Frequently Asked Questions About Pot & Driving

The information presented here dates from a CPHA project on Pot and Driving concluded in 2006. References to laws may not reflect current legislation, and more recent research may augment the information presented here. This section is not being updated, and is presented here in recognition of its ongoing general utility and informativeness.

Introduction

On November 21, 2005, the Canadian Public Health Association, with funding from Canada’s Drug Strategy, Health Canada, launched a Pot and Driving campaign (www.potanddriving.cpha.ca) to raise awareness among young Canadian drivers and passengers of the risks of cannabis-impaired driving. Campaign materials include:

A poster of airplane pilots smoking up with the campaign message, “If it doesn’t make sense here, why does it make sense when you drive?”
10 Questions (to provoke thought and dialogue)
The thinking behind the questions (to encourage discussion)
These FAQs (to inform the discussion)

These FAQs provides information on a range of issues related to cannabis use in the context of driving. It draws on up-to-date, relevant studies and surveys, insights given by key informants from Canada and several other countries, and the opinions of young Canadians who took part in focus groups held in several locations across the country.

1. Why a pot and driving focus?

What do we mean by ‘pot’?
We use the word ‘pot’ in our materials to refer to any drug derived from the cannabis plant, including marijuana (which is made from the leaves and buds), as well as hashish and hashish oil (made from plant resin). We chose this word because it is short and easy to say; more importantly we chose it because focus group participants were unanimous in saying that along with the word ‘weed’, ‘pot’ is the most common word used to refer to cannabis in both English and French Canada.

Canadians between the ages of 14 to 25 have one of the highest rates of pot use in the world. Many young Canadians who use pot see it as a mild, mainstream drug with no significant negative consequences. While most young drivers and passengers have little tolerance for alcohol-impaired driving, they commonly regard pot and driving as risk free.

Recent research on pot is showing that it can play an important role in road vehicle crashes, especially when combined with driver inexperience and difficult road conditions. Road accidents are often the result of a combination of factors and pot can be one of them.

Pot is the most popular drug used by Canadians 14 to 25 years-of-age, after alcohol and tobacco. Drug-use surveys indicate that the rate of driving under the influence of pot surpasses that of alcohol. Alcohol has been the subject of impaired-driving awareness efforts for several decades and tobacco is not a risk for driving. It is time to put the focus on pot.

2. How does cannabis affect driving ability?

Driving skills are affected in specific ways when a person has consumed a certain amount of pot. This impairment increases with the amount of THC (the compound that gives pot its high) a person has in his/her system. While drivers have been found to do certain things to adapt to their impairment, like slowing down, this attempt to compensate does not eliminate the risks of driving high.

It has long been established that pot affects tracking ability, meaning that drivers who are under the influence of a certain dose of THC have been found to have a harder time following their lane. Pot reduces a driver’s ability to perceive changes in the relative speed of other vehicles and to adjust his/her own speed accordingly.

Pot has been found to increase the reaction time needed to respond to an emergency decision-making task, such as adapting to changes in speed of the vehicle ahead or to the vehicle’s brake lights. A driver needs to notice something in order to respond to it and that has to do with the driver’s attention. Because pot disturbs concentration and short-term memory, a driver has a harder time being attentive to events and situations on the road that can have important consequences for road safety.

3. Who drives under the influence of pot?

What do we mean by ‘driving’?
When we use the phrase ‘driving a vehicle’ we are referring to the use of any kind of motor vehicle, including cars, trucks, motorbikes, ATVs, planes, motorboats and snowmobiles. We generally use the word ‘driving’ to imply the use of both on and off-road vehicles. We do not wish to suggest that off-road driving is less of a concern when it comes to drug use.

Several student surveys in Canada have found a high rate of pot use among students in high school, with the rate increasing with age/grade. Male students have a higher rate of use than female students. The likelihood that a person will drive high depends on how frequently they use pot. Daily pot users have the highest rate of driving high while occasional users have the lowest rate.

