15. A driver should test the tractor protection valve by:
Pulling the yellow, diamond-shaped knob.
Releasing air with the brake pedal.
Unlocking the trailer doors.
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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 25 multiple-choice questions, and applicants will need to correctly answer a minimum of 20 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.
Number of Questions
25
Passing Score
20
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To Pass
0
Correct
0
Incorrect
0
18. If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can:
Look for a red light on the front right corner of the converter dolly.
Check for wheel speed sensors coming from the back of the brakes.
Pump the air brakes to activate the ABS.
Assume the vehicle has ABS.
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21. The trailer hand valve:
Should only be used for parking on a downhill.
Should only be used when transporting cargo.
Should always be used for parking.
Should never be used for parking.
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