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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. If you hear a loud loud "bang" and the steering feels "heavy", you should:
brake hard and pull off the road.
check your rearview mirrors to see if you have a flat tire.
hold the steering wheel firmly and stay off the brake.
pump the brakes until the vehicle has slowed down.
2. When the wheels of a trailer lock up:
the trailer will tend to swing around.
the vehicle will gradually come to a complete stop.
ABS will increase stopping power.
All of the above.
3. Which of the following is not a sign of fatigue?
Frequent blinking
Rubbing eyes
Yawning repeatedly
Keeping a steady speed
4. The posted speed limit for a curve:
is safe for trucks or buses, but it may be too fast for cars.
is optional and may be exceeded.
is safe for all vehicles.
may be too fast for many trucks or buses.
5. With low beams, drivers can see ahead about:
15 feet
250 feet
150 feet
100 feet
6. In a dual air brake system, if one air system is very low on pressure:
you should pump the brakes to restore pressure.
you should drive and brake as you always have.
either the front or rear brakes will not be operating fully.
the effect won't be noticeable for the first 50 miles.
7. When your vehicle starts to skid, you must take action to:
restore traction to the tires.
accelerate and countersteer.
use controlled braking.
use stab braking.
8. Air tanks usually hold enough compressed air to allow the brakes to be used _________ even if the compressor stops working.
for one day
for one stop
for 3 days
several times
9. Doubles and triples are:
more stable than straight trucks.
less likely to turn over than other combination vehicles.
easier to drive than other combination vehicles.
more likely to turn over than other combination vehicles because of the "crack-the-whip" effect.
10. The tire load for each tire is stated:
on the side of the tire.
on the inside of the tire.
on the vehicle's operator manual.
on the tread of the tire.
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IL CDL Doubles Triples Test

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