Two tests in one · Truck Knowledge (Class A/D) + Air Brake (Z Endorsement) · 80% to pass
Practice on the go and jump straight back to where you left off.
About the licence
An AZ licence (Class A plus the Z air-brake endorsement) covers full tractor-trailer combinations. A DZ licence (Class D plus Z) covers straight trucks over 11,000 kg. Both are issued by Ontario's Ministry of Transportation and require passing a vision test, a medical certificate, a written knowledge test, and a road test — Class A applicants also need mandatory entry-level training before their road test.
Because most commercial trucks are equipped with air brakes, almost every AZ/DZ applicant also needs the Air Brake (Z) Endorsement — a separate written knowledge test based on its own handbook, plus a hands-on practical test at a DriveTest centre.
Ontario doesn't publish one fixed question count for either written test the way it does for the G1 test. Driving schools and DriveTest test-prep resources consistently report roughly 40–60 questions at an 80% pass mark for the truck test and 20–25 questions for the air brake test. ExamHub's free practice quiz has 178 original questions across eight topic areas, written from the Official MTO Truck Handbook and the Official Air Brake Handbook.
What's covered
Try a few
Five questions pulled from the full bank, with the answer shown — use the quiz above for the real timed experience.
Why: A Class A licence is required once the towed vehicle exceeds 4,600 kg total gross weight. Class D covers a straight truck or combination up to that threshold; anything heavier requires Class A.
Why: Engage the parking brake, depress the clutch, and place the transmission in neutral before starting. On air-brake vehicles, verify pressure has built to a safe level and the warning buzzer/light is off before moving.
Why: Drivers are not permitted to drive with a major defect. Only minor defects are recorded on the report and reported to the operator; a major defect prohibits operation until it's repaired.
Why: The warning device must activate before pressure in either tank falls to 380 kPa (55 psi), though most devices activate at 414 kPa (60 psi) or higher.
Why: O. Reg. 555/06 requires a driver to have 10 hours off-duty in a day. This daily requirement is distinct from the separate 36- or 72-hour resets used between cycles.
FAQ
Because Ontario requires two separate knowledge tests for most AZ/DZ drivers: the Class A or D truck test (based on the Official MTO Truck Handbook) and the Air Brake (Z) Endorsement test (based on the Official Air Brake Handbook), since most commercial trucks have air brakes. Test Me and Practice both let you pick Truck Knowledge or Air Brake separately.
The letters describe your base licence class plus the air brake (Z) endorsement. A Class A licence covers full tractor-trailer combinations where the towed vehicle exceeds 4,600 kg; Class D covers straight trucks over 11,000 kg gross weight. Both require the Z endorsement if the vehicle has air brakes, which most commercial trucks do.
Licence classes and requirements, CVOR, vehicle size and weight limits, daily trip inspections, hours-of-service rules, starting/braking/parking/stopping procedures, turns, backing, coupling and uncoupling (Class A), safe and responsible driving, and truck-specific signs — all from the Official MTO Truck Handbook.
No — the mandatory entry-level training course applies only to new Class A applicants, before their Class A road test. Class D applicants don't need it.
If you pass your Class A road test in a vehicle that doesn't meet full Class A requirements — for example, a trailer without air brakes — you're issued an AR (A Restricted) licence instead, which can't pull a full tractor-trailer or an air-braked trailer.
The air supply subsystem (compressor, governor, tanks, safety valve), service, spring, and trailer brake subsystems, foundation brakes, and the exact inspection procedures — the low air-pressure warning test, air pressure build-up time, governor settings, and air-loss rate — all from the Official Air Brake Handbook.
Yes, if the truck has air brakes — and most large commercial vehicles in Ontario do. The Z endorsement is a separate knowledge test and practical test on top of your base Class D licence.
No. This quiz covers the written knowledge tests only. The air brake endorsement also requires a separate hands-on practical test at a DriveTest centre (there are two versions depending on your vehicle's configuration), which isn't something a multiple-choice quiz can prepare you for. Since September 2023, renewing an existing Z endorsement uses an online learning module instead of the knowledge test, but new applicants still need to pass it.
Ontario's MTO doesn't publish a single fixed count the way it does for G1. Driving schools and DriveTest test-prep resources consistently report roughly 40–60 multiple-choice questions at an 80% pass mark for the Class A/D truck test, and 20–25 questions for the separate Air Brake (Z) Endorsement test.
No. These are original questions written by ExamHub from the Official MTO Truck Handbook and Official Air Brake Handbook. They cover the same material but aren't copies of any provider's exam or any other practice site.
Also preparing for another exam? Try our , and Ontario G1 free practice test.