DUI & Impaired Driving Defence

How We Fight DUI Charges in Ontario

Impaired driving is the single most commonly charged criminal offence in Canada. If you have been charged with impaired operation, operation with a blood-alcohol concentration at or over 80 mg (commonly called “Over 80”), or refusal to provide a breath sample, you are facing a criminal charge that carries a mandatory minimum penalty — including a criminal record, a fine, and a driving prohibition. There is no discharge available for impaired driving offences, which means a conviction always results in a criminal record.

The good news is that impaired driving cases are among the most technically complex in criminal law, and there are often strong defences available.

The Offences and Penalties

The Criminal Code (Part VIII.1) sets out several impaired driving offences:

Impaired Operation (Section 320.14(1)(a))

Operating a motor vehicle while your ability to do so is impaired to any degree by alcohol, a drug, or a combination. This offence is based on observable signs of impairment (driving pattern, physical symptoms, behaviour).

Over 80 (Section 320.14(1)(b))

Operating a motor vehicle with a blood-alcohol concentration (BAC) equal to or exceeding 80 mg of alcohol per 100 ml of blood within two hours of driving. This is a “per se” offence — the number on the breathalyzer is the offence, regardless of whether you appeared impaired.

Refusal (Section 320.15)

Failing or refusing to comply with a lawful demand to provide a breath sample (roadside screening device or approved instrument) without a reasonable excuse. Refusal carries the same penalties as an Over 80 conviction.

Mandatory Minimum Penalties

• First offence: $1,000 fine and a 1-year driving prohibition
• Second offence: 30 days imprisonment and a 2-year driving prohibition
• Third and subsequent: 120 days imprisonment and a 3-year driving prohibition
• Causing bodily harm: Maximum 14 years imprisonment
• Causing death: Maximum life imprisonment

Our Defence Strategy

1. Constitutional (Charter) Challenges

The majority of impaired driving cases involve interactions between police and motorists that engage fundamental constitutional rights. We investigate whether your Charter Rights were violated at any stage:

• Arbitrary Detention (Section 9): Did the police have a lawful reason to stop your vehicle? Random stops are permitted under R. v. Ladouceur, but investigative detentions beyond a simple traffic stop require reasonable suspicion.
• Unreasonable Search and Seizure (Section 8): Was the demand for a breath sample legally justified? The officer must have had a reasonable suspicion (for a roadside screening device) or reasonable and probable grounds (for the approved instrument at the station).
• Right to Counsel (Section 10(b)): Were you informed of your right to speak with a lawyer? Were you provided with a reasonable opportunity to do so in private? Was there any delay that violated your rights? Did the police properly facilitate access to duty counsel or a lawyer of your choice?

A successful Charter challenge can result in the exclusion of the breath results — which is often the entire case against you.

2. Technical Challenges to Breathalyzer Results

The machines used by police — the Intoxilyzer 8000C and the Draeger 9510 — are sophisticated instruments that must be maintained and operated according to strict standards. We scrutinize:

• Maintenance and calibration logs: Ensuring the device was properly calibrated, serviced on schedule, and not exhibiting any irregularities in the period surrounding your test.
• Operator qualifications: Verifying the qualified technician was properly trained and certified to operate the specific instrument used.
• Operational procedures: Checking whether the required 15-minute observation period was properly conducted (to ensure no mouth alcohol affected the result), whether the testing intervals were correct, and whether the two readings were within the acceptable range of each other.
• Bolus drinking defence: If you consumed a large amount of alcohol shortly before driving, your BAC may have been below 80 at the time of driving but rising during the time between the stop and the breath test. We analyze the timeline and, where appropriate, retain toxicology experts to establish that your BAC was below the legal limit at the time of operation.

3. Challenging the Observation of Impairment

For impairment charges (as opposed to Over 80), the Crown relies heavily on an officer’s observations of “signs of impairment” — bloodshot eyes, slurred speech, unsteadiness, odour of alcohol. We challenge these observations by:

• Providing alternative explanations: fatigue, medical conditions (diabetes, inner ear problems, anxiety), allergies, or environmental factors
• Using dashcam and body-worn camera footage — which is increasingly available — to contradict the officer’s written observations. It is common for video evidence to show a much more composed individual than the officer’s notes suggest.
• Challenging the officer’s training and experience in recognizing impairment versus nervousness, medical conditions, or physical limitations

4. The “Last Drink” Defence and Rising BAC

If you consumed alcohol shortly before driving, your body may not have fully absorbed the alcohol at the time you were behind the wheel. Your BAC could have been below 80 while driving but above 80 by the time you provided a sample at the station. This is known as the “rising BAC” or “bolus drinking” defence, and it requires careful analysis of the timeline and consultation with a toxicologist.

5. Negotiating to a Non-Criminal Outcome

Where the evidence presents challenges for the Crown but a trial carries risk, we negotiate aggressively. In appropriate cases, we have been successful in having criminal impaired driving charges reduced to non-criminal Highway Traffic Act offences, such as Careless Driving under Section 130 of the HTA. A careless driving conviction:

• Is not a criminal offence — no criminal record
• Results in demerit points and a possible fine
• Preserves your ability to travel to the United States
• Avoids the mandatory minimum penalties of a criminal conviction

This resolution is not available in every case, but where the circumstances allow, it can be the single most important outcome we achieve for our clients.

Immediate Steps to Protect Yourself

If you have been charged with impaired driving:

1. Write down everything you remember about the stop, the interaction with police, and the events leading up to it — while your memory is fresh.
2. Do not discuss the case with anyone other than your lawyer.
3. Contact us immediately — early involvement allows us to identify issues with the investigation before disclosure is even received.

Related Resources

• Your Charter Rights in a Criminal Case — deep dive on Sections 8, 9, and 10 arguments that win impaired driving cases
• What to Do If You’re Pulled Over for a DUI in Barrie — a quick-reference guide to your rights at roadside
• Drug Impaired Driving Defence — how drug impairment cases differ from alcohol cases
• Dangerous Driving Defence — sometimes charged alongside or as an alternative to impaired driving
• Fail to Remain — leaving the scene of an accident involving a motor vehicle
• First-Time Offender Guide — understanding your options if this is your first criminal charge
• Your First Court Appearance — what to expect the first time you go to court
• Early Interlock and Stream A — reducing your driving prohibition through early guilty plea and ignition interlock
• MTO Licence Consequences — administrative suspensions, escalating penalties, and reinstatement
• Mandatory Minimum Sentences — understanding the sentencing floor for impaired driving convictions

Charged with impaired driving? Contact us 24/7 for a confidential evaluation. Early legal advice can make all the difference.