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 Oregon Commercial Driver.. 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 Oregon Commercial Driver 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. The trailer hand valve should be used:

Regularly to activate the trailer brakes in all driving conditions.

Only to test the trailer brakes.

Only in inclement weather when the trailer may skid.

Only if the trailer is carrying a load.

The trailer hand valve should be used only to test the trailer brakes. It should not be used while driving because it may cause the trailer to skid.

9. If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can:

Check for wheel speed sensors coming from the back of the brakes.

Look for a red light on the front right corner of the converter dolly.

Pump the air brakes to activate the ABS.

Assume the vehicle has ABS.

If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can check under the trailer for wheel speed sensors coming from the back of the brakes.

10. When a vehicle goes around a corner, the rear wheels:

Follow the same path as the front wheels.

Follow a different path than the front wheels.

Should not be a concern to the driver.

When any vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking. The degree of off-tracking will be greater on long vehicles than on short vehicles.

11. To find out if a vehicle that was built before 1998 has an Anti-Lock Braking System (ABS), you can:

Pump the air brakes to activate the ABS.

Look into the back of the fifth wheel.

Check for wheel speed sensors coming from the back of the brakes.

12. If a load is placed on one side of a trailer, the trailer:

May lean, and could result in a rollover.

May add extra support during turns.

Have improved braking.

Have improved steering.

If the weight of a load is placed primarily one side of a trailer, the trailer may lean, increasing the risk of a rollover.

13. What can the “crack-the-whip” effect do?

Turn over trailers.

Make loud noises.

Make trucks accelerate.

Make trucks decelerate.

The "crack-the-whip" effect can cause a trailer to turn over during a lane change. To avoid this phenomenon, drivers should make lane changes at slow, safe speeds.

14. When connecting a converter dolly to a second trailer, the trailer height should be ____ the center of the fifth wheel.

Level with

Slightly higher than

Slightly lower than

When connecting a converter dolly to a second or third trailer, the trailer height should correct. It should be slightly lower than the center of the fifth wheel.

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