Prevent air from escaping air brake systems.

Prevent air from entering air brake systems.

Override vehicles that are out of control.

Are more likely to roll over than empty rigs.

Usually are very responsive to steering.

New Mexico CDL Combination 2 - DMV Written Test Questions with Answers

Q.1

What is a bobtail tractor?

A tractor without a semi-trailer
A tractor with two semi-trailers
A tractor that travels faster than the speed limit

Q.2

To find out if a vehicle that was built before 1998 has an Anti-Lock Braking System (ABS), you can:

Pump the air brakes to activate the ABS.
Look into the back of the fifth wheel.
Check for wheel speed sensors coming from the back of the brakes.

Q.3

Trailers built before ____ are not required to have spring brakes.

1985
1975
1999

Q.4

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.
75 and 105 psi.
50 and 65 psi.

Q.5

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

Rollovers.
Slippery roads.
Other drivers.

Q.6

Watching the road ahead:

Is more dangerous than only watching your mirrors.
Does not help you drive more safely.
Can help you avoid the need for sudden lane changes.

Q.7

When braking while pulling a trailer equipped with anti-lock brakes, you should:

Pump the brakes.
Use extra braking force to ensure the brakes kick in.
Brake as you would without anti-lock brakes.

Q.8

When glad hands are coupled, the seals should be pressed together at a ____ angle.

50-degree
180-degree
90-degree

Q.9

During a trip, landing gear should be:

Completely raised.
Completely lowered.
Skimming the pavement.

Q.10

Shut-off valves:

Prevent air from escaping air brake systems.
Prevent air from entering air brake systems.
Override vehicles that are out of control.

Q.11

When coupling a trailer, you should:

Couple together the proper glad hands.
Couple glad hands with any other glad hands.
Leave one pair of glad hand loose.

Q.12

Operating combination vehicles usually requires ____ operating single vehicles.

Less skill than
About the same level of skill as
More skill than

Q.13

Fully-loaded rigs:

Usually are very responsive to steering.
Are more likely to roll over than empty rigs.
Can stop quickly.

Q.14

Having anti-lock brakes on only one axle:

Will not make a difference in braking.
Will provide increased control in braking.
Will likely cause the air brakes to malfunction.

Q.15

Older trailers are not equipped with spring brakes. This means that if the air supply for a vehicle's air braking system leaks away:

The trailer will stop normally.
The trailer will not have brakes.
The trailer will speed up.

Q.16

The trailer hand valve should not be used while you are driving because:

It will disconnect from the vehicle.
You will stop the vehicle too quickly.
It can cause a skid.

Q.17

The emergency air line supplies air to the:

Relay valves.
Trailer air tanks.
Signal line.

Q.18

If color-coded, which color is used to identify service lines?

White
Yellow
Blue

Q.19

The tractor protection valve:

Ensures that oil adequately lubricates the engine.
Protects the tractor from exceeding a set speed.
Keeps air in the truck braking system if the trailer develops a leak.

Q.20

Rearward amplification refers to:

The amount of noise projected to the rear of the vehicle.
The cause of the "crack-the-whip" effect.
The number of trailers that can be pulled by one tractor.