LA CDL DOUBLES TRIPLES PRACTICE TEST

11. Emergency brakes must be held on by:
hydraulic pressure.
dynamic pressure.
mechanical force.
air pressure.
12. The trolley valve should be used only:
to test the trailer brakes.
in driving.
in an emergency.
to prevent skids.
13. After an accident, an improper use of flares could cause:
the vehicle to slide back and forth.
a fire if spilled fuel is on the ground.
air pressure to build from 50 to 100 psi within 2 minutes.
the springs to put on the brakes.
14. When the wheels of a trailer lock up, which of the following is most likely to occur?
The trailer will tend to swing around (trailer jackknife).
The trailer will tend to push the towing vehicle sideways (tractor jackknife).
The trailer will the trailer has overturn.
The rig will stay in a straight line but slide sideways.
15. Under a pressurized system, the radiator cap:
should never be removed until the system has cooled.
should never be hot.
should be removed when the coolant is hot.
should always be cool.
16. The trailer hand valve should:
never be used for parking.
be used in driving.
never be used to test the trailer brakes.
All of the above.
17. Because of the "crack-the-whip" effect, doubles and triples:
are much slower than other combination vehicles.
are more likely to turn over than other combination vehicles.
are more likely to run out of gas than other combination vehicles.
can go much faster than other combination vehicles.
18. If you cannot make a right turn without entering another traffic lane, you should:
swing wide to the left before starting the turn.
watch out for vehicles coming toward you and back up for them.
turn wide before you start the turn.
turn wide as you complete the turn.
19. If the drive wheels begin to spin, you should:
apply your brakes all the way.
take your foot off the accelerator.
accelerate smoothly and change gears as necessary.
wait 4-5 seconds before applying the accelerator.
20. When inspecting the coupling, how much space should there be between the upper and the lower fifth-wheel?
It depends on the load
None.
½ inch
It depends on the trailer
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