Compared with a straight truck or bus, there are ___ things to inspect in combination vehicles

a) The same number of

b) Fewer

c) More

Answer: c) More

The service line

a) Carries air to the cab of the rig to cool it

b) Carries air to the parking brake to control the trailer brakes

c) Carries air to a relay valve that allows the trailer brakes to be applied quickly

Answer: c) Carries air to a relay valve that allows the trailer brakes to be applied quickly

You should not back a tractor under a trailer until the whole air system is

a) At normal pressure

b) Between 60 and 80 psi

c) Bled down to half the maximum pressure

Answer: a) At normal pressure

You are coupling a tractor to a semi-trailer. You have connected the air lines. Before backing under the trailer, you should

a) Pull ahead to test the glad hands connections

b) Supply air to the trailer system and then pull out the air supply knob

c) Make sure that the trailer brakes are off

Answer: b) Supply air to the trailer system and then pull out the air supply knob

For coupling to be completed, the safety catch for the fifth wheel locking lever must be

a) Through the locking lever

b) Over the locking lever

c) Straight up

Answer: b) Over the locking lever

The trailer hand valve works the trailer brakes. Which of these statements is true?

a) The trailer hand valve should be used only to test the trailer brakes

b) The foot brake sends air to all the brakes on the vehicles (including the trailer(s)).

c) Both of these statements are true

Answer: c) Both of these statements are true

You should not use the trailer hand valve while driving because

a) It won't work as well as the foot brake

b) You should use the parking brake

c) Of the danger of making the trailer skid

Answer: c) Of the danger of making the trailer skid

What is the emergency air line?

a) Air lines connecting the parking brake to the trailer brakes

b) Air lines that control the emergency brakes on combination vehicles

c) Air lines that control the emergency brakes of the tractor

Answer: b) Air lines that control the emergency brakes on combination vehicles

After the trailer has been coupled to the tractor, the tractor protection control valve should be placed in what position?

a) Down

b) Normal

c) Up

Answer: b) Normal

You supply air to the trailer tanks by

a) Pulling out the trailer air supply valve

b) Pushing in the trailer air supply valve

c) Connecting the service line glad hand

Answer: b) Pushing in the trailer air supply valve

Glad hands are used to connect the

a) Electrical lines from the tractor to the trailer

b) Service and emergency air lines from the truck or tractor to the trailer

c) Kingpin from the trailer to the locking jaws of the fifth wheel

Answer: b) Service and emergency air lines from the truck or tractor to the trailer

Under good driving conditions, you should leave at least one second of space between your vehicle and the vehicle ahead for every ___ feet of your vehicle's length

a) 10

b) 30

c) 20

Answer: a) 10

After you supply air to the trailer, make sure the air lines are not crossed and the trailer brakes are working. This is done by

a) Applying and releasing the trailer brakes and listening for brake sounds

b) Turning on the parking brakes from the cab

c) Lifting the brake pedal

Answer: a) Applying and releasing the trailer brakes and listening for brake sounds

You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You would expect the trailer brakes to come on and

a) The tractor to lose all air pressure

b) The trailer supply valve to stay open

c) The tractor protection valve to close

Answer: c) The tractor protection valve to close

A trailer is most likely to jackknife when it is

a) Loaded to full capacity

b) Empty

c) Overloaded

Answer: b) Empty

The front trailer supports are up, and the trailer is resting on the tractor. Make sure that

a) The safety latch is in the unlocked position

b) There is enough clearance between the tractor frame and the landing gear

c) There is enough clearance between the upper and lower fifth wheel

Answer: b) There is enough clearance between the tractor frame and the landing gear

Air lines on a combination vehicle are often colored to keep them from getting mixed up. The emergency line is ___; the service line is ___.

a) Back; yellow

b)Blue; red

c) Red; blue

Answer: c) Red; blue

While you are driving, your emergency air line breaks or gets pulled apart. The loss of pressure will cause the

a) Trailer supply valve to open

b) Air compressor to unload instead of pumping air

c) Trailer emergency brakes to come on

Answer: c) Trailer emergency brakes to come on

Describe what the trailer air supply controls does

a) It is a device used to keep the trailer behind the tractor

b) It is used to supply the trailer with air, shut the air off, and apply the trailer emergency

c) It is a six-sided yellow knob used to control the tractor protection valve

Answer: b) It is used to supply the trailer with air, shut the air off, and apply the trailer emergency

If the brakes did not release when you pushed the trailer air supply valve, you should

a) Check the air line connections

b) Cross the air lines

c) Check the electrical cables

Answer: a) Check the air line connections