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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!

Should the shut-off valves on the rear of the last trailer be open or closed?
  • The service line should be open and the emergency line should be closed
  • The service line should be closed and the emergency line should be open
  • Both the service line and emergency line should be in the closed position
  • Both the service line and emergency line should be in the open position
This is a question from page 59 - click here to look up the answer

Quote From Page 83 Of The Illinois CDL Manual:

Check air flow to all trailers: Use the tractor parking brake and or chock the wheels to hold the vehicle. Wait for air pressure to reach normal, then push in the red "trailer air supply" knob. This will supply air to the emergency (supply) lines. Use the trailer handbrake to provide air to the service line. Go to the rear of the rig. Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged. Close the emergency line valve. Open the service line valve to check that service pressure goes through all the trailers (this test assumes that the trailer handbrake or the service brake pedal is on), then close the valve. If you do NOT hear air escaping from both lines, check that the shut-off valves on the trailer(s) and dolly (5) are in the OPEN position. You MUST have air all the way to the back for all the brakes to work.

TruckingTruth's Advice:

All shut-off valves on the rear most trailer should always be in the closed position.

Next
The shut-off valves on the middle trailer when pulling triple trailers should be in which position?
  • The service line should be closed but the emergency line should be open
  • The service line should be open but the emergency line should be closed
  • Both the service line and emergency line should be in the open position
  • Both the service line and emergency line should be in the closed position
This is a question from page 59 - click here to look up the answer

Quote From Page 83 Of The Illinois CDL Manual:

Check air flow to all trailers: Use the tractor parking brake and or chock the wheels to hold the vehicle. Wait for air pressure to reach normal, then push in the red "trailer air supply" knob. This will supply air to the emergency (supply) lines. Use the trailer handbrake to provide air to the service line. Go to the rear of the rig. Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged. Close the emergency line valve. Open the service line valve to check that service pressure goes through all the trailers (this test assumes that the trailer handbrake or the service brake pedal is on), then close the valve. If you do NOT hear air escaping from both lines, check that the shut-off valves on the trailer(s) and dolly (5) are in the OPEN position. You MUST have air all the way to the back for all the brakes to work.

TruckingTruth's Advice:

Unless it is the very last trailer, all shut-off valves should remain in the open position so that all trailers have proper airflow in the air brake system.

Prev
Next
When pulling two or more trailers, the shut off valves on the first trailer should be in the following positions:
  • Both the service line and the emergency line should be closed
  • Both the service line and the emergency line should be open
  • The service line should be closed and the emergency line should be open
  • The service line should be open and the emergency line should be closed
This is a question from page 59 - click here to look up the answer

Quote From Page 83 Of The Illinois CDL Manual:

Check air flow to all trailers: Use the tractor parking brake and or chock the wheels to hold the vehicle. Wait for air pressure to reach normal, then push in the red "trailer air supply" knob. This will supply air to the emergency (supply) lines. Use the trailer handbrake to provide air to the service line. Go to the rear of the rig. Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged. Close the emergency line valve. Open the service line valve to check that service pressure goes through all the trailers (this test assumes that the trailer handbrake or the service brake pedal is on), then close the valve. If you do NOT hear air escaping from both lines, check that the shut-off valves on the trailer(s) and dolly (5) are in the OPEN position. You MUST have air all the way to the back for all the brakes to work.

TruckingTruth's Advice:

Unless it is the very last trailer, all shut-off valves should remain in the open position so that all trailers have proper airflow in the air brake system.

Prev
Next
The following are proper steps to connecting the converter dolly to the front trailer, except:
  • Lock pintle hook
  • Hook dolly to front trailer
  • Secure converter gear support in the lowered position
  • Back first semi-trailer into position in front of dolly tongue
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 front trailer:

  • Back first semi-trailer into position in front of dolly tongue.
  • Hook dolly to front trailer.
  • Lock pintle hook.
  • Secure converter gear support in raised position
Prev
Next
Why do you need to manage your space better while pulling doubles/triples?
  • Doubles / triples tend to be blown around more during windy conditions
  • Doubles / triples take up more space in turns
  • Doubles / triples require more stopping distance to avoid a jackknife
  • All of these answers are correct
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.

Prev
Next
Do converter dollies have spring brakes?
  • While some states don't require dollies to have spring brakes, it is required for dollies to have spring brakes on the interstate system
  • All converter dollies are required to have spring brakes if built after 1975
  • Converter dollies don't ever have spring brakes
  • Some converter dollies have spring brakes, but dollies are not required to have them
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.

  • Release dolly brakes by opening the air tank petcock. (Or, if the dolly has spring brakes, use the dolly parking brake control.
Prev
Next
All of the following are correct steps to positioning the converter dolly in front of the second (rear) trailer except:
  • Be sure the pintle hook is unlocked
  • Move the dolly to rear of first trailer and couple it to the trailer
  • Wheel dolly into position in front of second trailer in line with the kingpin
  • Pull dolly into position as close as possible to nose of the second semitrailer
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
Prev
Next
When making a visual check of the coupling, all of the following inspections are correct, except:
  • Make sure there is enough grease
  • Be certain the locking jaws are around shank and not the head of the kingpin
  • Check that there is no visible space between the upper and lower fifth wheel
  • 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
Prev
Finish
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[3,3,2,3,4,4,1,4]
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