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Drug-Impaired Driving

Effects of Psychoactive Prescription Drugs on Driving

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Driving under the influence of alcohol and other drugs remains the most prominent factor contributing to serious collisions in Canada. While the devastating consequences of alcohol-impaired driving are well known, the harm of driving under the influence of drugs is gaining more attention. The percentage of Canadians drivers fatally injured in vehicle crashes and testing positive for drugs (40.0%) now exceeds that of drivers testing positive for alcohol (33.3%). 

​​There is one set of penalties for all impaired driving, whether from drugs or alcohol. Drug-impaired drivers can be detected by police officers who are trained and certified as Drug Recognition Experts. Such experts evaluate a driver’s behaviour and can request a blood, urine or oral fluid sample for testing. Read our policy brief on oral fluid drug screening​.​

Addressing drug-impaired driving

The Drug Evaluation and Classification (DEC) program is a 12-step systematic, standardized procedure authorized for use in Canada to evaluate suspected drug-impaired drivers. The DEC protocol provides a valid, reliable evaluation of impairment as a result of drug use. Read our policy brief on the program.

“Per se” laws for alcohol establish a legal limit for blood alcohol content. If a driver has more than the per se limit of blood alcohol, then the driver is judged to be impaired. Per se limits for drugs should be considered, although this is more challenging as the limits need to be agreed upon for each drug, including prescription drugs. Read our policy brief on per se limits for drugs​.

Psychoactive prescription drugs can also contribute to impaired driving. Although the ways in which drugs affect the body and brain vary, the effects will have the same overall result: a decrease in the brain’s ability to process information and respond by movement, skills relevant for driving. This decrease has negative effects on driving ability and increases the risk of a car crash. Read our report on The Effects of Psychoactive Prescription Drugs on Driving