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.
15. Before a drive, ensure that air flows to all trailers by:
Before a trip, ensure that air in the air brake system reaches all trailers. Do this by waiting for air pressure to build, then sending air to both the emergency and service lines and opening the shut-off valves on the rear of the last trailer. If air escapes from the shut-off valves in the rear of the combination, the air is being supplied to the entire vehicle.
16. Look for matching colors when coupling glad hands. Service lines are often:
When coupling glad hands, make sure to couple together matching glad hands. To help drivers avoid mistakes, color coding is sometimes used. Service lines are often coded with the color blue and emergency lines are often coded with the color red.
17. A loss of air pressure in the emergency line will cause:
The emergency air line controls the emergency brakes on a combination vehicle. A loss of air pressure in the emergency line will cause the emergency trailer brakes to activate.
18. When braking with ABS, you should:
When operating a vehicle with an Anti-Lock Braking System (ABS), you should apply your brakes in the same manner as you would if operating a vehicle without ABS.
19. How much space should be between the upper and lower fifth wheel?
Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.
20. If the trailer begins to skid, it is best to:
If your trailer begins to skid, you should release the brakes to help regain traction. Once the wheels grip the road again, the trailer will begin to straighten out and follow the path of the tractor.
See the exact questions that will be on the 2025 South Dakota DMV exam.
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Alexa shares with us how she went in for her Class A permit and decided to get her Hazmat endorsement as a bonus!
Mark shares his feedback on his Class A CDL Cheat Sheet
