Defending an impaired driving charge is a complicated affair. There are hundreds of legal nuances to navigate. Often a clients defence comes down to a question of whether the police strictly adhered to the law, or breached protocol. Take for example a persons readings on the intoxilyzer. The presumptions of identity and accuracy mandate that if the intoxilyzer readings were taken within two hours of the time of driving, then they are presumed to be accurate. Moreover, they are presumed to represent the accuseds blood alcohol level at the time of driving even though that is clearly not correct. Afterall, by the time youve blown into the device, almost two hours have passed. This is, in essence, a factual fiction. However, because the law mandates that for this presumption to apply, the readings must have been taken within two hours, the Supreme Court of Canada has held that this is a factual fiction that is reasonable in the circumstances, and thus, the Courts accept it. There are however, further legal mechanisms in place which ensure that these presumptions are not abused. For example, the readings must also have been taken as soon as is practicable. Moreover, the readings must have been generated as a result of a lawful demand. These concepts, of course, are themselves highly nuanced. Too many clients believe that once theyve blown into the intoxilyzer and generated an over 80″, that they have no defence. This is false. It is imperative that anyone charged with an impaired driving charge or over 80″ seek legal advice at the earliest opportunity.