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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 South Dakota doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The SD CDL doubles triples test covers the following sections of the South Dakota CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this SD CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in South Dakota.
1. After the pre-trip inspection, drivers should inspect their cargo and its securing devices again within ________ after beginning the trip.
two hours
50 miles
25 miles
20 miles
2. Drivers transporting cargo are responsible for:
inspecting the cargo.
making sure the cargo is properly secured.
recognizing overloads.
All of the above.
3. Foundation brakes are used:
only with the rear wheels.
only with the front wheels.
only with the right wheels.
at each wheel.
4. Rims with welding repairs:
can be used for tires in the rear of the vehicle.
are not safe.
can be used for tires in the front of the vehicle.
are acceptable only when carrying a heavy load.
5. When driving in extremely hot weather, if the air pressure in the tires is too high, you should:
call your supervisor.
let air out of the tires to decrease pressure.
continue driving.
stop and remain stopped until the tires cool off.
6. On any upgrade, _________ – the more you will have to use lower gears to climb hills or mountains.
the longer the grade
the steeper the grade
the heavier the load
All of the above.
7. You are driving a double. Before entering traffic, you should:
make sure you have a large enough gap before entering or crossing traffic.
assume there is enough room to merge into traffic.
always come to a complete stop.
turn on your headlights.
8. Most heavy duty vehicles use ___ air brake systems for safety.
9. When parked on the side of the road, you should:
use the 4-way emergency flashers.
activate the right turn signal.
flash your brake lights.
turn off all lights.
10. "Bobtail" tractors are:
heavily loaded trailers.
tractors with two trailers.
tractors with a tank.
tractors without semitrailers.
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SD CDL Doubles Triples Test

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