Cannabis use by Canadian adolescents is reported to be among the highest in the world. The 2002 Nova Scotia Student Drug Use Survey found that 22% of students surveyed used marijuana in the month before the survey, while 5% used it every day. The 2002 Alberta Youth Experience Survey indicated that cannabis use by Aboriginal youth (52%) was almost twice that of non-aboriginal youth (27%). One in five Ontario high school student respondents in the 2003 Ontario Student Drug Use Survey reported driving one hour after using cannabis during the past six months.

Drugged driving is not isolated to young Canadians or to Canadians who use illegal drugs. Older drivers are more likely to drive impaired by prescribed medications; younger drivers are most likely to drive while affected by illegal drugs, including cocaine and pot. It is young, male, frequent pot users, who are most likely to drive high.

4. Why focus on mainstream teens?

Surveys conducted in Canada and in countries such as Australia have shown that driving under the influence of cannabis is rare in the general population but common among cannabis users, a group concentrated in those 14 to 25 years-of-age. For this campaign, we decided to target mainstream youth since data indicates that the rate of cannabis use is approaching the rate of alcohol consumption among youth in Canada. Pot has become mainstream.

We spoke to several groups of young Canadians 15-25 years-of-age about their experiences with pot and driving. Generally, older participants were convinced that driving high was not a problem and said they were unlikely to change their minds about doing it. Participants who were not yet driving or were anticipating learning how to drive appeared to be more open to the suggestion that mixing pot and driving, like mixing alcohol and driving, could put them and their passengers at risk. So we decided the campaign should focus on mainstream Canadians 14-18 years-of-age.

5. Who is likely to be a passenger of a driver who is high?

Studies have found that a person’s likelihood of being a passenger of a driver who has used pot within an hour or two of driving, or uses it while driving, increases with high school grade. Gender does not seem to be a factor, although our focus group participants did provide some indications that female passengers may be more likely to be a passenger with a boyfriend who is high than a female friend.

6. How long after using pot are driving skills affected?

Cannabis impairs driving skills most severely during what is known as the acute phase, which typically lasts for up to 60 minutes after smoking. This is followed by post-acute (the phase after the acute one) and residual phases. The residual phase is 150 minutes or more after smoking, during which impairment subsides rapidly. The degree of impairment during the residual phase depends on the amount of THC consumed. After smoking a so-called typical dose (about 20 mg) of THC, the residual phase lasts 2-3 hours.

7. What about ‘burnout’?

Burnout is roughly equivalent to the ‘hangover’ associated with alcohol. Very little is known about the effect of ‘burnout’ on driving, although some focus group participants flagged it as a significant issue for driving. Some even suggested they felt safer driving high than driving during burnout. Since burnout is characterized by fatigue, studies of the effect of fatigue on driving might be applied to burnout.

8. Does the dose influence the risk?

What is drugged-driving?
If your ability to drive a motor vehicle is affected because you have taken a drug, a combination of drugs, or drugs and alcohol (which is also a drug although it is usually referred to separately), you are drugged-driving. A number of medications prescribed by doctors as well as some over the counter remedies are known to affect a person’s ability to drive safely. Several illegal drugs are also known to affect driving skills.

As is the case with alcohol, risk increases with dose. However, regular users have been found to experience less effect from the same dose. Unlike alcohol, pot’s THC concentrations can vary significantly from batch to batch.

Since cannabis is illegal and unregulated, there is no standardized consumption limit as there is for drinking alcohol and driving. In experimental research, drivers are given what would be considered an ‘average’ dose of THC and then observed as they perform a number of driving tasks on the road under controlled conditions. For the sake of safety, these tests cannot put drivers in situations that would likely lead to accidents.

So the variation of pot’s THC content, the widely varying effects of pot on individuals, the different contexts in which it is used, and the difficulty in testing dose in actual driving conditions lead to the conclusion that the relationship between dose and risk is not entirely clear.

9. Can a drug that is used to treat disease also affect driving?

Although pot is usually thought of as a recreational drug in North America, it is also used for medical purposes. Drugs that can help reduce the symptoms of a disease can also affect a person’s ability to drive safely. That is why some prescription drugs come with warnings not to drive for a certain amount of time after taking them.

