CDL Combination Test (2024) - FREE Idaho CDL Practice Test

1. When you turn suddenly while pulling doubles, which trailer is most likely to turn over?

All trailers are equally likely to turn over.
The rear trailer is twice as likely to turn over as the tractor.
The front trailer is twice as likely to turn over as the tractor.

2. What is a tractor jackknife?

When the wheels of a trailer lock up, and the trailer swings around.
When a drive-wheel skid lets the trailer push the towing vehicle sideways.
None of the above.

3. Anti-lock brakes:

keep your brakes from locking up when you brake hard.
help you stop faster.
increase your stopping distance.

4. How do you find out how many seconds of following distance you have?

Wait until the vehicle ahead of you passes a pavement marking, shadow or landmark. Then count off the seconds until you reach the same spot.
Pass a stationary object and count how many seconds it takes the vehicle ahead of you to reach the same spot.
Wait until the vehicle ahead of you passes a pavement marking or some other clear landmark, then use the stopwatch on your mobile phone to see how long it takes you to reach the same spot.

5. Foundation brakes are used:

only with the right wheels.
only with the front wheels.
at each wheel.

6. You are coupling a tractor to a semi-trailer and have backed up but are not yet under the trailer. Before backing under the semi-trailer, you should hook up:

the electrical service cable.
the safety chain.
the emergency and service air lines.

7. Who is responsible for inspecting the cargo?

The shipper
The driver
The person who loaded and secured the cargo

8. When backing a trailer, if you turn the wheel left:

the cab and the trailer will go left.
the cab will go right and the trailer will go left.
the cab will go left and the trailer will go right.

9. Which of the following is NOT part of checking the sliding fifth-wheel?

Checking that all locking pins are present and locked in place
Checking that it is properly greased
Testing the tractor protection valve

10. When your vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called:

off-tracking.
front-rear tracking.
skidding.

Number of questions:	20
Correct answers to pass:	16
Passing score:	80%

COMBINATION TEST IDAHO - PRACTICE TEST

ID CDL Combination Test