Drinking and Driving
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Common Defences
Overview
Numerous defences can be raised on a charge
of Over 80. A few of the most common are described below and on
the pages that follow. Availability of any defence depends on
the facts of your case.
Breath readings inaccurate
You can raise a reasonable doubt about whether your blood alcohol concentration (BAC) was over the legal limit with evidence that you did not drink too much and by demonstrating that that the breath instrument was malfunctioning or operated improperly. You will also need to show that but for the malfunction or improper operation, your readings would have been within the legal limit.
To mount this defence at trial, you will need a toxicologist (an
expert on the body's absorption and elimination of alcohol) or a report from one. The toxicologist can
calculate your BAC based on your weight and the amount and time
of alcohol consumption. (Hiring a toxicologist for
trial will likely cost over a $1,000; a report can be obtained for much
less or from the Centre of Forensic Sciences in Toronto for free.)
Unless the judge finds the evidence about
how much you drank unreliable, your testimony will throw doubt
on the readings obtained by police. In assessing your evidence about alcohol consumption, the judge cannot take into account your breath test results, however high. This follows from a December 2005 decision of the Supreme Court of Canada (see paragraph 43).
Were you over the limit?
Were you over the legal limit at the time of the alleged offence? Use the Calculator to approximate your blood alcohol level.
On an Over 80 charge, the Crown must prove your
BAC was over the legal limit at the time of driving. But because
police do the breath instrument test only afterward, the Criminal Code
presumes the result - the lower of the two readings obtained from
the breath samples - reflects your BAC at the time you are stopped.
The presumption applies only if the tests are
started within two hours. If the first test is carried out more than two
hours after the time of driving (or care or control), the Crown
will need a toxicologist to calculate your BAC at that time. If
the Crown fails to bring one or a report from one to your trial,
the Over 80 charge cannot be proven.
Last drink defence
If the breath instrument readings are slightly over
80 and you guzzled a drink just before being stopped, you may
have a "last drink" defence. As it takes time for alcohol
to enter the bloodstream, a toxicologist may be able to testify
you were under 80 at the time of the stop because the alcohol
had not yet been fully absorbed. The last drink defence is very effective because you do not have to
question the reliability of the breath instrument results. However, your evidence must also show that the breath instrument results accurately reflect your BAC at the time of the tests.
Disclaimer: The material on this site is not intended as legal advice. It merely conveys general information on legal issues commonly encountered by persons facing criminal charges in Canada. If you are charged with an offence, you should contact a criminal lawyer.
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