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. Applicants should answer at a rate of about one question per minute. The Combination test is not a replacement for the Double/Triple endorsement test.
Number of Question
Passing Score
8. When testing ____, you should apply your vehicle's brakes with the hand control while moving the vehicle forward slowly.
Explanation
To test the trailer service brakes, you should first ensure that the braking system has a normal air pressure level, then release the parking brake. You should then move the vehicle forward slowly and apply the brakes with the hand control. If the trailer service brakes are working properly, you will feel the brakes activate.
9. Rollovers happen when:
Explanation
Rollovers are caused by operators turning too fast. To avoid rolling over, drive slowly on entrance ramps, on exit ramps, and around corners. Avoid making quick lane changes when towing trailers.
10. What does an Anti-Lock Braking System (ABS) do?
Explanation
An Anti-Lock Braking System (ABS) helps prevent wheel lockup during hard braking. If ABS detects impending lockup, it reduces braking pressure to a safe level.
11. If you use the trailer hand brake while your trailer is skidding, it 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.
12. 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.
13. If a trailer begins to jackknife, the driver:
Explanation
If a trailer begins to jackknife, you should release the brakes and allow the trailer wheels to regain traction with the road. Do not apply the trailer hand brake to attempt to straighten out the rig because the application of brakes is what caused the wheels to lock in the first place.
14. If you must cross traffic while driving a combination vehicle, you should:
Explanation
