District of Columbia General Knowledge CDL Practice Test
25 realistic General Knowledge practice questions for District of Columbia CDL applicants. Required for: All CDL applicants (Class A, B, and C). Official test: 50 questions, 40 correct to pass.
Question 1 of 25 · Inspection
Pre-trip inspection of the vehicle should be done in the same order each time so that you:
-
A.
Will look professional to other drivers
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B.
Will learn it well and not skip anything
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C.
Can finish faster
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D.
Pass the test more easily
Correct answer: B.
Following the same order helps prevent missed steps and builds reliable habits.
Question 2 of 25 · ABS
ABS:
-
A.
Allows you to drive faster
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B.
Lets you brake hard without losing steering control
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C.
Means you don't have to use safe driving techniques
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D.
Eliminates the need to inspect brakes
Correct answer: B.
ABS preserves steering during emergency braking but does not shorten stopping distance.
Question 3 of 25 · Mountain Driving
What may happen if you don't shift gears properly when going up a hill?
-
A.
You will use less fuel
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B.
The transmission will be damaged
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C.
You may lose control on a downgrade
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D.
Engine RPM will be too low
Correct answer: C.
Improper gear use can result in losing control of speed, especially on the way back down a hill.
Question 4 of 25 · Inspection
What is the minimum tread depth for non-steering axle tires?
-
A.
1/32 inch
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B.
2/32 inch
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C.
4/32 inch
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D.
6/32 inch
Correct answer: B.
Federal regulations require at least 2/32 inch on non-steering tires.
Question 5 of 25 · Emergency Maneuvers
What should you do if your brakes fail on a downgrade?
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A.
Pump the brakes vigorously
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B.
Look for an escape ramp or open area to slow down
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C.
Shift into neutral
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D.
Turn off the engine
Correct answer: B.
If brakes fail, look for an escape ramp or a route that will slow your vehicle without endangering others.
Question 6 of 25 · Driver Wellness
Which of these statements about staying alert to drive is true?
-
A.
Coffee will overcome fatigue
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B.
You can rely on caffeine to stay awake
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C.
There is no substitute for sleep
-
D.
Cold air will keep you alert all night
Correct answer: C.
There is no substitute for adequate rest. Caffeine and cold air provide only temporary alertness.
Question 7 of 25 · Communication
Communicating your intentions means:
-
A.
Honking before each turn
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B.
Using turn signals, brake lights, and the horn appropriately
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C.
Flashing high beams at all drivers
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D.
Hand signals only at intersections
Correct answer: B.
Use signals, brake lights, and the horn properly to communicate. Hand signals supplement them.
Question 8 of 25 · Driver Wellness
Which of the following affects alcohol absorption into the body?
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A.
Drinking on a full stomach
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B.
How fast you drink
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C.
Body weight
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D.
All of the above
Correct answer: D.
Stomach contents, drinking speed, and body weight all influence absorption.
Question 9 of 25 · Adverse Conditions
Hydroplaning is most likely to occur when:
-
A.
Tires are properly inflated
-
B.
Speed is below 30 mph
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C.
Roads are dry
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D.
Tires lose contact with the road on wet pavement
Correct answer: D.
Hydroplaning happens when water builds up between the tire and the road, causing loss of contact.
Question 10 of 25 · Basic Control
Which of these is the proper way to hold a steering wheel?
-
A.
One hand at 12 o'clock
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B.
Both hands on opposite sides of the wheel
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C.
Both hands on top
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D.
One hand at 6 o'clock
Correct answer: B.
Hold the wheel firmly with both hands placed on opposite sides for full control.
Question 11 of 25 · Backing
You should always try to park:
-
A.
So that you will have to back when leaving
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B.
So that you can pull forward when leaving
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C.
On the right shoulder of any highway
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D.
Without using the parking brake
Correct answer: B.
Park so that you can pull forward to leave. Backing should always be avoided when possible.
Question 12 of 25 · CDL Rules
What document must you have to drive a CMV in interstate commerce?
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A.
A valid CDL with applicable endorsements
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B.
A current DOT physical (Medical Examiner's Certificate)
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C.
Both a valid CDL and a current Medical Examiner's Certificate
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D.
Only a regular driver license
Correct answer: C.
Interstate CMV drivers must have a valid CDL and a current medical examiner's certificate.
Question 13 of 25 · Mountain Driving
What are two special conditions where you should downshift?
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A.
Before starting down a hill and before entering a curve
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B.
In the city and at intersections
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C.
On bridges and tunnels
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D.
Whenever traffic slows
Correct answer: A.
Downshift before going down a hill and before entering a curve to maintain control.
Question 14 of 25 · Driver Wellness
What should you do when an aggressive driver confronts you?
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A.
Make eye contact and respond
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B.
Try to escape the situation safely and avoid eye contact
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C.
Slow down to teach a lesson
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D.
Speed up and pass
Correct answer: B.
Avoid engagement, give space, do not make eye contact, and report the behavior.
Question 15 of 25 · Hours of Service
How often must a driver complete a written record of duty status?
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A.
Every 8 hours
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B.
Every 12 hours
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C.
Every 24 hours
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D.
Once a week
Correct answer: C.
A daily record of duty status (logbook) must be completed each 24-hour period.
Question 16 of 25 · Adverse Conditions
What should you do when your vehicle hydroplanes?
