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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. Your mirrors should be adjusted so that:
a part of the vehicle is visible in the mirror.
no part of the vehicle is visible in the mirror.
more than half of the mirror shows the vehicle.
the rear of the vehicle is visible in the mirror.
2. After starting the engine, oil pressure should rise to a normal level:
within 6 minutes.
within 2 minutes.
within seconds.
within 3 miles.
3. Axle weight is defined as:
The maximum safe weight a tire can carry at a specified pressure
The weight transmitted to the ground by one axle or one set of axles
The weight of the trailer, including the axles
None of the above.
4. When inspecting your vehicle, before checking the engine compartment be sure that:
all tires are properly inflated.
the parking brakes are on and/or wheels chocked.
the fire extinguisher is properly charged and rated.
all lights are working.
5. When driving, do NOT:
assume that vehicles, pedestrians or bicyclists see you whenever you are about to pass them.
warn the drivers behind by flashing your brake lights if you see a hazard that will require slowing down.
try to help out other drivers by signaling when it is safe to pass.
put your turn signal on before changing lanes.
6. When driving in hot weather, drivers should inspect tires:
every 3 hours or every 75 miles.
every 2 hours or every 100 miles.
every 4 hours or every 200 miles.
every hour or every 50 miles.
7. Drivers operating CMVs must notify their employer within ______ of a conviction for any traffic violation (except parking).
3 days
7 days
30 days
14 days
8. To avoid rollbacks when you start, you should:
put on the parking brake whenever necessary.
if you have manual transmission, partly engage the clutch before you take your right foot off the brake.
release the parking brake only when you have applied enough engine power.
All of the above.
9. Enough tread is especially important in winter conditions. You need at least ________ tread depth on steering axle tires.
4/32 inch
8/32 inch
2/8 inch
6/24 inch
10. Most hydraulic brake failures occur for one of two reasons, one of which is:
loss of hydraulic pressure.
relying too much on the engine braking effect.
excessive downshifting.
driving in cold weather.
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DC CDL Knowledge Test

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