Are more likely to roll over than empty rigs.

Are less likely to roll over than empty rigs.

Are just as likely to roll over as empty rigs.

Prevents air from escaping an air brake system.

Is located on the front of a trailer.

Is located on the instrument panel.

Pennsylvania CDL Combination 1 - DMV Written Test Questions with Answers

Q.1

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.

Q.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.

Q.3

In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when:

Air pressure drops to a level between 20 and 45 psi.
You are experiencing a trailer jackknife.
Wheels have regained traction after a skid.
Air pressure is above 45 psi.

Q.4

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.

Q.5

When driving a bobtail tractor, you should be aware that:

Bobtails stop very easily.
Bobtails cannot drive as fast as tractors with semitrailers.
Bobtails are more difficult to stop than tractors with semitrailers.
Bobtails are illegal in most states.

Q.6

When a combination vehicle goes around a corner:

The turn should be made as tightly as possible.
The front and rear wheels move in different paths.
The rear wheels should run over the curb.
It is acceptable for street signs to be knocked over if they are too close to the road.

Q.7

When connecting a converter dolly to a second or third trailer, the trailer height should be:

Slightly higher than the center of the fifth wheel.
Level with the center of the fifth wheel.
Slightly lower than the center of the fifth wheel.
Next to the center of the fifth wheel.

Q.8

If a trailer is too high:

It will not make a difference when coupling.
It may not couple correctly.
Coupling will be more secure.
Coupling will be easier.

Q.9

Rollovers happen when:

A truck driver is driving too fast.
The driver of a vehicle in front of a truck is moving to slowly.
A truck driver is driving too slowly.
ABS is working effectively.

Q.10

Fully-loaded rigs:

Are less likely to roll over than empty rigs.
Are more likely to roll over than empty rigs.
Are just as likely to roll over as empty rigs.
Should not be driven.

Q.11

Air pressure in the ____ air line is controlled by either the foot brake or trailer hand brake.

Emergency
Service
Rear
Auxiliary

Q.12

A lightly-loaded combination vehicle will stop more slowly than a fully-loaded vehicle because:

The stiff suspension springs and strong brakes will have high traction.
The stiff suspension springs and strong brakes will have low traction.
The brakes only operate when a trailer reaches a minimum weight.
The suspension springs only operate when a trailer reaches a minimum weight.

Q.13

Trailers with low underneath clearance may be difficult to drive:

On interstate highways.
Over railroad crossings.
On dirt roads.
At the posted speed limit.

Q.14

A shut-off valve:

Is located on the front of a trailer.
Is located on the instrument panel.
Prevents air from escaping an air brake system.
Should always be open.

Q.15

A combination vehicle has:

One air line.
Two air lines.
Three air lines.
Four air lines.

Q.16

Driving a combination vehicle ____ than driving a single vehicle.

Is easier
Requires more driving skill
Is better for training
Is safer in inclement weather

Q.17

An Anti-Lock Braking System (ABS):

Allows wheels to lock up.
Prevents wheels from locking up.
Makes it easier to turn a large vehicle.
Assists with the operation of brake lights.

Q.18

A trailer will be most likely to swing around when:

It is full.
Traveling in a straight line.
It is empty.
The wheels are rotating.

Q.19

Push in the trailer air supply control to:

Activate the emergency brakes.
Deactivate the air brakes.
Sound the horn.
Supply the trailer with air.

Q.20

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.