Defending Impaired Driving Charges

Criminal Code sections 253 to 259

In court the prosecution must prove beyond a reasonable doubt that the driver’s ability to operate a motor vehicle was impaired by alcohol. Testimony of police officers and civilian witnesses is presented to establish that the driver’s ability to drive was impaired.

A proper defence emphasizes inconsistencies in witness testimony, unreliability of evidence and the fact that many of the observations made by the witness may be consistent with the behaviour of a driver who is not impaired in their ability to drive.

Typical Symptoms and Evidence:

Bad Driving:
Although evidence of a bad driving such as swerving, weaving or committing traffic violations may indicate possible impairment, driving such as this takes place on our roads every day with drivers who are not impaired by alcohol consumption.

Odour of Alcohol Beverage:
The scientific consensus is that an odour of alcohol beverage provides no indication of how much alcohol was consumed. The odour is from the flavoring of the drink. Consequently the police cannot reliably estimate how much alcohol a person has consumed or when the drinks were consumed.

Balance Problems:
The police often fail to properly record the type of shoes worn, the road surface or whether the driver has health problems. A deficiency in the evidence can lead to the conclusion that there may be other possible explanations for balance problems aside from alcohol impairment.

Slurred Speech:
Normally the officer has not heard the driver speak prior to the incident and therefore they cannot confirm whether the driver’s speech is affected by alcohol.

“Fail” on an ASD:
A “Fail” result on an Approved Screening Device or Roadside Breath Tester is not admissible in court to prove a driver was impaired. It is also not admissible to corroborate the results of a BAC Datamaster.

Over .08 Charge

The BAC Datamaster:
Although many people use the term “Breathalyzer” to refer to the breath testing machine, in British Columbia the police use the BAC Datamaster C to obtain breath samples to determine the concentration of alcohol in the subject’s blood.
The BAC Datamaster, to be considered reliable, must be operated in accordance with the provisions of the Criminal Code and the operational procedures for the instrument. Although it is a generally reliable machine, there are numerous ways that it can malfunction.

Typical BAC Datamaster Malfunctions

1. Calibration Error - The internal standard is flawed and the results are unreliable.
2. Detector Overflow - The instrument has recorded a result in excess of 600 mg indicating mouth alcohol.
3. Invalid Sample - Mouth alcohol may have affected the sample and the results are unreliable.
4. Interference Detected - The instrument has detected something other than alcohol rendering the results unreliable.
5. Pump Error - The breath tube is obstructed and the results are unreliable.

Every electro-mechanical device can malfunction. A complex device, such as the BAC Datamaster, contains switches, valves a pump and a micro-microprocessor, any of which may fail or malfunction without warning.