CDL Combination Vehicles Practice Test Results

Question 1
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
When parking for less than 10 minutes
Never
Question 2
89% answer correctly
When is the proper time to use the trailer handbrake to straighten out a trailer that`s jackknifing?
When you start to recover from the jackknife
As soon as you start to jackknife
In the middle of the jackknife
Never
Question 3
81% answer correctly
What`s the purpose of the trailer air supply control?
Supplies air to the trailer
Prevents trailers from becoming decoupled
Engages the trailer air brakes
Supplies air to the cab