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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 Delaware doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The DE CDL doubles triples test covers the following sections of the Delaware CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this DE CDL practice test now to prepare for the actual test!
1. Blocking and bracing are:
used to keep cargo from sliding and to prevent movement of cargo.
driving techniques used to regain control when your drive wheels start to skid.
coupling devices used to connect the service air lines from the truck or tractor to the trailer.
None of the above.
2. When parked on the side of the road, you should:
turn off all lights.
activate the right turn signal.
use the 4-way emergency flashers.
flash your brake lights.
3. You should do an after-trip inspection:
at least once a week.
after each stop.
once a month.
after each trip.
4. The tractor protection valve:
works the trailer brakes.
supplies air to the trailer air tanks.
controls the emergency brakes on combination vehicles.
keeps air in the tractor brake system should the trailer break away or develop a bad leak.
5. If during vehicle inspection a tire is too hot to touch, you should:
make sure there is enough engine oil on the tires.
immediately decrease air pressure.
remain stopped until the tire cools off.
let air out.
6. On dry pavement, the braking distance when traveling at 55 mph is about:
142 feet.
61 feet.
216 feet.
419 feet.
7. When making a turn you should:
honk your horn.
make gestures to get the attention of other drivers.
turn the signal off before entering the turn.
signal early.
8. When checking the lights before driving:
the engine must be running.
you should check them from inside the vehicle.
make sure the parking brake is not set.
you should turn off the engine.
9. You have two tie-downs on a 15 foot load. How many more tie-downs do you need to secure cargo and keep it from shifting or falling?
10. When the wheels of a trailer lock up, which of the following is most likely to occur?
The trailer will tend to swing around (trailer jackknife).
The trailer will the trailer has overturn.
The trailer will tend to push the towing vehicle sideways (tractor jackknife).
The rig will stay in a straight line but slide sideways.
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DE CDL Doubles Test

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