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 Montana 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 Montana 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 have 20 minutes to correctly answer a minimum of 16 questions. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question 20

Passing Score 16

1. The ____ trailer is the most likely to turn over if a driver takes a turn too quickly.

Front

Last

Middle

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.

2. When braking with ABS, you should:

Push the brake pedal harder than usual.

Push the brake pedal as you normally would.

Push the brake pedal more lightly than usual.

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.

3. The emergency air line:

Is controlled by the foot brake.

Is connected to the relay valves.

Supplies air to the trailer air tanks.

Prevents skids.

The emergency air line (also known as the supply line) has two functions. The first is to supply air to the trailer air tanks on a combination vehicle, and the second is to control the emergency brakes.

4. When you are pulling a trailer, the air supply control lever should be in its ____ position.

Emergency

Supply

Normal

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.

5. A driver should test the tractor protection valve by:

Pulling the yellow, diamond-shaped knob.

Releasing air with the brake pedal.

Unlocking the trailer doors.

You should test the tractor protection valve by allowing the air supply to properly charge, turning off the engine, then releasing air from the system by pressing the brake pedal several times. The tractor protection valve should move into its emergency position when psi drops to an unsafe level.

6. If a trailer begins to jackknife, you should not:

Release the brakes.

Apply the trailer hand brake.

Allow the wheels to grip the road.

Allow the trailer to straighten out.

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 it will only prolong the skid. The application of brakes is what caused the wheels to lock in the first place.

7. The trailer hand valve should be used:

To test the trailer brakes.

To check the connection between the trailer and tractor.

To accelerate.

The trailer hand valve (also referred to as the "trolley valve" or "Johnson bar") works the trailer brakes and should be used only when testing them. Using the trailer hand valve while driving could result in a skid.

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