Impaired driving in Canada
In 1982 62% of drivers killed in crashes had been drinking. This lead to the
public becoming less tolerant of impaired driving. Behavior changed and
impaired driving deaths fell dramatically.
In spite of progress, 37.5% of drivers test positive for alcohol and 81% of
alcohol positive cases have a blood alcohol concentration greater than 80
However, there is a new problem emerging in the impaired driving field—
drugs. Drugs are different and present more complex issues, they come with
many research challenges which account for shortcomings in our knowledge
of drug impaired driving.
Why is drug impaired driving so complicated?
Drug impaired driving is so complicated because there are many different
drugs, many different populations of users.
Moreover, poly-drug use can be difficult to detect because the physical effects
differ depending on what drugs you have taken.
Unlike alcohol testing, drug testing requires urine samples, oral fluid
samples, or blood samples.
These complexities require a different approach to enforcement and
detection of drug-impaired drivers
Magnitude of impaired driving problem
Self-reported driving after alcohol and cannabis use
In 1988, 24.6 percent of Canadians reported driving after alcohol use and
2.1% reported driving after cannabis use.
By 2009, only 9% of Canadians reported driving after alcohol use and 2.8%
reported driving after cannabis use.
So, we see a huge decrease in driving after using alcohol, and a slight increase
in driving after cannabis use. Driving after drinking according to age
This study shows that as you get older, you are less likely to drive after using
cannabis. However, it also shows that from 16-24 you are most likely to drive
At age 25, you are much less likely (almost half as likely) to drive after
By age 45, you are only a bit more likely to drive after drinking than you were
Generally, a decrease in driving after drinking/cannabis use as age
2008 BC Roadside Survey
This survey involved administering breath tests and oral fluid tests on
random drivers between 9pm and 3am.
10.4% tested positive for drugs. Of those that tested positive, 50% tested
positive for cannabis, 39% tested positive for cocaine, and 8.1% tested
positive for alcohol.
Drug and alcohol positive cases by gender
Drug and alcohol positive cases are more likely to involve men than women,
and are more likely to involve men using drugs other than alcohol.
Drug and alcohol positive cases by age
Generally, a decrease in drug and alcohol positive cases among higher age
Fatally injured drivers in Canada
37.5% of fatally injured drivers tested positive for alcohol
32.7% tested positive for drugs. Of that 32.7%, the most common drug was
CNS depressants and the least common were CSN stimulants.
It is important to note that the presence of a drug does not necessarily mean
that the driver was impaired or that the drug contributed to the crash.
Drug evaluation and classification program
This is a systematic, standardized 12-step procedure to document the extent
of someone’s impairment and to identify the category of drug responsible.
This process involves observations, tests of divided attention, and clinical
indicators. This process ends with a demand for a urine, oral fluid, or blood sample to be
tested for drugs.
The 12 steps of a Drug Evaluation and Classification exam
Breath alcohol test
This is a review of the subject’s breath alcohol concentration
Interview with the arresting officer
This is an interview with the arresting officer to get a sense of the
circumstances surrounding the subject’s arrest
This is a preliminary examination to assess, in large part, whether the subject
is suffering from an injury or a condition unrelated to drugs
The Drug Recognition Expert (DRE) looks for telltale signs of impairment in
the subject’s eyes. Some of the things he is looking for are horizontal gaze
nystagmus, pupil size, lack of convergence, etc.
Divided attention tests
The DRE administers tests like the one leg stand, and walk and turn tests.
The DRE looks at things like the subject’s pulse, blood pressure, and body
temperature for signs of drug intoxication
The DRE looks at pupil size, and pupil reaction to light
The DRE examines the subject’s muscle tone because some drugs can cause
muscles to become rigid
The DRE looks for signs of injection sites