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 Minnesota Commercial.. 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 Minnesota Commercial Driver's 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. Before a drive, ensure that air flows to all trailers by:

Opening the rear shut-off valves and listening for escaping air.

Closing the rear shut-off valves and listening for escaping air.

Disconnecting air supply lines and listening for escaping air.

Rolling each trailer down a hill and testing the brakes.

Before a trip, ensure that air in the air brake system reaches all trailers. Do this by waiting for air pressure to build, then sending air to both the emergency and service lines and opening the shut-off valves on the rear of the last trailer. If air escapes from the shut-off valves in the rear of the combination, the air is being supplied to the entire vehicle.

2. If a load is placed on one side of a trailer, the trailer:

May lean during turns.

May add extra support during turns.

May be easier to steer during turns.

Positioning the weight of a load on one side of a trailer may cause the trailer to lean to that side, increasing the risk of a rollover during turns and lane changes.

3. When coupling:

You can assume all vehicles are the same.

Be sure that you are coupling correctly.

Cracks in the mounting are acceptable.

Incorrect coupling and uncoupling of combination vehicles can have extremely dangerous consequences.

4. If a trailer begins to skid, the driver should:

Lock the brakes.

Release the brakes.

Steer in the opposite direction.

Accelerate.

If your trailer starts to skid while you are braking, you should release the brakes and allow them to begin to regain traction. Once its wheels have regained their grip on the road, the trailer will begin to straighten out and follow the tractor.

5. Failure to keep the fifth wheel plate properly greased could:

Cause the trailer to disconnect.

Cause steering problems.

Cause braking problems.

Affect the lights.

Failure to keep the fifth wheel plate properly lubricated can create friction between the tractor and trailer, causing steering problems.

6. If a parked trailer does not have spring brakes, you should keep the trailer from moving by:

Having the vehicle parked against a wall or other vehicle.

Using chock blocks.

Parking on a slight incline.

If a parked trailer does not have spring brakes, wheel chocks should be used to prevent it from moving.

7. If unsure if a trailer is equipped with ABS, you can:

Check under the trailer for wheel speed sensors coming from the back of the brakes.

Try driving on a slippery surface and see if ABS kicks in.

Assume it does have ABS.

Remove a tire and look for the ABS sensor on the axle.

Trailers and converter dollies built on or after March 1, 1998 are required to have Anti-Lock Braking Systems (ABS). This will be indicated by the presence of a yellow malfunction lamp. You can determine if older trailers have ABS by checking under the trailers for ECU and wheel speed sensor wires coming from the back of the brakes.

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