COMBINATION PRACTICE TEST - SC CDL

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Drivers who want to drive combination vehicles must pass the combination vehicles test. The South Carolina 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 South Carolina CDL Manual. Take this practice test now to prepare for the actual SC CDL combination test!
1. As part of your vehicle inspection, you are checking that air flows to all trailers. After using the trailer handbrake to provide air to the service line, you go to the rear of the rig. When you open the emergency line shut-off valve at the rear of the last trailer, you should hear:
a mechanical vibration.
air escaping from the open valve.
the service line valve close.
a thumping sound.
2. An Anti-lock Braking System (ABS):
always shortens your stopping distance.
lets you drive faster.
keeps your wheels from locking up when you brake hard.
increases your normal braking capability.
3. Inspecting the fifth-wheel does NOT include:
backing until the fifth-wheel just touches the trailer.
making sure that the fifth wheel is in the proper position for coupling.
checking that there are no cracks in the frame.
checking for missing or damaged parts.
4. A steering wheel should have no more than _____ of play. If there is more play than this, it may be hard to steer.
15 degrees
10 degrees
30 degrees
It doesn't matter.
5. Hanging meat in a refrigerated truck can be:
a very unstable load with a high center of gravity.
a very unstable load with a low center of gravity.
a very stable load with a low center of gravity.
a very stable load if properly distributed.
6. Tar in the road pavement rising to the road surface in very hot weather:
might get in your engine.
is very sticky and will slow down your vehicle.
causes the road to become very slippery.
does not affect the road surface or driving conditions.
7. When you are uncoupling a loaded trailer, lower the landing gear until:
it makes firm contact with the ground.
the tractor frame is under the trailer.
the pressure in the system is above 55 psi.
makes contact with the ground, and leave the trailer off the fifth wheel.
8. What is the emergency air line for?
It tells you the amount of brake pressure you need to stop the vehicle.
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.
All of the above.
9. Do not use the trailer hand valve in driving because:
the trailer emergency brakes will come on.
the brakes can overheat and lose their braking power.
of the danger of making the trailer skid.
All of the above.
10. "Bobtail" tractors are:
tractors with two trailers.
heavily loaded trailers.
tractors with a tank.
tractors without semitrailers.
 
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SC Combination Test

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