PENNSYLVANIA CDL COMBINATION PRACTICE TEST

11. When the tractor protection valve closes, the trailer _______ brakes will come on.
service
emergency
hand
parking
12. You supply air to the trailer brake system by:
pushing in the trailer air supply knob.
pulling out the trailer air supply valve.
connecting the tractor service air line to the trailer service glad hand.
plugging the electrical cord into the trailer.
13. If you have convex mirrors, be aware that:
everything appears smaller in a convex mirror than it would if you were looking at it directly.
objects seem closer than they really are.
in a convex mirror objects appears larger than they really are.
objects may appear to be faster than they really are.
14. When backing a trailer on a curved path you should back towards:
either side.
neither side (back up straight).
the passenger's side.
the driver's side.
15. When the ______ closes, it stops any air from going out of the tractor.
height control valve
alcohol evaporator
hand valve
tractor protection valve
16. When driving a 50 foot combination vehicle at 50 mph in ideal conditions, you should keep at least ____ seconds of space in front of you.
4
6
5
10
17. When driving on slippery roads, you should NOT:
go slowly.
watch far enough ahead to keep a steady speed.
try to anticipate stops early.
use the engine brake.
18. The trailer hand valve should be used only:
only in combination with the foot brake.
when the trailer is fully loaded.
to test the trailer brakes.
in driving to prevent skids.
19. After supplying air to the trailer brake system, you should check the brake system for crossed air lines by:
applying and releasing the trailer brakes and listening for the sound of trailer brakes.
checking the air brake system pressure gauge for signs of major air loss.
shutting the engine off so you can hear the brakes.
All of the above.
20. What factors can cause brakes to fail or fade?
Brakes out of adjustment
Not relying on the engine braking effect
Excessive use of the service brakes
All of the above.
GRADE ME
NOT SURE YOU WILL PASS? GET CDL PREMIUM NOW! - Learn More