Based on 2023 ON commercial driver's license manual Instant feedback
The Ontario DZ written test is split into two parts: the Class D license knowledge test, and the Z endorsement test for air brakes. The knowledge test for Class D contains 40 multiple-choice questions about large trucks, and combination vehicles along with trucking regulations. There are two sections: 20 questions focused on road rules specific to heavy trucks and commercial vehicles, and 20 questions on associated road signs and trucking signals. The Z endorsement test, which is separate, tests knowledge of air brakes, how they operate, and how to inspect them. Thus, to acquire a DZ license, both the D license test and Z endorsement test must be passed. If you don't pass either test, you can retake the failed one after repaying the associated fees. Looking for a free Ontario DZ practice test? Take this test below for the D license part, and this free Air Brake practice test for your Z endorsement.
In determining how well your air brake system works, which is NOT a significant factor?
Which colour is the trailer supply line?
When is a pre-trip inspection required?
What gauges should you check after starting your vehicle?
Why are there two service tanks in a modern air brake system?
What is the purpose of the National Safety Code?
What does this sign mean?
In Canada, how many classes of dangerous goods are there?
What must you do at a stop sign with a painted stop line?
When brakes become overheated, they also become
What does this sign mean?
Your vehicle is equipped with an air brake system, including a belt-driven air compressor. How do you check for correct belt tension?
What does this sign mean?
Before driving down a grade (hill), you should
What does this sign mean?
Your vehicle has tandem drive axles and is equipped with an inter-axle differential. You should NOT use it if
What does this sign mean?
What is a commercial vehicle's danger zone?
This sign indicates that you may park for one hour
What is the first step of the pre-trip inspection?
In a vehicle equipped with air brakes, the pushrod stroke occurs when compressed air enters the
What is the Gross Vehicle Weight Rating (GVWR)?
Driving a commercial vehicle on the road is
In an air brake system, what does a governor do?
Where are the air brake chambers located?
Pass Guarantee
How does it work?
Our Premium Membership comes with a Pass Guarantee (30-day access and longer). If you successfully complete all the practice tests for your province/territory, we promise you a passing grade on your official written knowledge test or we'll refund your money. Your most recent completion of all the tests should be not earlier than 30 days before your exam date.
To claim
Just send us an email with your full name (must match the name and email address used for your purchase at Tests.ca) within 30 days from the purchase of your Premium membership.
What happens next
We'll check your account to make sure you've successfully completed all practice tests for your state. Once that is confirmed, we'll issue a full refund (you'll receive a separate email confirmation).
Know your exam date? Select it here:
If you know the date of your official knowledge exam, select it here: