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Motor Vehicle Accidents

Are there problems with Canada’s new drug-impaired driving laws?

...some fear the changes go too far and may result in additional litigation.

In recent years, major changes have been made to Canada’s impaired driving laws by way of Bill C-46.  The new impaired-driving laws set the legal limits for THC (the primary psychoactive component of cannabis) while operating a motor vehicle. Under the new laws, cannabis cannot be consumed by drivers or passengers while driving. If a driver is over the legal limit of THC, major penalties can follow.

Impaired driving is a serious offense and is the number one criminal cause of death in Canada. In 2017, there were more than 69,000 impaired driving incidents reported by the police, including almost 3,500 drug-impaired driving incidents. Although drug-impaired driving is already an offence in Canada, Bill C-46 creates legal limits for THC concentration levels in the bloodstream and allows the use of roadside screening devices.


The penalty associated with drug-impaired driving depends on the concentration of the substance in a driver’s system, just like blood alcohol levels. Under the new legislation, there are two concentration limits for THC. If a driver is over two nano-grams of THC per millilitre of blood, the result is a summary conviction. If a driver is over five nano-grams of THC, then the driver can be criminally charged. Penalties for the offence vary depending on factors such as the THC concentration, if it is a driver’s first or a repeated offence, or whether an impaired driver has caused bodily harm or death to another person.

What Bill C-46 Does

Bill C-46 effectively rewrites the Criminal Code provisions concerning impaired driving. The law gives an officer the discretion to demand a roadside saliva test. The approved device is the Draeger DrugTest 5000, commonly referred to as the “drugalyzer”. In about five minutes, this device will indicate if it detects THC in the saliva sample. This device does not measure the level of THC in a driver’s bloodstream. Instead, it simply indicates the presence or absence of THC by a positive or negative reading.

Officers may also choose to conduct a Standardized Field Sobriety Test rather than, or in conjunction with, the saliva test. If a driver fails the Sobriety Test, a drug recognition officer may conduct additional tests at a secondary location to further determine if the driver is impaired.

Potential Issues with Bill C-46

The changes in the legislation are meant to improve the efficiency of prosecuting cases, by taking away possible defenses from the accused driver. However, some fear the changes go too far and may result in additional litigation.

The science behind the saliva testing devices is still being refined. This has the potential to result in more challenges for Canada’s Courts. Recent studies suggest the test device, approved by legislatures, has a 15% chance of returning a false positive result,  where the driver tests positive, but has not consumed cannabis and has no trace of THC in their system. A false positive result gives an officer the right to take an individual into custody for further testing, which may include a blood test.

Furthermore, the length of time an individual can be detained is problematic. The saliva test in combination with a Field Sobriety Test can take up to 20 minutes. Then, a blood test can take 2-3 hours to administer and process the results. The law pertaining to alcohol says an individual’s rights are suspended while a police officer is collecting a breath sample for alcohol. However, administering a breathalyzer test only takes minutes. The breathalyzer also provides a blood alcohol level reading instantly, unlike with the drugalyzer which only indicates the presence of drugs in a driver’s system, not the concentration.

The longer time of detainment for the impaired drug process coupled with the unknowns surrounding some of the technology that has been approved by the legislature is likely to receive Charter scrutiny and challenges in the Courts.

At MacGillivray Law, we help injury victims across Canada pursue justice and fair compensation for their injuries. If you’ve been injured in an accident caused by impaired driving, contact us today at 1-888-434-0398 for a free consultation.

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