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DZ Practice Test Ontario 2026 – Free Ontario Class D (DZ) Questions

Original questions written from the official Ontario handbook, with an explanation for every answer.

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  • 272 questions
  • 7 practice tests
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Practice test 1 · Question 1Score 0/0

On some trucks, what may you need to do while releasing the clutch to move off?

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All Ontario Class D (DZ) practice tests

7 sets of 40 questions. Each set is fixed, so you can repeat it until you score 100%.

Exam facts

Key facts: Ontario Class D (DZ) Truck Knowledge Test

Free Ontario DZ practice tests for the Class D heavy truck knowledge test, written from the Official MTO Truck Handbook. Every question is original, explains the rule behind the answer and names the handbook page it comes from. No sign-up and no paywall; your progress stays on your device.

Class D is the licence for straight trucks over 11,000 kg: dump trucks, tandem-axle flatbeds, large cube vans and service trucks. This bank is built around that work: what Class D does and does not cover, straight-truck inspections and brake checks, the inter-axle differential lock, off-tracking and backing a long wheelbase, Class D renewals and medicals, plus the shared rules every truck driver is tested on.

What the test covers

Topics and question bank

Every question is tagged to one topic from the official handbook. Pick a topic to drill just that area.

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Sample Ontario Class D (DZ) questions

Tap a question to see the answer. The full interactive test is at the top of the page.
  1. 1On some trucks, what may you need to do while releasing the clutch to move off?
    • A. Add a little throttle
    • B. Turn off the engine brake switch
    • C. Press the service brake hard
    • D. Shift back into neutral

    When starting to move, release the clutch gradually while releasing the parking brake; on some vehicles the engine must be speeded up gradually to prevent stalling.

  2. 2Who can receive the fine if a truck illegally passes a school bus and the driver is not charged?
    • A. The registered owner
    • B. No one at all
    • C. The school bus driver
    • D. The shipper of the load

    As the vehicle's registered owner, you may receive the fines if the driver is not charged; unpaid fines block permit renewal.

  3. 3You come to an intersection with no signs or lights. Who has the right-of-way?
    • A. The vehicle on your right
    • B. The heavier of the two vehicles
    • C. The faster of the two vehicles
    • D. The vehicle coming from your left

    At an intersection without signs or lights, yield the right-of-way to any vehicle approaching from the right.

  4. 4What does a solid line on the left side of your lane mean?
    • A. Parking is allowed
    • B. A bike lane is beside you
    • C. You may pass freely
    • D. It is unsafe to pass

    A solid line at the left of your lane means passing is unsafe; a broken line means you may pass when the way is clear.

  5. 5Your truck stalls on a busy road. What is your first priority if it can still move?
    • A. Leave it and call a tow truck at once
    • B. Set flares in your lane before anything
    • C. Get it off the road if you can
    • D. Wait inside with the doors locked

    If the vehicle can be moved, move it as far off the roadway as safely possible, then turn on the hazard flashers.

  6. 6A truck is caught a second time within two years with critical defects. How long is the impoundment?
    • A. 15 days
    • B. 30 days
    • C. 60 days
    • D. 45 days

    The impound period doubles to 30 days for a second offence within two years, and rises to 60 days for a third.

  7. 7The light turns yellow as you approach. What should you do?
    • A. Speed up to clear it
    • B. Always stop instantly
    • C. Sound the horn and go
    • D. Stop if you can do so safely

    A yellow light means the red is about to appear; stop if you can do so safely, otherwise go with caution.

  8. 8When is pumping (fanning) the brakes useful?
    • A. On dry pavement
    • B. When parked on a hill
    • C. On long downgrades
    • D. On slippery pavement

    Fanning the brakes gives better control and a shorter stop only on slippery pavement; on dry pavement it just wastes air.

  9. 9Your tandem dump truck approaches a muddy site entrance. When should you lock the differential?
    • A. Before reaching the slippery area
    • B. After the wheels start spinning
    • C. Only at highway speed
    • D. Never on a work site

    Use the lock position when you approach conditions where wheels may slip, and never engage it while wheels are actually spinning.

  10. 10For a tight right turn, which lane of the street you are entering might you need to use?
    • A. The bike lane
    • B. Only the curb lane
    • C. The second lane
    • D. The opposite sidewalk

    Depending on the vehicle and lane widths, you may need to cross the centre line or use the second lane of the street entered.