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A.
Brake hard immediately
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B.
Release the accelerator and push in the clutch
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C.
Steer sharply
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D.
Accelerate to regain control
Correct answer: B.
Release the accelerator and push in the clutch. Don't use the brakes — let the wheels regain traction.
Question 17 of 25 · Night Driving
You should use low beam headlights:
-
A.
Whenever you can
-
B.
Within 500 feet of an oncoming vehicle and 500 feet behind another vehicle
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C.
Only in fog
-
D.
On lighted city streets only
Correct answer: B.
Use low beams within 500 feet of oncoming traffic and when following within 500 feet of another vehicle.
Question 18 of 25 · Basic Control
Where should the wheel chocks be placed?
-
A.
Behind one tire
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B.
In front of and behind tires on the same axle
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C.
Only when on a hill
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D.
Both front and rear tires of the steer axle
Correct answer: B.
Place chocks both in front of and behind the wheels to prevent the vehicle from rolling either way.
Question 19 of 25 · Inspection
Vehicle inspection is important because:
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A.
Federal and state laws require it
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B.
Safety is at risk
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C.
Defects can save lives if found early
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D.
All of the above
Correct answer: D.
Inspections are legally required and prevent breakdowns and crashes by catching defects early.
Question 20 of 25 · Driver Wellness
You should not eat or drink while driving because:
-
A.
It is illegal in all states
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B.
Spills can distract you
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C.
You should not put both hands on the wheel
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D.
It might damage the vehicle
Correct answer: B.
Eating and drinking divert attention and create spill hazards.
Question 21 of 25 · Inspection
Excessive heat in tires can:
-
A.
Improve handling
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B.
Cause tire failure
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C.
Help fuel economy
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D.
Increase tire life
Correct answer: B.
Excessive heat causes blowouts and serious damage. Check for hot tires after driving.
Question 22 of 25 · Driver Wellness
Distracted driving includes:
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A.
Talking on a hand-held cell phone
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B.
Eating
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C.
Reading maps
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D.
All of the above
Correct answer: D.
All of these activities take attention from driving and are forms of distracted driving.
Question 23 of 25 · Speed Management
The total stopping distance of a CDL vehicle includes:
-
A.
Perception, reaction, and braking distance
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B.
Only braking distance
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C.
Following distance and brake lag
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D.
Only the distance traveled while braking
Correct answer: A.
Total stopping distance is the sum of perception distance, reaction distance, brake lag, and braking distance.
Question 24 of 25 · Adverse Conditions
When a vehicle hydroplanes, the brakes:
-
A.
Will work better than usual
-
B.
May cause the vehicle to spin
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C.
Should be applied hard
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D.
Cause the engine to stall
Correct answer: B.
Braking on a hydroplaning surface can lock wheels and cause spins. Ease off the throttle instead.
Question 25 of 25 · Testing
The road test will be scored on:
-
A.
How fast you complete the route
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B.
Vehicle inspection, basic control, and on-road driving
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C.
Whether you wear a uniform
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D.
Your appearance
Correct answer: B.
You'll be evaluated on inspection skills, basic control skills, and safe on-road driving performance.
About the General Knowledge Test
The General Knowledge test covers safe vehicle inspection, basic vehicle control, shifting gears, communicating, controlling speed, controlling distance, seeing hazards, distracted driving, aggressive drivers, communicating with other drivers, night driving, driving in fog, winter driving, hot weather driving, mountain driving, driving emergencies, anti-lock braking systems, skid recovery, accident procedures, fires, alcohol and other drugs, hazardous materials awareness, and staying alert and fit to drive. Every commercial driver in the United States must pass this test before any other CDL endorsement can be added.
The DC Department of Motor Vehicles administers this knowledge test as part of its commercial driver license program. To earn the CDL General Knowledge on your District of Columbia CDL, you need to score at least 40 out of 50 on the official version.
Topics covered on this practice test
- Driver Wellness: 5 questions
- Inspection: 4 questions
- Adverse Conditions: 3 questions
- Mountain Driving: 2 questions
- Basic Control: 2 questions
- ABS: 1 question
- Emergency Maneuvers: 1 question
- Communication: 1 question
- Backing: 1 question
- CDL Rules: 1 question
- Hours of Service: 1 question
- Night Driving: 1 question
- Speed Management: 1 question
- Testing: 1 question
How to use this practice test
- Read each question carefully. CDL questions are written precisely — small wording differences matter.
- Click "Show Answers & Explanations" only after answering every question. Don't peek mid-test.
- Read the explanation for every question, even ones you got right. The reasoning is more important than the answer.
- Repeat the test until you score 100%. The questions are deterministic per state, so you can track your improvement over multiple sessions.
- Move on to the other endorsement tests for District of Columbia until you're ready for the official exam.
Tips specific to the General Knowledge test
The General Knowledge test is the foundation of every CDL. Topics include vehicle inspection, basic control, shifting, communicating, controlling speed, controlling space, hazard perception, distracted driving, night driving, fog, winter, hot weather, mountain driving, emergencies, anti-lock brakes, skid recovery, accident procedures, fires, alcohol, hazardous materials awareness, and staying alert. Most failures come from speeding through inspection-related questions; slow down and read carefully.
Other practice tests for District of Columbia