Ontario Commercial Licence Practice 2026 · Class A, B/C & D

Ontario's commercial knowledge test covers the rules and operating standards for class a / az (tractor-trailer with air brakes). It's administered by Ministry of Transportation Ontario (MTO). The MTO does not publish a pass mark or the number of questions for this test. No time limit is published. Class A covers any tractor-trailer combination, and the Z endorsement is required to drive any air-brake-equipped motor vehicle. Ontario's other commercial classes are B (school-purposes bus), C (regular bus), D (trucks over 11,000 kg), E (school-purposes bus up to 24 passengers) and F (regular bus up to 24 passengers, and ambulances).

Hours of service are a major topic on the test. The federal rules apply to carriers that operate across provincial borders, and once a carrier falls under them, all of its drivers must comply, even those who never leave the province. In a day you cannot drive after 13 hours of driving or 14 hours on duty, and in a work shift you cannot drive once 16 hours have passed since your last 8 consecutive hours off duty. Cycle 1 allows 70 hours on duty in 7 days and Cycle 2 allows 120 hours in 14 days; 36 consecutive hours off resets Cycle 1 and 72 resets Cycle 2. Carriers must equip their vehicles with a certified electronic logging device (ELD) unless an exemption applies, such as local driving.

Air-brake systems are fundamental to most heavy commercial vehicles and operate on a different principle than hydraulic brakes - air pressure releases spring-loaded brakes rather than applying them. Loss of air pressure causes spring-brake application, which is why the system "fails safe." The test covers air-brake fundamentals: governor cut-out and cut-in pressure (cut-out is typically 120 to 135 psi, with cut-in 20 to 25 psi lower), the low-air warning (it must come on before pressure drops below 60 psi, or 414 kPa), the 20 to 45 psi range where spring brakes apply, and slack adjuster inspection.

Pre-trip inspection is one of the most important duties of a commercial driver and is heavily tested. A complete pre-trip covers: tires (tread depth, sidewall damage), wheels (lug nut visual check), brakes (slack, drum/rotor inspection, hose integrity), lights, mirrors, fluids, fifth wheel, kingpin, and trailer connections.

Cargo securement follows National Safety Code (NSC) Standard 10, which sets minimum tie-down requirements based on cargo weight, type, and trailer configuration. Transporting dangerous goods falls under the Transportation of Dangerous Goods (TDG) rules, which are the same across Canada: drivers carry the shipping documents, display the proper placards, and hold a TDG Certificate of Training issued by their employer, valid for 36 months. It is a training certificate, not a licence endorsement.

Brushing up on Canadian road signs? Our sign-specific practice covers every regulatory, warning, and information sign you'll see on the test.