About the test

About the Ontario Class D (DZ) Truck Knowledge Test

A Class D licence lets you drive a motor vehicle over 11,000 kg gross or registered gross weight, including a truck towing a trailer of up to 4,600 kg, and any vehicle covered by Class G. It does not cover buses carrying passengers, motorcycles or mopeds, and a trailer over 4,600 kg needs a full or restricted Class A. Most DZ trucks have air brakes, so drivers usually add the Z air brake endorsement, which is why the licence is often called DZ.

To apply you must be at least 18, hold a valid Ontario Class G or higher licence, pass a vision test, submit a satisfactory medical report and pass the knowledge test on operating large trucks. The road test is taken in a vehicle that meets Class D requirements. Unlike Class A, Class D has no mandatory entry-level training. A separate Class D with RV restriction (condition Q) covers heavy recreational vehicles only and uses a learning module instead.

Ontario does not publish the number of questions on the Class D knowledge test. DriveTest says all its knowledge tests are multiple choice, not timed, marked on the spot and available in English and French (commercial tests also in 18 other languages on computer), and that you need a total score of at least 80 percent. Our mock exam uses 40 questions and a pass mark of 32 (80 percent) as a practice standard, not as the official format.

The knowledge test is written from the Official MTO Truck Handbook, which covers both Class A and Class D. Shared topics include daily inspections, hours of service, cargo securement, weights and CVOR, sharing the road and signs. This DZ bank weights the material differently from our AZ bank and asks different questions: it leaves out coupling and tractor-trailer braking and adds straight-truck brake checks, transmission and differential-lock use, Class D licence and RV rules, Class D renewal and medical rules, and fuel-efficient driving.

Since July 1, 2018, Class D drivers also renew with a vision and knowledge test and must file periodic medical reports, so the same handbook matters again at every renewal.

Study plan

How to prepare

  1. 1Read the Official MTO Truck Handbook once. It is free on ontario.ca and every question here cites a page of it.
  2. 2Be sure you can say exactly what Class D covers: over 11,000 kg, towing up to 4,600 kg, plus Class G; not buses with passengers, and not trailers over 4,600 kg.
  3. 3Learn the straight-truck brake numbers: air loss no more than 3 psi in a minute, build-up from 85 to 100 psi within two minutes, low-air warning at or above 55 psi, spring brakes applying around 60 psi.
  4. 4Learn the hydraulic brake checks: pump out the power assist, apply, start the engine and watch the pedal; a steady drop means out of service.
  5. 5Memorize the hours-of-service limits and the cargo re-check triggers (80 km, then 3 hours, 240 km or a duty change).
  6. 6Take one practice test per topic, then reread the handbook page cited under each question you miss.
  7. 7When you score 36 or more out of 40 on two different mock exams in a row, you are ready to book the knowledge test.
  8. 8Bring two pieces of ID, your completed medical report, the test fee and any glasses you need to read.

FAQ

Ontario Class D (DZ) test questions people ask

How many questions are on the Ontario DZ written test?

Ontario and DriveTest do not publish the number of questions on the Class D knowledge test. Our mock exam uses 40 questions as a practice standard; treat that number as ours, not the official format.

What is the pass mark for the DZ knowledge test?

DriveTest states that its knowledge tests need a total score of at least 80 percent and are not timed. Our mock asks for 32 out of 40, which is 80 percent.

How much does the Class D knowledge test cost?

DriveTest's fee list shows $23.75 for a commercial knowledge test and $122.75 for the commercial licence package (knowledge test plus road test) for applicants under 65. Confirm current fees on drivetest.ca.

What is the difference between D and DZ?

Class D is the licence class for heavy straight trucks. The Z is the air brake endorsement added on top, needed to drive any truck with air brakes or air-over-hydraulic brakes. It has its own knowledge and practical test; use our Ontario air brake (Z) practice test for it.

Do I need mandatory training for a Class D licence?

No. Mandatory entry-level training applies to Class A. For Class D you need to be 18, hold a full G, pass the vision and knowledge tests, file a medical report and pass the road test.

Can I drive a big RV with a Class D?

Yes. A full Class D covers any recreational vehicle. If you only want to drive a heavy RV, a Class D with RV restriction is available, and since July 1, 2025 a G licence covers RVs up to 11,000 kg (14,000 kg with an RV endorsement).

Is the DZ test the same as the AZ test?

Both come from the same truck handbook, but Class A adds tractor-trailer topics like coupling and combination braking. We keep separate banks: this one focuses on straight trucks and has different questions from our AZ practice test.

Are these the real DZ test questions?

No. Real test questions are not public. Every question here is written by us from the Official MTO Truck Handbook and cites the page it comes from.

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