Driving while impaired by drugs is treated as seriously as driving drunk. Alberta’s Immediate Roadside Sanctions apply to impairment by alcohol, drugs, prescription drugs or a combination of them. Federal Criminal Code limits also apply.
How Alberta handles drug impairment
- IRS 24-hour: if police suspect you are impaired by drugs, they can suspend your licence for 24 hours.
- IRS WARN: also applies if you fail drug and alcohol sobriety tests.
- IRS FAIL: applies if you fail or refuse drug and alcohol testing or fail a drug recognition evaluation. It carries a 90-day suspension, a 30-day vehicle seizure and a $1,000 fine on a first occurrence. See Alberta DUI penalties.
Cannabis: federal THC limits
The Criminal Code sets blood drug concentration limits for THC, the main impairing compound in cannabis:
- 2 ng to under 5 ng of THC per mL of blood: a less serious offence, punishable by a fine of up to $1,000.
- 5 ng or more: a criminal impaired driving offence with the same mandatory minimum penalties as alcohol.
- Alcohol and cannabis combined: 50 mg of alcohol per 100 mL of blood plus 2.5 ng or more of THC.
Prescription and over-the-counter medication
Legal medication can still impair your driving. If it does, you can face the same IRS penalties and criminal charges as for any other drug. Read the warning labels and ask your pharmacist or doctor whether it is safe to drive.
New drivers
Learner and GDL drivers must have no drugs at all in their system — see Alberta GDL zero-tolerance rules. For the full system, see our Alberta impaired driving laws guide.
Frequently asked questions
Under the Criminal Code, having 2 ng to under 5 ng of THC per mL of blood is a less serious offence with a fine of up to $1,000; 5 ng or more is a criminal impaired driving offence.
Yes. Alberta's impaired driving penalties apply to impairment from prescription drugs as well as alcohol and illegal drugs.
Failing drug recognition tests falls under IRS FAIL: a 90-day suspension, then a longer suspension with an interlock option, a 30-day vehicle seizure and a $1,000 fine on a first occurrence.
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This article is general information about Alberta and Canadian impaired driving law as of October 2026. It is not legal advice. Penalties and procedures can change; speak with a lawyer about your situation.
Sources: Government of Alberta, Impaired driving penalties; Government of Alberta, IRS FAIL Ignition Interlock Program; Department of Justice Canada, Impaired driving laws.
