Delaware General Knowledge CDL Practice Test
25 realistic General Knowledge practice questions for Delaware CDL applicants. Required for: All CDL applicants (Class A, B, and C). Official test: 50 questions, 40 correct to pass.
Question 1 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 2 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 3 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 4 of 25 · Rail Crossings
When approaching a railroad crossing without flashing lights or gates, you should:
-
A.
Slow down, look, and listen for trains
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B.
Always come to a complete stop
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C.
Speed up to clear the crossing quickly
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D.
Sound horn but maintain speed
Correct answer: A.
Without active warning devices, slow down and look and listen carefully for an approaching train.
Question 5 of 25 · Emergency Equipment
Which of these is the best way to prevent fires?
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A.
Smoking only outside the cab
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B.
Pre-trip inspection that includes electrical, fuel, and exhaust systems
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C.
Carrying a large fire extinguisher
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D.
Driving slowly
Correct answer: B.
A thorough pre-trip inspection that catches electrical, fuel, and exhaust defects is the best fire prevention.
Question 6 of 25 · Inspection
What is the minimum tread depth for non-steering axle tires?
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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 7 of 25 · Inspection
The proper way to test the service brake on a vehicle is to:
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A.
Pump the pedal three times
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B.
Push the brake pedal firmly while moving about 5 mph
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C.
Put the parking brake on
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D.
Listen for air leaks
Correct answer: B.
Move the vehicle forward at about 5 mph and apply the brake firmly. The vehicle should not pull to either side.
Question 8 of 25 · Cargo
Which is correct about cargo and weight balance?
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A.
Heavy cargo should always be at the rear
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B.
Cargo should be balanced and secured to prevent shifting
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C.
Side-to-side balance does not matter
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D.
Top-heavy loads improve stability
Correct answer: B.
Cargo must be evenly balanced and well secured. Top-heavy loads increase rollover risk.
Question 9 of 25 · Vehicle Dynamics
Empty trucks:
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A.
Always stop more quickly than loaded trucks
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B.
Have less traction because there is less weight on the drive axles
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C.
Can take curves at higher speeds safely
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D.
Are not affected by wind
Correct answer: B.
Empty trucks have reduced traction on drive axles and require greater stopping distances than loaded trucks.
Question 10 of 25 · Adverse Conditions
What should you do before driving in fog?
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A.
Use high beams to see further
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B.
Slow down and use low beams and fog lights if equipped
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C.
Speed up to clear the fog area
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D.
Follow another vehicle closely
Correct answer: B.
Slow down before entering fog. Use low beams and any installed fog lights.
Question 11 of 25 · Hazard Awareness
When approaching a vehicle with a flashing amber light, you should:
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A.
Speed up to pass it
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B.
Slow down and pass with caution
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C.
Stop and wait until the light is off
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D.
Honk and continue
Correct answer: B.
Amber flashing lights indicate a hazard or slow-moving vehicle. Slow down and pass carefully.
Question 12 of 25 · Emergency Equipment
Most heavy vehicle fires are caused by:
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A.
Hot tires from low pressure or under-inflated duals
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B.
Cold weather
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C.
Engine cooling system
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D.
Exhaust pipes only
Correct answer: A.
Hot tires and brakes are leading causes. Inspect tires and brakes regularly to prevent fires.
Question 13 of 25 · CDL Rules
Drivers convicted of driving a CMV without a valid CDL face:
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A.
No fines for the first offense
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B.
Civil penalties up to $5,000 and possible jail time
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C.
Only a warning
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D.
A 30-day driving restriction
Correct answer: B.
Driving without a valid CDL can lead to significant federal civil penalties and possible criminal penalties.
Question 14 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 15 of 25 · Backing
The most important hand signal you and a helper should agree on is:
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A.
Speed up
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B.
Stop
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C.
Turn left
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D.
Back straight
Correct answer: B.
Always agree on a clear stop signal before backing. The helper must be able to stop you instantly.
Question 16 of 25 · Mountain Driving
What may happen if you don't shift gears properly when going up a hill?
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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 17 of 25 · Driver Wellness
You should not eat or drink while driving because:
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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 18 of 25 · Driver Wellness
Which of these statements about staying alert to drive is true?
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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
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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 19 of 25 · Inspection
Mirror adjustment should be checked:
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A.
Only at the start of the trip
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B.
Only when something seems wrong
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C.
Prior to the start of any trip and can only be checked accurately when the trailer(s) are straight
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D.
Once per week
Correct answer: C.
Adjust and check mirrors before each trip while the trailers are straight.
Question 20 of 25 · Adverse Conditions
Black ice is:
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A.
A thick layer of ice that is easily seen
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B.
A thin layer that looks wet pavement
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C.
Only found in the far north
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D.
Not a real road hazard
Correct answer: B.
Black ice is a thin, transparent layer that looks like wet pavement. It is extremely dangerous.
Question 21 of 25 · Basic Control
Where should the wheel chocks be placed?
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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 22 of 25 · Testing
The road test will be scored on:
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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.
Question 23 of 25 · CDL Rules
What is the legal blood alcohol concentration (BAC) limit for CDL drivers?
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A.
0.08%
-
B.
0.05%
-
C.
0.04%
-
D.
0.02%
Correct answer: C.
Federal CDL law sets the BAC limit at 0.04%, half the limit for non-commercial drivers.
Question 24 of 25 · Basic Control
You should use the parking brake:
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A.
Only when parking on hills
-
B.
Whenever you leave the vehicle
-
C.
Only when leaving the engine running
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D.
Only on slick surfaces
Correct answer: B.
Always set the parking brake whenever you leave your vehicle, regardless of the surface or grade.
Question 25 of 25 · Night Driving
When meeting an oncoming vehicle at night, you should:
-
A.
Look directly at the headlights
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B.
Look toward the right side of the road
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C.
Switch to high beams
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D.
Increase speed
Correct answer: B.
Look toward the right side of the road to avoid being blinded by oncoming headlights.
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 Delaware Division of Motor Vehicles administers this knowledge test as part of its commercial driver license program. To earn the CDL General Knowledge on your Delaware CDL, you need to score at least 40 out of 50 on the official version.
Topics covered on this practice test
- Inspection: 4 questions
- Adverse Conditions: 3 questions
- Emergency Equipment: 2 questions
- CDL Rules: 2 questions
- Driver Wellness: 2 questions
- Basic Control: 2 questions
- Speed Management: 1 question
- Communication: 1 question
- Rail Crossings: 1 question
- Cargo: 1 question
- Vehicle Dynamics: 1 question
- Hazard Awareness: 1 question
- Backing: 1 question
- Mountain Driving: 1 question
- Testing: 1 question
- Night Driving: 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 Delaware 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 Delaware