Road Safety

Drug Impairment

Driving while impaired by drugs, including prescription and non-prescription medications and illicit drugs, is illegal in Canada. Police identify drug-impairment in drivers by administering roadside drug recognition evaluations. Under the Criminal Code of Canada, drivers found guilty of drug-impaired driving face the same penalties as those convicted of alcohol-impaired driving.

Drugs come in many forms and have a wide range of possible effects and side effects. Some drugs create a physiological or psychological dependence, or both. Drug use can drastically impair your driving ability and significantly increase the likelihood of a vehicle collision. Never mix drugs and alcohol - even in small quantities.

Drugs' effects can be short-term in nature or can stay in the body over long periods of time. Drugs can accelerate or decelerate your physiological system and can distort your perceptions.

Prescription drugs

Tranquillizers, antidepressants, sleeping pills and similar drugs can affect driving ability even if taken in the prescribed dosage. If you drive while impaired by any medication, you can be charged with impaired driving and face the same consequences as if you were impaired by alcohol. Discuss the possible effects of any medication with your doctor or pharmacist.

Illegal drugs

Illicit drugs may cause hallucinations, hostility and aggressiveness in addition to dulling normal thought processes and slowing down eye-hand coordination. If you are found to be driving while under the influence of illegal drugs, you will be charged with impaired driving.

Key differences between drug and alcohol impairment

Drug impairment presents some unique challenges that are different than alcohol impairment:1

  • There are a large number of available substances or combinations of substances—both legal and illegal.
  • The effects on the body are different and change over time.
  • It can be more challenging to measure the level of impairment.
  • Drugs do not have a clear dose-response relationship, which makes it complicated to figure out exactly how impaired someone truly is.

The statistics in Canada

  • Results of alcohol and drug tests performed on drivers who died in motor vehicle crashes in 2008 in Canada reveal that 37 per cent were positive for drugs compared to 41 per cent who tested positive for alcohol.2
  • The National Highway Traffic Safety Administration survey shows that, despite reductions in alcohol-impaired driving, the instances of drug-impaired driving appear to be on the rise. The survey found that nearly one in four drivers tested positive for at least one drug that could impair driving ability.3
  • A Canadian report on impaired driving found that in 2011, 12.6 per cent of those ages 15-24 admitted to driving after taking cannabis, compared to 10.7 per cent who reported driving after drinking.4
  • In Ontario, a 2009 study of students found that 17 per cent of drivers in Grades 10-12 reported driving a vehicle within one hour of using cannabis.5
  • When asked to rate the dangers of specific driving behaviours, Canadians thought that driving after taking drugs such as cocaine or methamphetamines was “extremely dangerous” and voted it second only to texting while driving.6

Further reading

The following links provide information about drug-impaired driving and its consequences:

Additions Foundation of Manitoba

The Canadian Centre on Substance Abuse


1 Source: Traffic Injury Research Foundation 2014
2 Source: Canadian Association of Road Safety Professionals 2012
3 Source: The Insurance Journal 2015
4 Source: Canadian Centre on Substance Abuse 2011
5 Source: Traffic Injury Research Foundation 2011
6 Source: CCMTA National Public Opinion Survey 2014