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Drivers who want to drive combination vehicles must pass the combination vehicles test. The Idaho 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 Idaho CDL Manual. Take this practice test now to prepare for the actual ID CDL combination test!
1. Where are shut-off valves?
At the back of each trailer.
At the front of each trailer.
At the front and back of each trailer.
2. Before connecting the converter dolly to the rear trailer, make sure that:
the shut-off valves at the rear of the first trailer are open.
the trailer height is slightly lower than the center of the fifth-wheel.
the kingpin rests on the fifth-wheel.
3. Which of the following is NOT TRUE? When you drive a tractor-trailer combination with ABS, you should:
drive slower to keep your vehicle in a straight line.
brake the same way, regardless of whether you have ABS on the tractor, the trailer, or both.
monitor your tractor and trailer as you slow down, and if it is safe to do so, back off the brakes to stay in control.
4. Which of the following may have reduced the clearances since the heights were posted at bridges and overpasses?
The weight of a cargo
Rain
Repaving of the road
5. When driving in a construction zone, if a construction worker is near the road, you should:
maintain a constant speed.
come to a complete stop.
further reduce your speed.
6. When checking the lights before driving:
you should check them from inside the vehicle.
make sure the parking brake is not set.
you should turn off the engine.
7. The tractor protection valve:
supplies air to the trailer air tanks.
keeps air in the tractor brake system should the trailer break away or develop a bad leak.
controls the emergency brakes on combination vehicles.
8. A red triangle with an orange center means:
Slow-moving vehicle
The vehicle is hauling hazardous materials
Law enforcement vehicle
9. In combination vehicles with air brakes, the trailer air supply control should pop out when the air pressure falls within the range of:
20 to 45 psi
100 to 120 psi
10 to 20 psi
10. If the fifth-wheel locking lever is not locked after the jaws close around the kingpin:
the parking brakes are on and your vehicle is safe to drive.
the coupling is not right and you should not drive until you get it fixed.
the parking brakes are on and the wheels are chocked.
 
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ID CDL Combination Test

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