Impaired Driving
Impaired driving is the criminal offence, under section 320.14(1)(a) of the Criminal Code, of operating a conveyance while the accused's ability to operate it is impaired by alcohol, a drug, or a combination. Unlike the related over 80 offence (BAC at or above 80 mg/100 mL), impaired driving requires proof of actual impairment — and the impairment can be by any substance, not just alcohol.
Mass Tsang's DUI lawyers have decades of combined experience defending impaired driving charges. For more, see our blog post on how to fight an impaired driving charge.
Proving impairment
The Crown can prove impairment through: police observations (driving pattern, balance, coordination, speech, odour of alcohol or drugs); standardized field sobriety test (SFST) results; Drug Recognition Evaluation (DRE) opinions; toxicology results; the accused's own statements; and any other circumstantial evidence. Impairment to any degree — "slight" impairment — is enough. Unlike some U.S. jurisdictions, Canada does not require gross impairment.
Alcohol vs. drug impairment
Alcohol impairment cases typically involve a combination of breath evidence and behavioural observations. Drug impairment cases turn more heavily on the SFST, the DRE, and toxicology. Cannabis impairment in particular has been the subject of new statutory thresholds and prosecutorial frameworks since legalization in 2018; per se limits of 2 ng/mL and 5 ng/mL of THC in blood operate alongside the impairment offence.
Penalties
Impaired driving carries mandatory minimum penalties identical to those for over 80: first offence — $1,000 fine and 12-month prohibition; second offence — 30 days jail and 24-month prohibition; third or subsequent offence — 120 days jail and 36-month prohibition. Causing bodily harm raises the maximum to 14 years; causing death raises it to life imprisonment.
Collateral consequences
An impaired driving conviction triggers: mandatory ignition interlock; mandatory Back on Track program completion; significantly increased insurance premiums; a permanent criminal record; restrictions on entry to the United States; and immigration consequences for non-citizens.
Defences
Defences include: Charter challenges to the stop, screening demand, arrest, or right-to-counsel implementation; absence of impairment in fact (observations consistent with non-impairment); medical conditions producing impairment-like symptoms (diabetes, head injury, fatigue); challenges to SFST or DRE evidence; identification issues; and procedural defects in the investigation.
Related glossary terms
