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 30 multiple-choice questions, and applicants will need to correctly answer a minimum of 24 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question 30

Passing Score 25

1. The best way to notice if a trailer has begun to skid is to:

Ask another driver.

Use your mirrors to determine if the trailer has left the lane.

Look at the skid sensor.

Feel the tractor move.

The easiest way to become aware that your trailer has begun to skid is to observe it in your mirrors. Checking your trailer in your mirrors will also allow you to spot any skidding at the earliest possible moment.

2. A loss of air pressure in the emergency line will cause:

The service brakes to activate.

The tractor protection valve to close.

The rear trailer to detach from the combination.

The suspension springs to extend.

The tractor protection valve keeps air in the trailer's braking system should the trailer break away or develop a leak. A loss of air pressure in the emergency line will cause the tractor protection valve to open and the emergency trailer brakes to activate.

3. Place the trailer air supply control in its "emergency" position to test:

The trailer emergency brakes.

A coupling device.

The anti-lock brakes.

Be sure to test the trailer emergency brakes before beginning a trip. After ensuring that the trailer rolls freely, you can test the emergency brakes by pulling out the trailer air supply control, or placing it in the "emergency" position. Pull forward slightly with the tractor and make sure the trailer does not move.

4. What is a bobtail tractor?

A tractor without a trailer

A tractor attached to two trailers

A tractor with a tank

Tractors without semi-trailers are referred to as bobtail tractors. Operating a bobtail tractor requires drivers to exercise caution.

5. A tractor protection valve is:

A device that keeps air in the tractor or truck brake system, should the trailer break away or develop a bad leak.

A device that prevents theft.

A device that controls fuel levels.

A device that allows the battery to recharge efficiently.

On combination vehicles with air brakes, the tractor protection valve keeps air in the tractor or truck brake system, should the trailer develop a bad leak or break away from the tractor.

6. Proper coupling technique:

Is the same on all vehicles.

Is essential to the safe operation of a vehicle.

Includes ensuring that the fifth wheel plate is not greased.

Can be learned over time.

Knowing proper coupling and uncoupling technique is fundamental to the safe operation of combination vehicles. Improper coupling can be very dangerous.

7. In an empty combination vehicle, the stiff suspension springs and strong brakes will have:

High traction.

Low traction.

No traction.

An empty combination vehicle will come to a complete stop more slowly than a fully-loaded vehicle. With less weight in a trailer, the stiff suspension springs and strong brakes will have lower traction than they would if the vehicle carried more weight.

8. Rollovers happen when:

A truck driver is driving too fast.

The driver of a vehicle in front of a truck is moving to slowly.

A truck driver is driving too slowly.

ABS is working effectively.

Rollovers happen when a vehicle is driven too fast. To reduce the risk of rollover, make sure the weight of cargo is loaded low to the ground, and that you take turns and curves slowly.

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