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 Nebraska 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 25 multiple-choice questions, and applicants will need to correctly answer a minimum of 20 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question 25

Passing Score 20

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. What does the trailer air supply control look like?

It is a square blue knob.

It is a triangular yellow knob.

It is an eight-sided red knob.

It is a circular orange knob.

On newer vehicles, the trailer air supply control is an eight-sided red knob. It's used to control the tractor protection valve.

3. After finishing a pre-trip inspection, you should:

Leave the rear shut-off valves open.

Remove the service line valve.

Close the emergency line valve.

Leave the emergency line valve open.

Before a trip, you should ensure that air reaches all air brakes on all trailers by opening up the rear emergency line and service line shut-off valves to listen for escaping air. Close both shut-off valves before beginning to drive.

4. When traveling more slowly than 40 mph, maintain at least ____ of following distance per every 10 feet of your vehicle.

One second

Two seconds

Three seconds

Four seconds

At speeds below 40 mph, you should allow at least one second of following distance for every 10 feet of your vehicle. Follow the same formula when traveling at faster speeds, then add one additional second to your following distance. Remember that larger vehicles require more space to stop than smaller vehicles.

5. 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.

6. Using the trailer hand brake while experiencing a trailer jackknife will:

Stop the skid.

Straighten the trailer.

Increase traction.

Continue the skid.

If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.

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