Instructions

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.. Read More

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 20

Passing Score 16

8. Large combination vehicles take the longest amount of time to stop:

When fully loaded.

When partially loaded.

When empty.

When mostly loaded.

Large combination vehicles take longer to stop when they are empty than when they are loaded. The decreased weight causes a vehicle's wheels to have decreased traction on the surface of the road.

9. During a trip, the ____ should be open.

Rear service line shut-off valve

Rear supply line shut-off valve

Inner shut-off valves

When starting a trip, be sure that all shut-off valves are in the open position, except for the last valves on the rear trailer. It is important that air reaches the brakes on all trailers and that it is not able to escape from the back of the vehicle.

10. The "crack-the-whip" effect can:

Turn over a trailer.

Be more effective than braking.

Make a truck move faster.

Trailers can overturn as a result of the "crack-the-whip" effect. The last trailer in a combination is the most prone to tip over due to this effect. Drivers should be aware of the rearward amplification of their specific vehicles and drive accordingly.

11. Look into the back of the fifth wheel:

While testing your air brakes.

If your vehicle begins to skid.

When inspecting a coupling.

While inspecting a coupling, you should go under the trailer and look into the back of the fifth wheel. Ensure that the fifth wheel jaws are secured around the shank of the kingpin.

12. How much space should be between the upper and lower fifth wheel?

About five inches of space

A maximum of two inches of space

No space

Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

13. Combination vehicles:

Often have taller trailers than single commercial vehicles.

Are usually lighter than single commercial vehicles.

Require more skill to drive than single commercial vehicles.

Driving combination vehicles requires more skill than driving single commercial vehicles. Combinations are generally longer, generally heavier, and are more vulnerable to rollover.

14. What does the tractor protection valve do?

Protects the tractor from being stolen

Protects the tractor from exceeding a set speed

Keeps air in the braking system, should the trailer break away or develop a leak

Ensures oil adequately lubricates the engine

The tractor protection valve keeps air in the tractor or truck braking system, should the trailer break away or develop a bad leak.

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