Canadian Centre on Substance Use and Addiction


Alcohol- and drug-impaired driving is a major contributor to fatal road crashes in Canada. Youth are the largest group of drivers who die in crashes and test positive for alcohol or drugs. Other areas of concern are the possible increases in cannabis impaired driving among adults and the potential for some prescription medications to impair driving ability. The research section summarizes current information about the effects of alcohol, cannabis and other drugs on driving, as well as risks associated with youth and impaired driving.

Alcohol-Impaired Driving

Alcohol-Impaired Driving

Driving under the influence of alcohol can result in deadly consequences. Although these types of fatalities have declined in recent years, in 2014 (the year for which most recent data are available) more than one in four fatally injured drivers (28.4%) tested positive for alcohol. Alcohol-impaired driving remains an ongoing public safety concern and major contributing factor to road crashes in Canada.

Driving with a blood alcohol concentration over 80 milligrams of alcohol in 100 millilitres of blood (80 mg/dL or .08) is a criminal offence in Canada. In an effort to reduce impaired driving harms, most provinces have lowered acceptable blood alcohol levels to 50 mg/dL (.05).

Canada has zero tolerance alcohol and drug policies for young and novice drivers because they are a high-risk population for alcohol-impaired driving. For more information on impaired driving laws, please view Policy and Regulations.

In an effort to reduce the risks and harms of alcohol-impaired driving, the Government of Canada introduced mandatory alcohol screening in December 2018. This new law allows law enforcement to demand a breath sample from drivers without needing reasonable suspicion that the driver has consumed alcohol.

Cannabis-Impaired Driving

Cannabis-Impaired Driving

Cannabis-impaired driving increases the risk of vehicle collisions causing serious injury or death. With the recent legalization of cannabis, there has been increased focus on cannabis use among Canadians, how often people drive after using cannabis, and the costs to society resulting from crashes associated with using cannabis.

In 2017, 19% of Canadians aged 15 to 19 years and 33% aged 20 to 24 years reported using cannabis, which are both higher than the national reported use of 15% for Canadians. However, youth are not the only concern. People 25 and over who reported using cannabis in 2015 increased by 10% in 2017 (see Canadian Tobacco, Alcohol and Drugs Survey). Increasing cannabis use among Canadians and misperceptions about the impact of cannabis on driving mean that some people might choose to drive when they could be impaired. According to the 2018 Canadian Cannabis Survey, 43% of people who used cannabis within one month of the survey reported driving within two hours of consuming it. More concerning, 33% reported using cannabis and alcohol together within two hours of driving.

Along with the significant impact on people’s lives, collisions associated with cannabis use are costly. In 2012, cannabis-attributable costs were estimated at $1.09 billion in Canada, with almost two-thirds of all fatality-related costs being associated with young adults aged 16 to 34. Further:

  • In 2012, cannabis-attributable collisions accounted for roughly 75 fatalities, 4,407 injuries and 7,794 victims of property damage;
  • 58% of the costs are related to fatalities; and
  • 16 to 34 year-olds represented 32% of the population but 61% of cannabis-attributable fatalities. This group also represents 59% of the cannabis-attributable injuries and 68% of the people involved in cannabis-attributable property damage only collisions.

For more information about cannabis, resources and tools to address cannabis use, and its impact on health, see Cannabis.

Drug-Impaired Driving

Drug-Impaired Driving

Various types of drugs can impair driving and potentially result in serious injury or death. These drugs includes prescription medications (e.g., opioids, sedatives), over-the-counter medications (e.g., sleep aids, cold medications) and illegal drugs (e.g., cocaine, heroin). These drugs can also negatively affect cognitive and motor functions, including those essential to operating a vehicle. In addition, drugs used in combination with other drugs (e.g., alcohol and cannabis) can multiply impairing effects. For more information, please see the Effects of Drugs on the Body and Driving handout.

Additionally, roadside impaired driving tests in Canada found that:

  • In 2014, 42.4% of drivers tested positive for drugs compared to 28.4% testing positive for alcohol;
  • In some Canadian provinces, cannabis is the most frequently detected psychoactive drug in drivers; and
  • Other detected substances, such as opioids and sedatives, are a growing concern.

Drug-Impaired Driving Laws

To address concerns with the legalization and regulation of cannabis and to reduce harms associated with drug-impaired driving, Canada and all Canadian jurisdictions have amended their drug-impaired driving laws. To help detect drug-impaired drivers, the Canadian government approved a new portable oral fluid screening device for use by law enforcement. More information on updated laws, various tools and their legal implications can be found in Policy and Regulations.

Detecting Drug-impaired Drivers

The potential for impairment by drugs can be assessed through driver behaviours, oral fluid screening devices and other means. For more information about detecting drug-impaired drivers, please see Policy and Regulations.

Cannabis and Driving

The potential for impairment by drugs can be assessed through driver behaviours, oral fluid screening devices and other means. For more information about detecting drug-impaired drivers, please see Cannabis-Impaired Driving.

Prescription Medications and Driving

Prescription medications with psychoactive properties are a risk to drivers. Many Canadians might not be aware of the potential impairing effects of different types of medications. Individuals taking medications must ask their doctor or pharmacist about potential risks to driving.

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