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Drivers who want to drive combination vehicles must pass the combination vehicles test. The Kentucky CDL combination test consists of 20 questions, and you'll need at least 16 correct answers to pass (80%). The test covers the combination vehicles section of the Kentucky CDL Manual. Take this practice test now to prepare for the actual KY CDL combination test!
1. How can you tell if a converter dollie has ABS?
There is a red lamp on the left side of the dolly.
There is an ABS system on the right side of the dolly.
There is a yellow lamp on the left side of the dolly.
There is an ABS plaque on the right side of the dolly.
2. Air brakes use ________ to make the brakes work.
compressed gases
compressed gas cylinders
compressed oil
compressed air
3. When approaching a vehicle with a distracted driver, you should:
quickly pass the vehicle.
maintain your safe following distance.
sound your horn.
change lanes quickly.
4. Which of the following is NOT a way to determine if your trailer is equipped with ABS (antilock braking system)?
It was built after March 1, 1998.
It has yellow ABS malfunction lamps.
Wheel speed sensor wires are coming from the back of the brakes.
The letters "ABS" are printed on the side of the steering wheel.
5. During a walk around inspection of a combination vehicle, drivers should check that:
the glide plate is securely mounted to the trailer frame.
all locking pins are present and locked in place.
the locking jaws are around the shank.
All of the above.
6. After the pre-trip inspection, drivers should inspect their cargo and its securing devices again within ________ after beginning the trip.
25 miles
two hours
50 miles
20 miles
7. In vehicles with air brakes, the tractor protection valve:
provides the air pressure used to operate trailer brakes.
keeps air in the tractor or truck brake system.
is used to connect the service and emergency air lines from the truck/tractor to the trailer.
carries air, which is controlled by the trailer hand brake or the foot brake.
8. Banked curves:
should always be avoided.
have a safe "design speed".
can be taken at any speed.
are reserved for pedestrians.
9. You are coupling a tractor to a semi-trailer. After checking the trailer height but before supplying air to the trailer, you should:
raise the front trailer supports.
connect the air lines to the trailer.
lock the trailer brakes.
inspect the fifth-wheel.
10. When going down grades, you should:
put the transmission in Neutral.
rely solely on engine braking to reduce your speed.
downshift to a lower gear.
shift up.
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KY CDL Combination Test

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