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Drivers who want to drive combination vehicles must pass the combination vehicles test. The Louisiana 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 Louisiana CDL Manual. Take this practice test now to prepare for the actual LA CDL combination test!
1. Empty trucks require _____ stopping distances because empty vehicles have ______ traction.
less; more
greater; more
less; less
greater; less
2. Which of these is more likely to rollover due to the "crack-the-whip" effect?
The last trailer of triples
5-axle tractor semitrailers
The front trailer of 65 ft. conventional doubles
The last trailer of doubles
3. What is countersteering?
Staying off the brake while steering to the right to avoid an accident.
Driving too fast for conditions.
Turning the steering wheel quickly the other way after steering in an emergency situation.
Locking your wheels while turning in an emergency situation.
4. Which of the following is most likely to roll over?
The rear trailer of a double
The middle trailer of a triple
The front trailer of a double
The rear trailer of a triple
5. What is the emergency air line for?
It controls the front brakes of the tractor in case of an emergency.
It supplies air to the trailer air tanks, and controls the emergency brakes on combination vehicles.
It tells you the amount of brake pressure you need to stop the vehicle.
All of the above.
6. A bridge formula permits less maximum axle weight for axles that:
are further apart than normal
are closer together
have poor weight balance
have a high center of gravity
7. When backing with a trailer, you should:
look at your line of travel before you begin backing.
check your mirrors on both sides frequently.
make pull-ups to re-position your vehicle as needed.
All of the above.
8. If you smell exhaust fumes in the cab, you should:
remember to conduct a post-trip inspection.
stop immediately.
wait for the next stop, then inspect your vehicle.
open the windows.
9. The heavier the vehicle:
the higher the center of gravity will be.
the less work the brakes must do to stop it.
the more work the brakes must do to stop it.
None of the above.
10. If your vehicle is equipped with air brakes, loss of air pressure in the emergency line causes:
the trailer emergency brakes to come on.
the trailer spring brakes to come on.
the speed of your vehicle to increase.
All of the above.
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LA CDL Combination Test

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