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

1. An air supply control lever should be in its "normal" position when you are:

Changing a tire.

Applying the trailer emergency brakes.

Pulling a trailer.

Using your spring brakes.

Tractor protection controls in older vehicles may be operated by levers instead of knobs. If an air supply control is set in its "normal" position, it is properly set for you to pull a trailer.

2. Older trailers are not equipped with spring brakes. This means that if the air supply for a vehicle's air braking system leaks away:

The trailer will stop normally.

The trailer will not have brakes.

The trailer will speed up.

Older trailers do not have spring brakes. This means that if the air supply in an older trailer's air tank has leaked away, there will be no working brakes connected to the trailer and its wheels will turn freely.

3. In a double or triple combination:

Cargo weight must be evenly distributed between all trailers.

The heaviest trailer should be positioned directly behind the cab.

The heaviest trailer should be positioned in the rear.

The weight of the trailers does not matter.

When positioning trailers in a combination, the most heavily-loaded trailer should be the closest to the tractor. The lightest trailer should be positioned in the rear.

4. To prevent a rollover, cargo should be:

Placed near the front of a trailer.

Placed near the rear of a trailer.

Spread out on a trailer.

Loaded with most weight on the driver’s side of a trailer.

To reduce the risk of rollover, the weight of cargo in a trailer should be centered and spread out as much as possible. The weight of the cargo should also be kept as low to the ground as possible.

5. The trailer hand valve should:

Be used for parking.

Be used only to test the trailer brakes.

Be used together with the brake pedal.

Be used on slippery surfaces.

The trailer hand valve works the trailer brakes but should only be used when testing them. Using it while driving could create a skid. Never use the trailer hand valve while parking because doing so may release the air pressure from the braking system, releasing the brakes that are holding the vehicle in place.

6. Watching the road ahead:

Is more dangerous than only watching your mirrors.

Does not help you drive more safely.

Can help you avoid the need for sudden lane changes.

Making a sudden lane change can be dangerous while driving a combination vehicle. You can avoid the need to make a sudden lange change by looking down the road for upcoming obstacles that will require you to change lanes.