NC CDL LATEST
COMBINATION
VEHICLES
Describe what the trailer air supply control does: - ANSWERS-It is used
to supply the trailer with air, shut the air off, and put on the trailer
emergency brakes.
Describe what the service line is for? - ANSWERS-To carry air to a
relay valve that allows the trailer brakes to be applied quickly.
What are the other names for the service air line? - ANSWERS-Control
line or signal line.
What is the emergency line? - ANSWERS-Air lines that control the
emergency brakes on combination vehicles.
What is the emergency air line for? - ANSWERS-To engage the trailer
brakes in case of an emergency.
Why should you use chocks when parking a trailer without spring
brakes? - ANSWERS-Because is the air pressure leaks away or down,
there will be no brakes.
END OF
PAGE
1
, NC CDL LATEST
COMBINATION
VEHICLES
When a vehicle is carrying a load at night which extends four feet or
more beyond the rear of the body, there must be _____ at the extreme
end of the load. - ANSWERS-2 red lights.
How long does it take a typical tractor-trailer to clear a single track? A
double track? - ANSWERS-It takes 14 seconds to clear a single track,
and more than 15 seconds to clear a double track.
You have pushed in the trailer supply valve. You should not move the
tractor until the whole air system is: - ANSWERS-At normal pressure.
The best way to tell if your trailer has started to skid is to: - ANSWERS-
See it in your mirrors.
Which of these vehicles off-track the most. - ANSWERS-5-axle tractor
towing a 52-foot trailer.
A tractor with a(n) ____ trailer requires the shortest amount of stopping
distance. - ANSWERS-Fully loaded.
END OF
PAGE
2
, NC CDL LATEST
COMBINATION
VEHICLES
A trailer is most likely to jackknife when it is: - ANSWERS-Empty.
If you have coupled with a semi-trailer, where should the front trailer
supports be before driving away? - ANSWERS-Fully raised with the
crank handle secured in its bracket.
The fifth wheel locking lever is not locked after the jaws close around
the kingpin. This means that: - ANSWERS-The coupling is not right and
should be fixed before driving the coupled unit.
You want to inspect the trailer supports. You should place the tractor
transmission in which gear after you have uncoupled the trailer? -
ANSWERS-Neutral.
When should you use chocks to park a trailer not equipped with spring
brakes? - ANSWERS-Always.
You are coupling a semi-trailer to your tractor but have not yet backed
under, the trailer is at the right height when: - ANSWERS-It will be
raised slightly when the tractor is backed under it.
END OF
PAGE
3
COMBINATION
VEHICLES
Describe what the trailer air supply control does: - ANSWERS-It is used
to supply the trailer with air, shut the air off, and put on the trailer
emergency brakes.
Describe what the service line is for? - ANSWERS-To carry air to a
relay valve that allows the trailer brakes to be applied quickly.
What are the other names for the service air line? - ANSWERS-Control
line or signal line.
What is the emergency line? - ANSWERS-Air lines that control the
emergency brakes on combination vehicles.
What is the emergency air line for? - ANSWERS-To engage the trailer
brakes in case of an emergency.
Why should you use chocks when parking a trailer without spring
brakes? - ANSWERS-Because is the air pressure leaks away or down,
there will be no brakes.
END OF
PAGE
1
, NC CDL LATEST
COMBINATION
VEHICLES
When a vehicle is carrying a load at night which extends four feet or
more beyond the rear of the body, there must be _____ at the extreme
end of the load. - ANSWERS-2 red lights.
How long does it take a typical tractor-trailer to clear a single track? A
double track? - ANSWERS-It takes 14 seconds to clear a single track,
and more than 15 seconds to clear a double track.
You have pushed in the trailer supply valve. You should not move the
tractor until the whole air system is: - ANSWERS-At normal pressure.
The best way to tell if your trailer has started to skid is to: - ANSWERS-
See it in your mirrors.
Which of these vehicles off-track the most. - ANSWERS-5-axle tractor
towing a 52-foot trailer.
A tractor with a(n) ____ trailer requires the shortest amount of stopping
distance. - ANSWERS-Fully loaded.
END OF
PAGE
2
, NC CDL LATEST
COMBINATION
VEHICLES
A trailer is most likely to jackknife when it is: - ANSWERS-Empty.
If you have coupled with a semi-trailer, where should the front trailer
supports be before driving away? - ANSWERS-Fully raised with the
crank handle secured in its bracket.
The fifth wheel locking lever is not locked after the jaws close around
the kingpin. This means that: - ANSWERS-The coupling is not right and
should be fixed before driving the coupled unit.
You want to inspect the trailer supports. You should place the tractor
transmission in which gear after you have uncoupled the trailer? -
ANSWERS-Neutral.
When should you use chocks to park a trailer not equipped with spring
brakes? - ANSWERS-Always.
You are coupling a semi-trailer to your tractor but have not yet backed
under, the trailer is at the right height when: - ANSWERS-It will be
raised slightly when the tractor is backed under it.
END OF
PAGE
3
