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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 Indiana doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The IN CDL doubles triples test covers the following sections of the Indiana CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this IN CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Indiana.
1. Which of the following statements about backing heavy vehicles is true?
The helper should stand where you cannot see the helper.
Back to the right side so that you can see better.
Always back as quickly as possible.
You should avoid backing whenever you can.
2. When your vehicle starts to skid, you must take action to:
restore traction to the tires.
use stab braking.
use controlled braking.
accelerate and countersteer.
3. How does ABS help you?
ABS makes stab braking more effective.
ABS helps you avoid wheel lock up and maintain control when you brake hard on slippery surfaces.
ABS always shortens your stopping distance.
ABS replaces your normal brakes and helps you  to stop faster.
4. Skids caused by acceleration can usually be stopped by:
taking the foot off the accelerator.
applying the brakes firmly.
speeding up.
coming to a complete stop.
5. To know how much space you should keep in front of you when driving at speeds below 40 mph, one good rule says you need at least ______ for each ______ of vehicle length.
1 second; 10 feet
3 seconds; 50 feet
1 second; 5 feet
2 seconds; 10 feet
6. To prevent rollover, you should:
drive in the left lane.
turn the engine off while turning.
drive on the shoulder of the road when possible.
drive slowly around corners.
7. Which of these is more likely to rollover due to the "crack-the-whip" effect?
The last trailer of triples
The last trailer of doubles
The front trailer of 65 ft. conventional doubles
5-axle tractor semitrailers
8. When should you turn the retarder off?
when your vehicle has a high center of gravity.
when the cargo is heavy.
when the cargo is prone to shifting.
when the road is slippery.
9. ABS:
may cause your wheels to lock when you break hard.
improves your visibility at night.
helps you avoid skids caused by over braking.
helps you stop faster.
10. The weight of a truck:
has no effect on stopping distance.
has an impact on stopping distance.
is not as important as the vehicle's center of gravity in determining stopping distance.
None of the above.
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IN Doubles Triples Test

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