CDL Combination Vehicles Practice Test Results

Question 1
82% answer correctly
Before backing under a trailer that you`ve just hooked to your tractor you should:
Hook up the electrical lines
Ground the trailer
Make sure the fifth wheel has been removed
Hook up the service and emergency lines
Question 2
75% answer correctly
The locking jaws should close around the __________ of the kingpin.
Neck
Top
Base
Shank
Question 3
87% answer correctly
In which of the following circumstances should the valve hand be used to park a combination vehicle?
When parked on a grade
When unloading
Never
When parking for less than 10 minutes