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CDL Practice Test: Doubles And Triples

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CDL Practice Test: Doubles And Triples

Doubles And Triples Questions

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Good Luck!

When making a visual check of the coupling, all of the following inspections are correct, except:
  • Make sure there is enough grease
  • Check that there is no visible space between the upper and lower fifth wheel
  • Be certain the locking jaws are around shank and not the head of the kingpin
  • Ensure the release arm is properly seated and the safety latch is unlocked
This is a question from page 58 - click here to look up the answer

Quote From Page 82 Of The Illinois CDL Manual:

Check fifth wheel (lower)

  • Securely mounted to frame
  • No missing, damaged parts
  • Enough grease
  • No visible space between upper and lower fifth wheel
  • Locking jaws around shank, not head of kingpin
  • Release arm properly seated and safety latch/lock engaged

Check Fifth wheel (upper)

  • Glide plate securely mounted to trailer frame
  • Kingpin not damaged
Next
Why do you need to manage your space better while pulling doubles/triples?
  • All of these answers are correct
  • Doubles / triples take up more space in turns
  • Doubles / triples tend to be blown around more during windy conditions
  • Doubles / triples require more stopping distance to avoid a jackknife
This is a question from page 55 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

Doubles and triples take up more space than other commercial vehicles. They are not only longer, but also need more space because they cannot be turned or stopped suddenly. Allow more following distance. Make sure you have large enough gaps before entering or crossing traffic. Be sure you are clear at the sides before changing lanes.

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Next
All of the following are correct steps to positioning the converter dolly in front of the second (rear) trailer except:
  • Move the dolly to rear of first trailer and couple it to the trailer
  • Pull dolly into position as close as possible to nose of the second semitrailer
  • Wheel dolly into position in front of second trailer in line with the kingpin
  • Be sure the pintle hook is unlocked
This is a question from page 56 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

Position converter dolly in front of second (rear) trailer:

  • Release dolly brakes by opening the air tank petcock. (Or, if the dolly has spring brakes, use the dolly parking brake control.)
  • If the distance is not too great, wheel dolly into position by hand so it is in line with the kingpin.
  • Or, use the tractor and first semitrailer to pick up the converter dolly:
  • Position combination as close as possible to converter dolly.
  • Move dolly to rear of first semi-trailer and couple it to the trailer.
  • Lock pintle hook.
  • Secure dolly support in raised position.
  • Pull dolly into position as close as possible to nose of the second semitrailer.
  • Lower dolly support.
  • Unhook dolly from first trailer.
  • Wheel dolly into position in front of second trailer in line with the kingpin
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Next
How do you check to make sure the trailer height is correct before coupling?
  • The trailer should be a minimum of 1ft higher than the fifth wheel, so the trailer king pin will not strike the fifth wheel plate and cause damage
  • The trailer landing gear should be lowered completely so that you can push the dolly under the trailer and be ready to drive once attached
  • The trailer must be slightly lower than the center of the fifth wheel, so the trailer is raised slightly when dolly is pushed under.
  • The trailer should be slightly higher than the center of the fifth wheel, so the trailer doesn't have to raise up when the dolly is pushed under
This is a question from page 56 - click here to look up the answer

Quote From Page 81 Of The Illinois CDL Manual:

Connect converter dolly to rear trailer:

  • Make sure trailer brakes are locked and/or wheels chocked.
  • Make sure trailer height is correct. (It must be slightly lower than the center of the fifth wheel, so trailer is raised slightly when dolly is pushed under.)
  • Back converter dolly under rear trailer.
  • Raise landing gear slightly off ground to prevent damage if trailer moves.
  • Test coupling by pulling against pin of number two semi-trailer.
  • Make visual check of coupling. (No space between upper and lower fifth wheel. Locking jaws closed on kingpin.)
  • Connect safety chains, air hoses and light cords.
  • Close converter dolly air tank petcock and shut-off valves at rear of second trailer (service and emergency shut-offs).
  • Open shut-off valves at rear of first trailer (and on dolly if so equipped).
  • Raise landing gear completely.
  • Charge trailers (push "air supply" knob in) and check for air at rear of second trailer by opening the emergency line shut-off. If air pressure is not there, something is wrong and the brakes will not work.
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Next
What is a converter gear or dolly?
  • A special accessory used to supply hydraulic pressure to the rear trailer brakes
  • A coupling device of one or two axles and a fifth wheel by which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig.
  • A special device to indicate any airline failures or leaks in the rear most trailer
  • An anti-jackknife braking system similar to ABS used in the second and/or third trailer
This is a question from page 56 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

A converter gear or dolly is a coupling device of one or two axles and a fifth wheel by which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig.

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Next
Which of the following shut off valve positions is incorrect?
  • Converter dolly air tank drain valve: CLOSED
  • Rear of last trailer: CLOSED
  • Rear of front trailers: OPEN
  • All of these are correct
This is a question from page 58 - click here to look up the answer

Quote From Page 83 Of The Illinois CDL Manual:

Double and triple trailers:

  • Shut-off valves (at rear of trailers, in service and emergency lines)
  • Rear of front trailers: OPEN
  • Rear of last trailer: CLOSED
  • Converter dolly air tank drain valve: CLOSED
  • Air lines supported and glad hands properly connected
  • If spare tire is on converter gear (dolly), make sure it is secured
  • Pintle-eye of dolly in place in pintle hook of trailer(s)
  • Pintle hook latched
  • Safety chains secured to trailer(s)
  • Light cords firmly in sockets on trailers
Prev
Next
Which of the following is true about pulling double or triple trailers?
  • Doubles/triples are easier to handle in windy conditions than single trailer vehicles
  • Doubles/triples are less prone to rollovers than single trailer vehicles
  • Doubles/triples don't jackknife as easily as single trailer vehicles
  • Doubles/triples are less stable than other commercial vehicles
This is a question from page 55 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

Take special care when pulling two and three trailers. There are more things that can go wrong, and doubles/triples are less stable than other commercial vehicles. Some areas of concern are discussed below.

TruckingTruth's Advice:

Pulling doubles or triples are much more dangerous in nearly every aspect of driving, which is why they require an additional endorsement. Be extra cautious when driving a truck with two or more trailers.

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Next
Which of these steps to connecting the converter dolly to the rear trailer is incorrect?
  • Connect safety chains, air hoses and light cords
  • Make sure trailer brakes are locked and/or wheels chocked
  • Close shut-off valves at rear of first trailer (and on dolly if so equipped)
  • Back converter dolly under rear trailer
This is a question from page 56 - click here to look up the answer

Quote From Page 81 Of The Illinois CDL Manual:

Connect converter dolly to rear trailer:

  • Make sure trailer brakes are locked and/or wheels chocked.
  • Make sure trailer height is correct. (It must be slightly lower than the center of the fifth wheel, so trailer is raised slightly when dolly is pushed under.)
  • Back converter dolly under rear trailer.
  • Raise landing gear slightly off ground to prevent damage if trailer moves.
  • Test coupling by pulling against pin of number two semi-trailer.
  • Make visual check of coupling. (No space between upper and lower fifth wheel. Locking jaws closed on kingpin.)
  • Connect safety chains, air hoses and light cords.
  • Close converter dolly air tank petcock and shut-off valves at rear of second trailer (service and emergency shut-offs).
  • Open shut-off valves at rear of first trailer (and on dolly if so equipped).
  • Raise landing gear completely.
  • Charge trailers (push "air supply" knob in) and check for air at rear of second trailer by opening the emergency line shut-off. If air pressure is not there, something is wrong and the brakes will not work.
Prev
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