Impaired Driving Charges: What You Need to Know

Impaired driving offences carry some of the most severe consequences in Canadian criminal law, including lengthy driving prohibitions and far-reaching collateral consequences. The legal landscape has also changed dramatically with Bill C-46 (2018), which introduced new offences and expanded police powers.

The Current Legal Framework

Impaired driving offences are found in Sections 320.14 to 320.19 of the Criminal Code. The main offences are:

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

Operating a conveyance (vehicle, vessel, aircraft, or railway equipment) while your ability to operate is impaired to any degree by alcohol, drugs, or a combination. "Impaired to any degree" is a low threshold—the Crown does not need to prove you were "drunk," only that your ability to operate was affected.

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

Operating a conveyance with a blood alcohol concentration (BAC) equal to or exceeding 80 mg of alcohol per 100 ml of blood within two hours of ceasing to operate. Note the critical change: under the old law, your BAC had to be over 80 at the time of driving. Now, it is an offence to be over 80 within two hours of driving, regardless of when you consumed alcohol.

Drug-Impaired Driving (Section 320.14(1)(c) and (d))

Operating with blood drug concentrations exceeding prescribed limits. For THC (cannabis), the limits are 2 to 5 nanograms per ml of blood for a summary conviction offence, 5 nanograms or more for a hybrid offence with higher penalties, and a combined limit of 50 mg alcohol plus 2.5 nanograms THC.

Refusal or Failure to Comply (Section 320.15)

Failing or refusing to comply with a demand for breath samples, blood samples, or physical coordination tests. This offence carries the same penalties as impaired driving—there is no advantage to refusing.

Impaired Operation Causing Bodily Harm or Death

These are among the most serious offences in the Criminal Code under Sections 320.14(2) and (3). Impaired driving causing death can result in life imprisonment.

Approved Screening Devices and Evidentiary Breath Tests

Police can demand a breath sample using an Approved Screening Device (ASD) at the roadside if they have reasonable suspicion you have alcohol in your body. Under Bill C-46, police can now demand an ASD sample from any driver they lawfully stop, even without suspicion—though this "mandatory alcohol screening" provision is being challenged in courts.

If you fail or register a "warn" on the ASD, police will demand you accompany them to provide evidentiary breath samples on an Approved Instrument at the station. Two samples are taken, at least 15 minutes apart, and the lower reading is used as evidence.

Drug Recognition Evaluations

For suspected drug impairment, police may demand Standardized Field Sobriety Tests (SFST) at the roadside, evaluation by a Drug Recognition Expert (DRE) at the station, and blood or urine samples for laboratory analysis. DRE evaluations are complex 12-step assessments that trained officers use to identify drug categories causing impairment. Their reliability is frequently challenged in court.

Defences to Impaired Driving Charges

Every case is unique, but common defence strategies include:

Charter Violations

Was there a lawful basis for the initial stop? Was the ASD demand made with reasonable suspicion (for pre-C-46 cases)? Were you informed of your right to counsel? Were you given a reasonable opportunity to contact a lawyer? Were delays in the breath testing process unreasonable? If Charter rights are violated, evidence may be excluded under Section 24(2), potentially resulting in acquittal.

Challenging the Breath Test Results

Was the Approved Instrument properly maintained and calibrated? Was the operator qualified and did they follow proper procedures? Can you raise a reasonable doubt about the accuracy of the readings? Did you consume alcohol after driving but before testing (the "bolus drinking" defence)?

Challenging Impairment Evidence

Are the observations of impairment consistent with the alleged BAC? Could physical symptoms be explained by other factors (fatigue, medical conditions, nervousness)? Was the driving actually erratic, or is there another explanation?

Identity and Care or Control

Can the Crown prove you were the driver? If charged with "care or control" while parked, can you establish you had no intention to drive?

Collateral Consequences Beyond the Criminal Case

An impaired driving conviction affects far more than your criminal record.

Driving Prohibitions and Ignition Interlock

Federal driving prohibitions run from 1 year to life. Provincial administrative penalties often add further suspensions. To regain your license, most provinces require participation in an ignition interlock program (a device that requires a breath sample before the vehicle will start) for at least one year.

Insurance Consequences

Your insurance rates will increase dramatically—often 3 to 5 times higher—for years after a conviction. Some insurers will refuse to cover you entirely, requiring you to obtain high-risk insurance.

Travel Restrictions

The United States treats impaired driving as a serious offence. A conviction can render you inadmissible to the US, requiring a formal waiver application to enter. This process is expensive, time-consuming, and not guaranteed.

Employment Consequences

A criminal record can affect employment, particularly in fields requiring driving or security clearances. Professional licensing bodies (for lawyers, doctors, nurses, teachers, etc.) must be notified of criminal convictions.

Why Early Legal Intervention Is Critical

Impaired driving cases are document-intensive. Your lawyer needs to obtain disclosure promptly, including the Certificate of Analysis, Approved Instrument maintenance and calibration records, officer training records, video footage (if available), and communications logs. Some evidence (like dispatch recordings) may be destroyed after a limited time. Engaging counsel immediately ensures that all relevant evidence is preserved for your defence.