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 New Hampshire CDL.. 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 New Hampshire CDL Driver's Guide. 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 have 30 minutes to correctly answer a minimum of 16 questions. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question 20

Passing Score 16

1. What is another name for the service line?

The control line

The utility line

The open line

The parallel line

The trailer service air line may also be referred to as the control line or signal line.

2. 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.

3. What is a tractor protection valve?

A valve to keep air in the brake system should there be a bad leak

A valve that prevents the truck from being stolen

A valve that prevents the driver from going too fast

A valve that prevents the trailer from accidentally being released

In a combination vehicle with air brakes, the tractor protection valve keeps air in the tractor or truck brake system in the event of the trailer breaking away or developing a leak.

4. Trailers with low underneath clearance may be difficult to drive:

On interstate highways.

Over railroad crossings.

On dirt roads.

At the posted speed limit.

Railroad-highway crossings may be difficult to cross when pulling a trailer with a low underneath clearance. In particular, both low-slung units and single-axle tractors pulling long trailers are especially challenging to drive over raised crossings.

5. The service air line is attached to the:

Relay valves.

Supply line.

Emergency air line.

Steering wheel.

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.

6. When lightly loaded, combination vehicles:

Should not be driven.

Have reduced braking capabilities.

Will not rollover.

Should be loaded with most of the weight in the rear of the trailer.

When a combination vehicle is lightly loaded, it may have poor traction. It is very easy for wheels to lock up on lightly-loaded vehicles when they are being stopped.

7. Test the tractor protection valve by:

Removing the air supply knob.

Removing the parking brake control knob.

Releasing air with the brake pedal.

Releasing air with the gas pedal.

You should test the tractor protection valve by allowing the air supply to properly charge, turning off the engine, then releasing air from the system by pressing the brake pedal several times. The tractor protection valve should move into its emergency position when psi drops to an unsafe level.

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