Combination Vehicles

1.

1 point

Which of these statements is true?

bobtail tractors can take longer to stop than a combination vehicle loaded to maximum gross weight.

the brakes and suspension systems of combination vehicles work best with a light load.

Light vehicles need more braking power to stop than heavy ones

2.

1 point

The tractor protection valve will close and the trailer emergency brakes will come on when there is a major leak in the

emergency brake line

parking brake line

service brake line

3.

1 point

When backing a tractor under a trailer you should:

always approach the trailer at a slight angle

always use the lowest reverse gear

do it quickly to ensure that the kingpin is locked into the fifth wheel

4.

1 point

There are two things that a driver can do to prevent a rollover. They are: (1) keep the cargo as close to the ground as possible; and (2):

go slow around turns

keep both hands firmly on the steering wheel

make sure that the brakes are properly adjusted

5.

1 point

How much space should be allowed between upper and lower fifth wheel after coupling?

nothing

one and a quarter inch

just enough to sit on

6.

1 point

To stop a trailer skid you should:

use the trailer hand brakes

counter steer

release the service brakes.

7.

1 point

When you are uncoupling a loaded trailer you should lower the landing gear until it:

makes firm contact with the ground, then with the crank in a low gear a few extra turns

reaches the ground

make contact with the ground and leave the trailer off the fifth wheel

8.

1 point

Why should you lock the tractor glad hands to each other (or dummy couplers) when you are not towing a trailer?

the connected brake circuit becomes a back up air tank.

it will keep dirt or water out of the lines

if you didn't, you could never build system pressure

9.

1 point

A tractor with a (Blank) trailer requires the shortest amount of stopping distance.

fully loaded

partly loaded

empty

10.

1 point

The trailer supports are up and the trailer is resting on the tractor. Make sure:

there is enough clearance between the upper and lower fifth wheels

the is enough clearance between the tractor frame and the landing gear

the safety latch is in the unlocked position

11.

1 point

Why should you be sure that the fifth wheel plate is greased as required?

to prevent steering problems

to reduce heat and noise

to ensure a good electrical connection

12.

1 point

In normal driving, some drivers use the hand valve before the brake pedal to prevent a jackknife. Which of the statements is true?

it should not be done.

it results in less skidding than using the brake pedal alone

it is the best way to brake and keep the truck in a straight line

13.

1 point

If the brakes are not released when you pushed the trailer air supply valve you should:

check electrical cable

cross the airlines

check air line connection

14.

1 point

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:

applying and releasing the trailer brakes and listening for the sound of the brake.

lifting the brake pedal.

watching your mirrors to see if the trailer lights come on.

15.

1 point

A driver crosses the air lines when hooking up to a trailer, what will happen?

The brake lights will come on when the brake pedal is pressed

if the trailer has no spring brakes, you could drive away but you wouldn't have trailer brakes.

The hand valve will apply the tractor brakes instead of the trailer brakes

16.

1 point

You are coupling a tractor to a semitrailer and have backed up but are not under it. What should you hook up before backing under?

nothing. Back up and lock the fifth wheel.

The emergency and service air lines

the electrical service cable

17.

1 point

The air leakage rate for a combination vehicle (engine off, brakes on) should be less than (blank) psi per minute.

four

three

two

five

18.

1 point

If the service line comes apart while you are driving a combination vehicle, but the emergency line stays together, what will happen right away?

nothing is likely to happen until you try to apply the brakes.

the emergency trailer brakes will come on.

the trailer's tank will exhaust through the open line.

19.

1 point

Before you back under a trailer, make sure that:

the tractor protection valve is normal

the trailer brakes are locked.

the air supply knob is in.

20.

1 point

Off-tracking or cheating causes of which of these to need a wider pass while making a turn?

tractor with two 27' trailers

triple towing 45' trailers

53' bobtail

21.

1 point

You have pushed the trailer air supply valve. You should not back a tractor under a trailer until the whole air supply system is:

empty

between 60 and 80 psi.

at normal pressure

22.

1 point

Air and electrical lines from the tractor to the trailer should be:

fully tight but away a little looped

secured but with enough loop to turn

resting on the frame of the tractor

23.

1 point

When should you use the hand valve to park a combination vehicle?

to park on a grade

to park a loading docks

never

24.

