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 have one hour to correctly answer a minimum of 16 questions. The Combination test is not a replacement for the Double/Triple endorsement test.
Number of Question
Passing Score
15. In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when:
Explanation
In vehicles equipped with an automatic tractor protection valve, the valve will pop out if air pressure drops to a level between 20 and 45 psi. When the valve pops out, the protection valve will close, stopping the flow of air.
16. The ____ trailer is the most likely to turn over if a driver takes a turn too quickly.
Explanation
When making a turn, be sure to steer gently and smoothly. Making a quick turn while pulling trailers is dangerous and can increase the risk of the last trailer rolling over.
17. After coupling, there should be ____ between the upper and lower fifth wheel.
Explanation
Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.
18. Fully-loaded rigs:
Explanation
Because the weight of cargo gives them a higher center of gravity, fully-loaded rigs are 10 times more likely to roll over in a crash than empty rigs.
19. 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.
20. To lower the risk of a rollover, you should:
Explanation
