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.

Texas CDL Combination 1 - DMV Written Test Questions with Answers

Q.1

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.2

The easiest way to recognize that your trailer has begun to skid is to:

Ask another driver.
Use your mirrors to determine if the trailer has left the lane.
Release the brake pedal and then push it down again.
Watch the jackknife warning light on the control panel.

Q.3

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.4

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.5

Using the trailer hand valve while driving:

Will help you turn safely.
Will stop your trailer safely.
Can cause a skid.
Is impossible.

Q.6

An air supply control in its "emergency" position will:

Turn on the air supply.
Apply the trailer emergency brakes.
Prevent a skid.
Accelerate the vehicle.

Q.7

Which type of vehicle is most prone to the “crack-the-whip” effect?

A five-axle tractor semi-trailer
A three-axle tractor semi-trailer
A bobtail tractor
A triple trailer

Q.8

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.

Q.9

The service air line is attached to the:

Relay valves.
Supply line.
Emergency air line.
Steering wheel.

Q.10

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.11

When entering or crossing traffic while driving a combination vehicle, it is especially important that you:

Sound your horn.
Make sure there is a large enough gap for your vehicle.
Expect other drivers to make room for your vehicle.
Let other drivers wave you into their lane.

Q.12

Large combination vehicles take the longest amount of time to stop:

When fully loaded.
When partially loaded.
When empty.
When mostly loaded.

Q.13

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.14

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.15

One way to prevent a rollover is to:

Move cargo to the left side of the rig.
Keep cargo centered on the rig.
Move cargo to the right side of the rig.
Keep cargo as far from the ground as possible.

Q.16

The trailer hand valve should be used:

To test the trailer brakes.
To check the connection between the trailer and tractor.
To accelerate.
To test the lights on the trailer.

Q.17

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.18

Failure to keep the fifth wheel plate properly greased could:

Cause the trailer to disconnect.
Cause steering problems.
Cause braking problems.
Affect the lights.

Q.19

A tractor protection valve is:

A device that keeps air in the tractor or truck brake system, should the trailer break away or develop a bad leak.
A device that prevents theft.
A device that controls fuel levels.
A device that allows the battery to recharge efficiently.

Q.20

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.