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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 Illinois doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The IL CDL doubles triples test covers the following sections of the Illinois CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this IL CDL practice test now to prepare for the actual test!
1. When you turn suddenly while pulling doubles, which trailer is most likely to turn over?
The front trailer is twice as likely to turn over as the tractor.
All trailers are equally likely to turn over.
The rear trailer is twice as likely to turn over as the tractor.
None of the above.
2. When checking the engine compartment in a vehicle inspection, you should check all of the following except:
Coolant level in radiator
Engine oil level
Shock absorbers
Windshield washer fluid level
3. If the fifth-wheel locking lever is not locked after the jaws close around the kingpin:
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.
the parking brakes are on and your vehicle is safe to drive.
cargo is properly blocked.
4. After starting the engine, the ABS light stays on. This means:
the ABS oil level is not adequate.
the ABS is in Neutral.
the ABS is working properly.
the ABS is not working properly.
5. If you are caught in strong winds, you should:
speed up while keeping a strong grip on the steering wheel.
immediately take your foot off the accelerator.
keep a strong grip on the steering wheel and slow down or pull off the roadway.
None of the above.
6. If your ABS malfunctions:
the parking brakes will not work.
the service brake will not work.
you still have normal brake functions.
you should immediately come to a complete stop.
7. After the pre-trip inspection, drivers should inspect their cargo and its securing devices again within ________ after beginning the trip.
25 miles
two hours
20 miles
50 miles
8. Because of the "crack-the-whip" effect, doubles and triples:
can go much faster than other combination vehicles.
are more likely to run out of gas than other combination vehicles.
are much slower than other combination vehicles.
are more likely to turn over than other combination vehicles.
9. Glad hands are:
electronic devices.
securement devices.
coupling devices.
warning devices.
10. When inspecting the coupling, how much space should there be between the upper and the lower fifth-wheel?
½ inch
It depends on the load
It depends on the trailer
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Doubles Triples IL CDL Test

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