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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 driving in extremely hot weather, if the air pressure in the tires is too high, you should:
stop and remain stopped until the tires cool off.
continue driving.
let air out of the tires to decrease pressure.
call your supervisor.
2. If a trailer does not have spring brakes, to keep the trailer from moving you should:
use wheel chocks.
park on a slight decline.
use the service brakes.
close the brake valve.
3. Rollovers happen when drivers:
stop too often.
turn too fast.
turn too slowly.
brake too hard.
4. You should test the coupling by:
pulling against the pin of the second semitrailer.
applying the parking brakes so the rig will not move.
locking the pintle hook.
disconnect the safety chains.
5. When a combination vehicle goes around a corner:
the rear wheels of the trailer will never off-track.
the front and rear wheels follow a different path.
the driver must keep the rear of your vehicle far away from the curb.
All of the above.
6. When parking a trailer without spring brakes, it is very important for safety that you use wheel chocks. Why?
You may not notice a major leak in the service line until you try to put the brakes on.
if you don't use wheel chocks, supply air will be sent to the service line instead of going to charge the trailer air tanks.
The air could leak out of the trailer air tank, releasing its emergency brakes.
None of the above.
7. Doubles:
are easier to drive than straight trucks.
require more reaction time than straight trucks.
are less likely to rollover than straight trucks.
None of the above.
8. Which of the following is not proper tie-down equipment:
Bungee cords
9. Front-end header boards:
protect drivers from cargo in case of an accident or emergency stop.
should never be used.
reduce traction.
protect drivers from spilled cargo.
10. On dry pavement, the braking distance when traveling at 55 mph is about:
216 feet.
419 feet.
61 feet.
142 feet.
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IL Doubles Triples Test

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