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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 Oregon doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The OR CDL doubles triples test covers the following sections of the Oregon CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this OR CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Oregon.
1. How should you apply the brakes when going down a steep downgrade?
Apply the brakes when you reach the bottom of the downgrade.
You should not brake, and only use engine braking to prevent brake failure.
Apply the brakes whenever you reach your safe speed, until your speed has been reduced to 5 mph below your safe speed.
Apply the brakes as hard as you can without locking the wheels.
2. Air tanks usually hold enough compressed air to allow the brakes to be used _________ even if the compressor stops working.
for 3 days
for one stop
several times
for one day
3. Front-end header boards:
protect drivers from spilled cargo.
should never be used.
reduce traction.
protect drivers from cargo in case of an accident or emergency stop.
4. The posted speed limit for a curve:
is optional and may be exceeded.
is safe for trucks or buses, but it may be too fast for cars.
is safe for all vehicles.
may be too fast for many trucks or buses.
5. Right after it starts to rain, the road is very slippery. Why?
Because black ice may form on the road.
Because the water mixes with oil left on the road by vehicles.
Because rain is very slippery.
None of the above.
6. Which of the following is NOT true?
ABS only comes into play when a wheel would have locked up because of over braking.
ABS will change the way you normally brake.
ABS won't compensate for poor brake maintenance.
ABS won't compensate for bad brakes.
7. The application pressure gauge:
shows how much air pressure is being applied to the brakes.
stops the compressor from pumping air.
tells you how much pressure is in the air tanks.
protects the tank and the rest of the system from too much pressure.
8. Which of the following statements about backing heavy vehicles is true?
You should avoid backing whenever you can.
Always back as quickly as possible.
The helper should stand where you cannot see the helper.
Back to the right side so that you can see better.
9. Another name for front-end header boards is:
containerized racks.
cargo stopper.
head belt.
headache racks.
10. In a dual air brake system, if one air system is very low on pressure:
either the front or rear brakes will not be operating fully.
you should pump the brakes to restore pressure.
you should drive and brake as you always have.
the effect won't be noticeable for the first 50 miles.
 
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OR CDL Doubles Triples Test

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