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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 District of Columbia doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The DC CDL doubles triples test covers the following sections of the District of Columbia CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this DC CDL practice test now to prepare for the actual test!
1. The application pressure gauge:
stops the compressor from pumping air.
protects the tank and the rest of the system from too much pressure.
tells you how much pressure is in the air tanks.
shows how much air pressure is being applied to the brakes.
2. When conducting a pre-trip inspection:
the inspection report should only be reviewed if you will be carrying passengers.
the vehicle inspection report should not be reviewed unless your supervisor tells you to do so.
you should review the last vehicle inspection report.
None of the above.
3. To prevent rollover, you should:
go slowly around turns.
keep the cargo as close to the ground as possible.
drive slowly around on ramps and off ramps.
All of the above.
4. The safety valve installed in the first tank the air compressor pumps air is set to open:
if there is too little pressure.
at 30 psi.
every 15 minutes.
if there is too much pressure.
5. The ABS malfunction lamp on the instrument panel is:
6. When preparing to make a right turn, you should NOT turn wide to the left as you start the turn. Why?
It makes the turn harder.
Turning wide to the left can cause your vehicle to tilt.
A following driver may try to pass you on the left.
A following driver may try to pass you on the right.
7. If during vehicle inspection a tire is too hot to touch, you should:
remain stopped until the tire cools off.
immediately decrease air pressure.
make sure there is enough engine oil on the tires.
let air out.
8. When driving trucks with trailers, drivers should:
push the brake pedal to the floor when braking.
decrease their following distance.
avoid making sudden movements with the steering wheel.
make quick lane changes.
9. With the controlled braking method:
you use the parking brake to lock the wheels.
you apply your brakes as hard as possible without locking the wheels.
you lightly tap the brakes.
you apply your brakes all the way and release the brakes when the wheels lock up.
10. To prevent a rollover, the driver should:
pay extra attention to the coolant level.
drive on the shoulder if possible.
make quick lane changes if possible.
drive slowly around corners, on ramps, and off ramps.
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DC Doubles Triples CDL Test

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