10. How does pot compare with alcohol as a threat to road safety?

Why the term pot and driving?
Phrases like alcohol-impaired driving, drunk-driving, drinking and driving or driving under the influence of alcohol (DUIA) are well known. Equivalent terms referring to drug use and driving-- including drug-impaired driving, drugged driving and driving under the influence of drugs (DUID)--are less well known, although that is changing.We have chosen to use more informal phrases such as driving high, mixing pot and driving or simply pot and driving.

In Canada, driving under the influence of alcohol is widely regarded as both dangerous and socially unacceptable. The evidence to date supports the claim that alcohol is still one of the most important contributors to crash risk injury or death. The increasing evidence of the contribution of drugs other than alcohol to road crashes, whether they are consumed with alcohol or by themselves, has led to a number of efforts to increase awareness of the potential road safety hazards of these drugs. The perception that pot is relatively risk-free when compared to alcohol may help explain why recent drug use surveys in Canada have found that the rate of driving under the influence of pot surpasses the rate of driving under the influence of alcohol among young drivers and passengers.

11. Why not adopt a law enforcement message?

Law enforcement has played an important role in changing attitudes about alcohol-impaired driving. However, fear of being caught and prosecuted for driving high seems not to be a significant concern for many young people.

Focus group participants indicated that parents could be a deterrent if for no other reason than they usually control the keys to the car. Focus group participants also indicated that it is tougher to fool parents: “When I’m driving high I’m more afraid of my mom because cops have no way of telling. Whereas if my mum says ‘You’re high’, I’m not going to say ‘I’m not’ because I know she’s not going to believe me.”

12. What does Canadian law say about drugs and driving?

It is the effects of pot on driving—not the legal status of pot—that makes its use illegal both before or while taking control of a motor vehicle.

Article S. 253 of the Canadian Criminal Code says that: “Everyone commits an offence who operates a motor vehicle or operates or assists in the operation of an aircraft or railway equipment or has the care or control of a motor vehicle, vessel, aircraft or railway equipment, whether it is in motion or not, (a) while the person’s ability to operate the vehicle, vessel, aircraft or railway equipment is impaired by alcohol or a drug.”

In the Canadian Criminal Code, laws on impaired driving are distinct from laws that say whether it is legal or not to produce, sell or use a particular drug. In other words, the fact that a drug is legal or illegal has nothing to do with the issue of driver impairment. As an example, it is legal to drink alcohol for age-of-majority Canadians but it is illegal to drive while impaired by alcohol.

13. Can law enforcement officers identify and charge drivers who are impaired by cannabis?

What is THC?
THC is the primary psychoactive compound found in cannabis. A psychoactive drug is one that alters brain function, resulting in temporary changes in perception, mood, consciousness, and behaviour.

As noted above, current law makes it a criminal offense to drive while impaired by cannabis and other drugs. The federal government is considering tabling Bill C-16, which would amend the Impaired Driving section of the Canadian Criminal Code in order to allow police officers to require drivers to undergo a Standardized Field Sobriety Test if the officer believes the person is driving under the influence of a drug. If a driver fails the sobriety test, the officer would have reasonable grounds to believe the driver has committed a drug-impaired offence and can require the driver to submit to a Drug Recognition Expert (DRE) evaluation at the police station. Police departments across the country have begun to train officers to conduct DRE assessments.

If a person fails these procedures, police would have reasonable grounds to demand a sample of bodily fluids, whether blood, urine or saliva. Charges can only be laid after the presence of drugs in bodily fluids is confirmed by laboratory analysis. A driver who refuses to complete the sobriety test or provide bodily fluid samples would be criminally charged, as is the case for drivers who refuse sobriety test and breathalyzers when they are suspected of driving while impaired by alcohol.

14. Will changes to the Criminal Code relating to cannabis possession and use (Bill C-17) affect laws and law enforcement relating to cannabis-impaired driving?

Under the legislative changes proposed in Bill C-17, possession and use of cannabis will remain illegal, but anyone found to have small amounts of cannabis for personal use would only be fined. If these proposed changes to the Criminal Code become law, driving high will likely be more, not less, subject to penalty than it is today. For example, possession of 15 grams or less of cannabis will be punishable by a fine of $150 for an adult and $100 for a person under the age of 18. However, where aggravating factors such as driving a car exist (even if the driver is not high), the fine would be $400 for an adult and $250 for a person under the age of 18.