Combination
All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Commercial Driver License Manual. Section 6 provides the information needed to safely operate tractor-trailers, doubles, triples, and straight trucks with trailers. The test is made up of 20 multiple-choice questions, and applicants will need to correctly answer a minimum of 16 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.
Number of Question
Passing Score
1. What is another name for the service line?
Explanation
The trailer service air line is also referred to as the control line or signal line.
2. When driving a tractor-trailer equipped with ABS, you should:
Explanation
When driving a tractor-trailer combination equipped with an Anti-Lock Braking System (ABS), you should brake in the same manner that you would in a vehicle without ABS.
3. While inspecting a coupling, you should go under the trailer and:
Explanation
While inspecting a coupling, you should go under the trailer and look into the back of the fifth wheel. Ensure that the fifth wheel jaws are secured around the shank of the kingpin.
4. Rollovers happen when:
Explanation
Rollovers happen when a vehicle is driven too fast. To reduce the risk of rollover, make sure the weight of cargo is loaded low to the ground, and that you take turns and curves slowly.
5. Using the trailer hand brake while experiencing a trailer jackknife will:
Explanation
If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.
6. Emergency air lines are often coded with the color:
Explanation
In general, the parts of the service air line are coded blue and the parts of the emergency air line are coded red.
7. If oil and water build up in your vehicle's air tanks, the brakes:
Explanation
