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. Rollovers are most likely to happen when:
Explanation
Rollovers happen when an operator turns too fast. Drivers should be sure to slow down before entering turns and curves, especially when transporting a fully-loaded rig.
2. All trailers made after ____ must be equipped with Anti-Lock Braking Systems (ABS).
Explanation
All trailers and converter dollies manufactured on or after March 1, 1998 must have Anti-Lock Braking Systems (ABS).
3. Push in the trailer air supply control to:
Explanation
Push in the trailer air supply control to supply the trailer with air. Pull out the trailer air supply control to turn off the air supply and activate the emergency brakes.
4. Pull out the trailer air supply control to test:
Explanation
Be sure to test the trailer emergency brakes before beginning a trip. After ensuring that the trailer rolls freely, you can test the emergency brakes by pulling out the trailer air supply control, or placing it in the "emergency" position. Pull forward slightly with the tractor and make sure the trailer does not move.
5. What is another name for the service line?
Explanation
The trailer service air line may also be referred to as the control line or signal line.
6. Which of the following types of vehicles is most prone to the “crack-the-whip" effect?
Explanation
Double and triple combinations are the most vulnerable to turning over as a result of the "crack-the-whip" effect.
7. A trailer that is too high:
Explanation
