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Impaired Driving Offence


  • This charge is found under section 253(1)(a) of the Criminal Code.
  • In order to be found guilty, the Crown must be able to prove beyond a reasonable doubt that a person’s ability to operate a motor vehicle was impaired by alcohol or a drug.
  • Currently, it is rare to be charged with impaired driving by a drug and it is often difficult for the Crown to prove such a charge beyond a reasonable doubt.

How Does the Crown Prove It

Typically, the Crown will call witnesses who will testify as to the various physical symptoms and driving behaviour demonstrated by the accused in and around the time of driving, such as:

  • Bad driving (ie. weaving)
  • A motor vehicle accident
  • Odour of alcohol on the breath (this alone does not mean the accused is impaired, but merely that she or he potentially had been drinking at some point)
  • Bloodshot and/or watery eyes (this alone which means little)
  • Unsteadiness, balance problems, walking problems, co-ordination problems
  • Slurred speech etc…

(See How Can Kruse Law Firm Win an Impaired Driving Trial?)

Difference between impaired and exceed/over 80

  • Impaired driving is a completely separate charge from driving while having in excess of 80 mg. of alcohol in 100 ml. of blood (commonly referred to as an ‘exceed’ or ‘over 80′ charge).
  • The exact wording of an exceed or over 80 charge is found under section 253(1)(b) of the Criminal Code.
  • The difference between an impaired driving and an exceed charge is illustrated as follows: A person who has never had a drink in his or her life, might be driving while “impaired” or even drunk after 3 or 4 drinks. They would then be charged with impaired driving because they are weaving all over the road, slurring, exhibiting balance problems and possibly other signs of impairment. However, they might blow under the legal limit of 80 mg. of alcohol in 100 ml. of blood. On the other hand, a chronic alcoholic might wake up every morning over the legal limit, but never be “impaired” because they never show signs of impairment such as slurred speech etc.


Impaired driving is a completely separate and distinct charge from an exceed or over 80 charge, and really has nothing to do with the actual reading on the intoxilyzer or breathalyzer because everyone has different tolerance levels. For example, an alcoholic could easily have very high blood alcohol readings and appear completely sober. On the other hand, a novice drinker might appear to be drunk at very low levels of blood alcohol.

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