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The CDL general knowledge test is required to be taken by all CDL applicants. The District of Columbia CDL test consists of 50 questions. To pass, you must correctly answer at least 40 questions (80%). The general knowledge test covers the contents of the District of Columbia CDL Manual. All CDL applicants (Class A, B and C) must study the following sections: Driving Safely, Transporting Cargo Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Vehicle Inspection Test, Basic Control Skills Test, Road Test. In addition, the Class A CDL test will include questions based on the Combination Vehicles section. Take this CDL practice test now to prepare for the actual DC general knowledge test! To get your CDL, you must pass both the knowledge and skills tests. CDL knowledge tests include: General Knowledge, Passenger Transport, Air Brakes, Combination Vehicles, Hazardous Materials, Tanker Vehicles, Doubles/Triples, School Bus, Firefighter. Depending on what class of license (A, B or C) and endorsements you need, you must take one or more knowledge tests. A special endorsement is also required to drive certain types of vehicles. The following endorsements may be used with a Class A, B or C CDL: HazMat (H), Tank Vehicles (N), Tank Vehicles Transporting Hazardous Materials (X) and Passenger Transport (P). The School Bus endorsement (S) is only available for Class A or B CDL, and the Doubles/Triples endorsement (T) is only available for Class A driver's licenses.
1. To avoid becoming a distracted driver you should:
not engage in complex conversations with others.
adjust all vehicle controls and mirrors while driving.
eat and drink while you drive.
not turn off all communication devices.
2. You are driving on a steep downgrade in the proper low gear. Your "safe" speed is 40 mph. When your speed reaches 40 mph, you should:
maintain your current speed, and apply the brakes when you reach 50 mph to gradually reduce your speed to 40 mph.
apply the brakes to quickly reduce your speed to 25 mph, and then release the brakes.
increase your speed to approximately 45 mph, and then apply release the brakes.
apply the brakes to gradually reduce your speed to 35 mph, and then release the brakes.
3. When you exit a highway using an off ramp that goes downhill and turns at the same time, you should:
wait until you are in the curve curved part of the off ramp before downshifting.
slow down before you get on the curved part of an off ramp.
slow down to the posted speed limit for the off ramp.
get on the curved part of the off ramp, then brake and turn at the same time.
4. Engine oil pressure should come up to normal within _________ after the engine is started.
two minutes
ten minutes
five minutes
5. On engine start, you should:
make sure the oil pressure gauge is working.
check for minimum tread depth.
check the oil level.
check that the master cylinder is securely attached and not leaking.
6. When you need to brake, you should warn the drivers behind:
by turning on the 4-way emergency flashers.
by changing lanes.
by flashing your brake lights.
by making gestures.
7. Use your four-way emergency flashers:
when stopping at railroad highway crossings.
to warn drivers behind you that people are working on the road.
when parked at the side of the road.
All of the above.
8. Sleep debt is defined as:
the accumulated amount of sleep from frequent rest brakes.
the cumulative effect of not getting enough sleep.
the amount of sleep you get each night.
All of the above.
9. If there is a sign indicating "Maximum Safe Speed", you should:
consider it as a suggestion.
never exceed the speed shown.
know that it doesn't apply to vehicles weighing more than 26,000 pounds.
travel at the posted speed.
10. The safety relief valve is located:
in the first tank the air compressor pumps air to.
on each end of the vehicle's axles.
in the front brake.
on the dashboard.
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DC CDL Knowledge Test

Number of questions: 50
Correct answers to pass:40
Passing score:80%
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