The practical rule: do not drive after cannabis
B.C. says cannabis impairment is subjective, can differ between people and may not align with THC levels. A person may feel unimpaired and still be under the influence. The province says there is no standard or safe time to wait before driving; this is why a simple hour-count is not a clearance test.
B.C. roadside thresholds are not a safety test
B.C.'s guidance lists federal criminal thresholds separately from the provincial Administrative Driving Prohibition (ADP). A blood sample with more than 2 ng/mL THC can trigger a federal impaired-driving charge; penalties become more serious above 5 ng/mL, or above 2.5 ng/mL with alcohol. Separately, B.C.'s guidance lists an immediate 90-day ADP suspension when a sample taken within two hours of driving contains more than 5 ng/mL THC, or 2.5 ng/mL THC with alcohol. These are legal triggers, not safety limits; impairment remains unlawful at any level. Police may use roadside procedures, so do not self-clear using a number. See the province's current driving guidance.
New drivers and vehicle transport
B.C.'s Graduated Licensing Program prohibits any THC in a new driver's system. The province describes an immediate 12-hour suspension and possible further effects on the licensing period. Passengers may not consume cannabis in a vehicle. For possession/packaging amounts, see B.C. possession limits.
Quick FAQ
Is there a standard number of hours to wait before driving?
No. B.C. says cannabis affects people differently and there is no standard or safe time to wait before driving.
Do blood-THC thresholds tell me I am safe to drive?
No. More than 2 ng/mL of THC can trigger a federal impaired-driving charge; penalties become more serious above 5 ng/mL, or above 2.5 ng/mL with alcohol. Separately, B.C.'s guidance lists an immediate 90-day administrative suspension above 5 ng/mL, or at 2.5 ng/mL with alcohol, within two hours of driving. These are legal thresholds, not safety targets.
Do novice drivers have different rules?
Yes. B.C. says its Graduated Licensing Program has zero tolerance for THC; any presence may lead to an immediate 12-hour suspension and other consequences.
Sources
- B.C. Government: Cannabis and driving -- directly read 2026-09-25; page last updated May 20, 2026.
- RoadSafetyBC: Alcohol and drug related driving prohibitions -- directly read 2026-09-25.
Sources checked 2026-09-25.