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 Texas Commercial Motor Vehicle Drivers Handbook. 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. Driving a combination vehicle ____ than driving a single vehicle.

Is easier

Requires more driving skill

Is better for training

Is safer in inclement weather

Driving a combination vehicle usually requires more skill than driving a single vehicle. Combination vehicles are generally longer and heavier than single commercial vehicles.

2. The easiest way to recognize that your trailer has begun to skid is to:

Ask another driver.

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

Release the brake pedal and then push it down again.

Watch the jackknife warning light on the control panel.

The easiest way to spot a trailer skid is to use your mirrors. Any time you brake hard, check your mirrors to ensure that your trailer is still in its proper position.

3. When coupling a trailer:

Make sure to couple matching glad hands.

Any glad hand can be connected to any other glad hand.

It is best to leave one glad hand unattached.

Only one set of glad hands should be connected.

When coupling, make sure you couple matching glad hands. They are often color-coded to help drivers avoid mistakes. Typically, blue is used for service lines and red is used for emergency lines.

4. The trailer hand valve:

Should always be used for parking.

Should only be used for parking on a downhill.

Should never be used for parking.

Should only be used when transporting cargo.

The trailer hand valve should not be used for parking. This could cause all of the air to leak out of the braking system, resulting in the brakes releasing. Instead, use the parking brake.

5. Using the trailer hand valve while driving:

Will help you turn safely.

Will stop your trailer safely.

Can cause a skid.

Is impossible.

Never use the trailer hand valve while operating your vehicle. Using the trailer hand valve while driving can cause your trailer to skid.

6. An air supply control in its "emergency" position will:

Turn on the air supply.

Apply the trailer emergency brakes.

Prevent a skid.

Accelerate the vehicle.

Tractor protection controls in older vehicles may be operated by levers instead of knobs. If an air supply control is set in its "emergency" position, the air supply will be stopped and the trailer emergency brakes will be applied.