16. Air brake equipped trailers made before 1975:
Often do not have spring brakes.
17. There are two things that a driver can do to prevent a rollover. They are (1) go slow around turns and (2):
Keep the cargo as close to the ground as possible.
18. After connecting the air lines but before backing under the trailer you should:
Supply air to the trailer system, then pull out the air supply knob.
19. Which part of the kingpin should the locking jaws close around?
The shank.
20. How much space should be allowed between upper and lower fifth wheel after coupling?
Nothing