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 Michigan 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 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. The service air line is often controlled by the foot brake and is attached to the ____ valves.

Relay

Supply

Emergency

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

2. More than half of all accident-related truck driver deaths are caused by:

Rollovers.

Slippery roads.

Other drivers.

More than half of all accident-related truck driver deaths are a result of truck rollovers. To help prevent a rollover, be sure to load cargo low to the ground and centered on your rig. Take corners slowly and carefully.

3. If an air supply control is in its "emergency" position:

The vehicle will increase speed.

The trailer emergency brakes will be applied.

The air supply to the trailer will increase.

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.

4. In a double or triple combination, the ____ trailer should be directly behind the cab.

Lightest

Heaviest

Smallest

When positioning trailers in a combination, the most heavily-loaded trailer should be the closest to the tractor. The lightest trailer should be positioned in the rear.

5. Keeping cargo low can:

Prevent a rollover.

Help you drive faster.

Make turns more dangerous.

Rollovers can happen when a combination vehicle is turned too quickly. To help prevent the risk of rollover, it is important to keep the vehicle's center of gravity low by loading cargo as close to the ground as possible.

6. Combination vehicles need extra space on the road because they:

Drive more slowly than other commercial motor vehicles.

Are heavier than other commercial motor vehicles.

Need more space to turn and stop than other commercial motor vehicles.

Combination vehicles need more space on the road than other commercial vehicles because they are longer and need more space to turn and stop. It is especially important to properly manage space when you are operating a combination vehicle.