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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. When the temperature drops:
bridges will not freeze.
bridges will freeze before the road will.
bridges usually freeze after other parts of the roadway.
2. If a load is 10 feet long, the minimum number of tie-downs required is:
2
1
3
3. When you turn suddenly, which trailer is most likely to turn over?
The front trailer
The last trailer of triples
The rear trailer of doubles
4. When you turn suddenly while pulling doubles, which trailer is most likely to turn over?
All trailers are equally likely to turn over.
The rear trailer is twice as likely to turn over as the tractor.
The front trailer is twice as likely to turn over as the tractor.
5. Engine oil pressure should come up to normal within _________ after the engine is started.
two minutes
seconds
five minutes
6. With low beams, drivers can see ahead about:
100 feet
15 feet
250 feet
7. You must have at least 4/32 inch tread depth in every major groove on front tires and at least ___ inch on other tires.
4/32
2/32
1/32
8. Combination vehicles have __ air lines.
2
1
3
9. If your brakes fail on a steep mountain downgrade, you should:
leave the road immediately.
use an escape ramp if it is available.
go right if the shoulder is clear.
10. Doubles and triples:
can't be turned suddenly.
can be stopped suddenly due to their weight.
can be turned suddently due to the low center of gravity.
 
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ID CDL Doubles Triples Test

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