1 point

After you lock the kingpin into the fifth wheel, you should check the connection by:

pulling forward 50 feet, turning right and then left

pulling the tractor ahead gently with the trailer brakes locked

backing up with the trailer brakes released.

25.

1 point

The safest way to make a turn without entering another traffic lane is:

you should turn wide before you start the turn.

you should not make a turn and move to another place where you can make a turn without crossing other lane.

you should turn wide as you complete the turn.

26.

1 point

The hand valve should be used:

only with a foot brake

to test the trailer brakes

as a parking brake

27.

1 point

The air brake leakage rate for a combination vehicle(engine off, brakes off) should be less than (blank) psi per minute.

2

3

1/2

1

28.

1 point

How should you test the tractor-semitrailer connection for security?

look at it carefully

rock the trailer back and forth with the trailer brakes locked

pull gently forward in low gear against the locked trailer brakes then look at it carefully.

29.

1 point

You supply air to the trailer tanks by:

connecting the service line glad hands

pulling out the trailer air supply valve

pushing in the trailer air supply valve

30.

1 point

When driving a set of doubles it is necessary to close which shut-off valve in the last trailer?

middle section

back

front

31.

1 point

After connecting the air lines but before backing under the trailer you should:

walk around the rig to be sure that it is clear.

make sure that the trailer brakes are off.

supply air to the trailer system, then pull out the air supply knob.

32.

1 point

You have a major leak in the service line and you put on the brakes. Service air will escape and cause the:

trailer brakes to come one

trailer tank pressure to be lost

tractor spring brakes to lock up

33.

1 point

When connecting the glad hands press the two seals with the coupler together at what degree to each other?

180 degrees

40 degrees

90 degrees

34.

1 point

You are about to back your tractor under a semitrailer. The trailer is at the right height when the:

end of the kingpin is even with the top of the fifth wheel.

trailer will be lifted slightly when the tractor backs under it.

kingpin is about one and a quarter inch above the fifth wheel

35.

1 point

While checking if the trailer is securely coupled to the trailer, the landing gear should be:

fully raised

fully lowered

slightly raised

36.

1 point

The higher the center of gravity of your truck, the:

easier to turn around the corner

more stable while turning

easier to turn over

37.

1 point

When coupling, the proper position of the fifth wheel is:

level with the ground

tilted up toward the end of the trailer.

tilted down toward the end of the trailer

38.

1 point

After you have coupled the trailer you should have to raise the landing gear by using:

intermediate gear

low gear

high gear

39.

1 point

A semi-trailer made before 1975 that is equipped with air brakes:

often do not have spring brakes

have only a service air line

usually need a glad hand converter

40.

1 point

The air lines on a combination vehicles are often colored to prevent them from getting mixed up. The emergency line is (Blank), the service line is (blank).

red, blue

blue, red.

black, yellow

41.

1 point

Glad hands are usually connecting which of these?

electric lines from the tractor to trailer

service and emergency air lines from the vehicle to the trailer.

kingpin from the trailer to the locking jaws of the fifth wheel

42.

1 point

To unlock the fifth wheel the locking lever should be placed in the:

neutral position

open position

closed position

43.

1 point

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

normal

down

up

44.

1 point

Where should the tractor be when you inspect landing gear after uncoupling the trailer?

with the fifth wheel directly beneath the kingpin

with the tractor frame under the trailer

completely cleared from the trailer

45.

1 point

Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the:

trailer supply valve to open.

air compressor to unload instead of pumping air

emergency trailer brakes to come on

46.

1 point

Compared to a straight truck there are (Blank) things to inspect in a combination vehicle.

the same number

fewer

more

47.

1 point

There are two things that a driver can do to prevent a rollover. They are: (1) go slow around turns; and (2):

keep the cargo as close to the ground as possible.

keep both hands firmly on the steering wheel

make sure that the brakes are properly balanced

48.

1 point

The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means that:

the trailer will not swivel on the fifth wheel.

the coupling is not right and should be fixed before driving the coupled unit.

the parking lock is off and you may drive away.

49.

1 point

You're driving a 60' combination vehicle at 47 mph, how much following distance should you have behind the vehicle in front of you?

6 seconds

5 seconds

7 seconds

8 seconds

50.

1 point

You have coupled with a semitrailer. Where should you put the iron trailer supports before driving away?

fully raised with the crank handle secured in its bracket

raised 1/2 way with the crank handle secured in its bracket

3 turns off the top with the crank handle secured in its bracket.