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Safely pulling double and triple trailers requires knowledge and skill. If you want to pull double or triple trailers, you must add the Doubles/Triples (T) endorsement to your Class A CDL. The Idaho doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The ID CDL doubles triples test covers the following sections of the Idaho CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this ID CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Idaho.
1. 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.
2. You are more at risk of being fatigued:
after getting more than 8 hours of sleep.
when stopping periodically during long trips.
when driving alone.
3. Air brakes use ________ to make the brakes work.
compressed gases
compressed gas cylinders
compressed air
4. If there is a cargo fire in a van or box trailer, you should:
open the doors, especially if your cargo contains hazardous materials.
enlist the help of bystanders.
keep the doors shut.
5. Air pressure should build up in a single air system, within about:
15 minutes.
3 minutes.
10 minutes.
6. Strong winds can make it difficult to stay in your lane, especially when:
coming out of tunnels.
driving at speeds below 40 mph.
going into tunnels.
7. Hydroplaning:
can occur only if there is a lot of water on the road.
is less likely if tire pressure is low.
can occur at speeds as low as 30 mph.
8. If the drive wheels start to skid:
use the brakes to slow down.
accelerate slightly to regain control.
push in the clutch to let them turn freely.
9. If you cannot make a right turn without entering another traffic lane, you should:
turn wide as you complete the turn.
turn wide before you start the turn.
swing wide to the left before starting the turn.
10. When conducting a pre-trip inspection:
the vehicle inspection report should not be reviewed unless your supervisor tells you to do so.
the inspection report should only be reviewed if you will be carrying passengers.
you should review the last vehicle inspection report.
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Doubles Triples ID CDL Test

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