to impaired driving laws post-legalization. 

But what does it mean?

Simply put, a per se limit creates an offence, per se, regardless of really anything else, including whether the person in question is actually impaired, or even affected by, an intoxicating substance. 

The presence of a prescribed level of a particular substance – in this case, THC – in the driver’s bloodstream constitutes the basis for the offence itself. Nothing more is needed. 

This means that a driver without any symptoms of impairment, who is not actually impaired and who is not posing any risk to public safety, can be charged and subsequently convicted of a criminal offence in this country. The basis for this conviction would simply be the act of being behind the wheel and testing positive for a certain level of THC in the body. 

And what’s more – that level is extremely low. 

Just two nanograms of THC, which is widely considered to be a therapeutic dose, is enough to attract a charge resulting in a $1,000 fine and a criminal record. The penalties only go up from there. Drivers who have more than five nanograms in their bodies could face a maximum sentence of ten years in prison, even if they weren’t impaired. 

If that sounds unfair, it’s because it is. 

It may also be unconstitutional, in spite of the fact that per se provisions for alcohol-impaired driving are well-established. 

Again, the crux of the problem boils down to the fundamental difference between alcohol and THC.

Alcohol is different than drugs, including THC, as it moves through the human body at a relatively consistent rate. It does not remain in the body after the effects have worn off. This means that a person who tests positive for a criminal level of alcohol in the bloodstream is, in fact, impaired by alcohol. 

The fat-soluble THC compound is completely different. It can stay in the body for three to four weeks after consumption, meaning that a driver can test positive for THC weeks after the psychoactive effects have completely worn off. 

Targeting safe and sober drivers, who simply have THC in their systems, does nothing to protect the public against the dangers of impaired driving or to destigmatize cannabis use post-legalization. It only serves to advance harmful narratives about the dangers of cannabis, while criminalizing responsible cannabis users. It also has the potential to disproportionately target medical cannabis users. 

Hopefully, it will only be a matter of time before this law goes up in smoke. 

Mandatory roadside alcohol testing

Perhaps the biggest blunder in our new cannabis-impaired driving laws has nothing to do with cannabis at all. 

It has to do with alcohol. 

Since December 2018, police officers can demand random, mandatory breath samples from drivers on the roadside to test for alcohol impairment. They have absolute power to do this regardless of whether they suspect the person to have been drinking or not. 

Critics have pointed out how this type of arbitrary police power could lead to corruption. It may lead to increased instances of racial profiling and unlawful detention, for example. 

It is also a considerable erosion of our constitutionally-entrenched rights, including the right to be free from unreasonable search and seizure, which is something we should always be wary of. 

But on top of that, it a major departure from our previously well-established drinking and driving laws, which required police to form a reasonable suspicion of alcohol in the body in order to detain a driver and demand a bodily sample for analysis. 

Simply detecting an odour of liquor on a driver’s breath was enough to support such a suspicion in most jurisdictions across Canada. This is a pretty easy thing to do for most police officers, who have special training for such things, and can be accomplished within a matter of seconds after encountering a driver. 

Even though the burden in forming the grounds to ask for a breath sample was relatively low, it was still very important. 

After all, it acted as an essential procedural safeguard on individual rights and liberties by ensuring that sober drivers would not be unfairly targeted by police. 

The decision to change the law and create a mandatory breath testing regime in relation to alcohol, was done under Bill C-46, which was – of course – largely focused on cannabis-impaired driving. 

But alcohol has nothing to do with cannabis…right? 


The numbers are out and there is no actual evidence that cannabis legalization leads to an increase of alcohol-impaired driving. 

In fact, there has been nothing to indicate that rates of either alcohol or cannabis-impaired driving have increased in any manner whatsoever since the legalization of cannabis in this country. Police forces have consistently reported no changes in drunk or high driving behaviours, and recent statistics seem to support their claims. 

So, while some public interest groups may insist that random alcohol breath testing is necessary to enforce safety standards in the largely unchartered and unknown territory of legal weed, the cold, hard facts seem to point elsewhere. 

We simply don’t need this law to stay safe, and it’s about time to weed it out.

Guest AuthorGuest Author

+ Grow
+ News & Policy