This is interesting, however, there is still no definitive way of determining if the person is drugged or not. The police have no way of measuring the quantity or the drug influence you are under. I asked my daughter who is a nurse in Canada, and she confirmed that they are still looking for a way of determining the factual evidence of a persons' supposed intoxication.

Driving while impaired by a drug

People impaired by a drug are not safe drivers because of the effects of drugs on the body. Impaired drivers put everyone at risk including others on the road, pedestrians and their own passengers.
Driving impaired by a drug is also illegal and is subject to serious penalties including the potential for life imprisonment if there is a death. On April 13, 2017, we proposed legislation that would strengthen impaired driving laws and help better protect you from drug-impaired driving.
Learn more about the risks of driving impaired by a drug.

On this page

• Risks while driving impaired by a drug
• Drugs that contribute to collisions
• Teenagers, drugs and driving: advice for parents
• Get help

Risks while driving impaired by a drug

When you drive a vehicle, your brain needs to be alert and focused. Even small amounts of a drug can affect your ability to drive safely. Different drugs act on your brain in different ways, but almost all affect your:

• attention
• judgment
• motor skills
• reaction time
• decision-making skills
• balance and coordination

Serious accidents can easily happen when you drive while impaired by a drug. Many drivers who have collisions may have both drugs and alcohol in their system.
Police can test drivers for alcohol-impairment using breath tests. Police across Canada trained as drug recognition experts have the tools and ability to determine if a person is impaired by drugs.

Drugs that contribute to collisions

Studies of vehicle accidents around the world show that the drugs most commonly found in drivers involved in accidents (after alcohol) include:

• cannabis (marijuana)
• opioids
• amphetamines
• benzodiazepines
• cocaine

Despite popular myth, driving after using cannabis is not safer than driving drunk. Cannabis impairs you differently than alcohol but it still impairs.

Performance becomes even worse if drivers combine drugs, such as cannabis, with alcohol.
Prescription drugs, when used properly or when abused, can also impair driving. Legal drugs, such as opioid pain relievers and benzodiazepines (prescribed for anxiety or sleep disorders) can affect a person's ability to safely control a moving vehicle. People who are prescribed these medications are warned by their pharmacist against operating any machinery, including vehicles, for a certain time after taking them. People who abuse these medications to get high may not even be aware of this danger.

Teenagers, drugs and driving: advice for parents

Many car crashes involving teenagers are caused by inexperience and poor judgment. When these factors are combined with alcohol, cannabis or other drugs, the results can be tragic.
According to the 2014-15 Canadian Student Tobacco, Alcohol and Drugs Survey:

• 5% of students in grades 7 to 12 reported having driven a vehicle within 2 hours of cannabis use
• 15% of students in grades 7 to 12 reported being a passenger in a motor vehicle driven by someone who had used cannabis in the previous 2 hours

Parents play a vital role in teaching young people to drive responsibly. That means teaching them not to drive impaired by alcohol or drugs. There is no safe limit for young drivers, since even one drink or a small amount of a drug can affect them.
Parents may wish to:

• discuss how drugs and alcohol can impair driving ability, affect perceptions, and slow reaction times
• remind teens that it is always illegal to drive impaired by alcohol or drugs
• make it clear that using alcohol, cannabis or other drugs when driving is dangerous
• discuss the dangers of getting into a car with a driver who has been drinking or using drugs
• model safe driving behaviour by never driving any vehicle impaired