Science 24 – Drinking and Driving ws
Name: ________________________ Date: _____________________
Read the information below and answer the questions that follow.
Alcohol and Driving
Alcohol remains a major factor in collisions and fatalities. Almost one quarter of the
fatal accidents in Alberta involve alcohol, a depressant that is legal for anyone in Alberta
18 years or older to consume.
Driving and BAC Levels
It is legal to drive with a blood alcohol concentration (BAC) of as much as 0.08 mg/mL,
but that does not make it a good idea. It is quite possible to be impaired without being
―over the limit.‖ As an example, a person may have six drinks within 1.5 hours and be
under the legal limit but still quite drunk.
The many skills involved in driving are not all impaired at the same BAC. For example,
a driver’s ability to divide attention between two or more sources of visual information
can be impaired by a BAC of 0.02 or lower. However, it is not until a BAC of 0.05 or
more that impairment occurs consistently in eye movements, tolerance for glare, visual
perception, reaction time, certain types of steering tasks, information processing, and
other aspects of psychomotor performance. More demanding driving tasks are impaired
by even low doses of alcohol.
Compared with drivers who have not consumed alcohol, drivers with a BAC between
0.02 and 0.04 are 1.4 times more likely to be in a fatal single-vehicle crash. For those
with a BAC between 0.05 and 0.09, the risk is 11.1 times higher; 48 times higher with a
BAC between 0.10 and 0.14; and 380 times higher with a BAC of 0.15 or more!
How the Body Deals with Alcohol
When people have a drink, the alcohol is absorbed directly into the bloodstream through
the stomach and small intestine. The more someone drinks, the more alcohol is absorbed,
and the higher the BAC climbs. Given enough time (typically 30–90 minutes) alcohol is
distributed evenly throughout the body.
Like most things we eat or drink, alcohol must be broken down and eliminated. It takes
much longer to eliminate alcohol from the body than it does to drink it.
Most alcohol is destroyed by a process called oxidation. The oxidation of alcohol breaks
it down into carbon dioxide and water. More than 90 percent of the alcohol is oxidized in
the liver. The rest is eliminated, unchanged, through the lungs and kidneys. The liver’s
capacity to break down and dispose of alcohol is limited — it takes just under two hours
for the liver to break down a standard serving of alcohol (see note on percentages below).
As people drink, alcohol is absorbed into the bloodstream and BAC rises quickly and
peaks. If they stop drinking, the BAC levels off. It can remain level for as long as an
hour or two because alcohol is entering the bloodstream at the same rate as it is
eliminated. BAC will then drop steadily by approximately 0.015 per hour. It is
important to remember that a BAC can rise much more quickly than it falls.
BAC can easily be measured in a person’s breath by using a Breathalyzer. As blood
flows naturally through the lungs, the alcohol molecules pass into the air in the lungs and
is expelled as the body breathes. When a person blows into a Breathalyzer, the
concentration of alcohol in the blood can be measured as accurately as a blood test.
Penalties for Impaired Driving
The penalties for impaired driving are severe, reflecting the gravity of the offence.
Penalties usually become increasingly severe with repeated convictions. In addition,
judges have considerable discretion in setting terms of probation, and offenders may be
required to seek treatment for alcohol abuse, perform community service, or provide
compensation to victims.
If, while driving impaired, someone is involved in a crash that results in an injury or
death, the driver may be charged with impaired driving causing bodily harm or impaired
driving causing death. These are serious charges that carry severe penalties including
In Canada, a police officer can ask for a breath sample from a motorist as long as there is
a ―reasonable suspicion‖ that the motorist has consumed alcohol prior to driving. If the
roadside screening device registers a reading of ―fail‖, the motorist is arrested and
transported to a police station where they are tested on a Breathalyzer or Intoxilyzer
In Canada, a person is required by law to provide two suitable breath samples, based
upon the opinion of the breath technician (RCMP or police officer). If a suspect refuses,
they are charged with ―refusing to provide a breath sample‖, an offence which carries the
same penalties as the offence of impaired driving. This applies to the roadside demand as
well, and such offences carry the same penalties as impaired driving. Therefore in
Canada, refusing to provide a breath sample will only complicate the legal problems a
person creates for themselves by choosing to drink and drive.
Figure 13.4 (next page) shows the penalties for driving with more than 80 milligrams of
alcohol in 100 millilitres of blood or greater — that’s a BAC of 0.08, the legal limit.
Meaning of Percentages
The percentages provided in the textbook refer to the alcohol level of a standard drink,
not the BAC. This means that hard liquor has an alcohol content of 40 percent, wine 11
percent, and beer four percent — though most Canadian beer contains more than five
percent alcohol. No matter what kind of beverage, a standard alcoholic drink (―one
serving‖) contains the same percentage of alcohol. That means that a serving is equal to
one beer or one glass of wine or one ounce of hard liquor (shooter, or single mixed drink
– i.e., rum and coke).
impaired driving • Minimum fine of $600 for first offence.
driving with a BAC over 0.08 • Minimum one year license suspension.
• Second offence results in 14 days imprisonment and a two-year
• Subsequent offences result in 90 days’ imprisonment and a
three-year license suspension.
failing to provide a breath or blood sample • Imprisonment and a one-year license suspension.
without a reasonable excuse • Maximum penalty for first, second, or subsequent offences:
$2000 fine, six months to five years imprisonment, and three-
year license suspension.
impaired driving causing death • Maximum penalty of life imprisonment and a ten-year license
impaired driving causing bodily harm • Maximum penalty of 14 years’ imprisonment and a ten-year
driving while prohibited or suspended • Maximum penalty of $2000 fine, six months’ imprisonment, and
a three-year license suspension.
1. How many fatal accidents in Alberta involve alcohol? _________________________
2. Explain why it is not a good idea to drive after you have been drinking even if your
BAC is below 0.08. ____________________________________________________
3. What skills are impaired at a BAC of 0.05? _________________________________
4. As a person’s BAC increases, they are ______ likely to be in a fatal single-vehicle
5. How does alcohol get absorbed into the bloodstream? ________________________
6. (a) How is alcohol destroyed by the body? __________________________________
(b) What products are made when alcohol is destroyed? _______________________
(c) Where does this reaction occur in the body? ______________________________
7. How long does it take for the body to break down one serving of alcohol?
8. How does a Breathalyzer measure alcohol in your body? _______________________
9. What penalties might a judge give someone who has been charged with drinking and
10. (a) What happens if you refuse a breath test? ________________________________
(b) What penalty does ―refusing to provide a breath sample‖ carry? ______________
11. What is one serving of alcohol? ___________________________________________
12. (a) What is the penalty for impaired driving causing death? _____________________
(b) Besides the legal penalties for impaired driving causing death, what personal
consequences would you have to deal with if you killed someone after drinking
and driving? ______________________________________________________