Pennsylvania General Knowledge CDL Practice Test
25 realistic General Knowledge practice questions for Pennsylvania CDL applicants. Required for: All CDL applicants (Class A, B, and C). Official test: 50 questions, 40 correct to pass.
Question 1 of 25 · Emergency Equipment
What three kinds of emergency equipment must you have in your vehicle?
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A.
Spare tire, fuses, and reflective triangles
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B.
Fire extinguisher, spare fuses (if equipped), and warning devices
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C.
First aid kit, water, and flares
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D.
Tool kit, fuel can, and flag
Correct answer: B.
You must have a fire extinguisher, spare electrical fuses (if equipped), and warning devices for stopped vehicles.
Question 2 of 25 · Night Driving
Which of these is true about driving at night?
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A.
You can see further than during the day
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B.
Your reaction time is faster at night
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C.
You should reduce your speed
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D.
High beams should always be used
Correct answer: C.
You see less and farther obstacles appear later at night. Slow down so you can stop within the area lit by your headlights.
Question 3 of 25 · Speed Management
When you double your speed, your stopping distance is multiplied by approximately:
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A.
Two
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B.
Three
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C.
Four
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D.
Six
Correct answer: C.
Stopping distance grows with the square of speed. Doubling speed roughly quadruples the distance needed to stop.
Question 4 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 5 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 6 of 25 · Speed Management
You are driving a vehicle that could safely be driven at 55 mph on an open highway. The traffic is heavy and moving at 35 mph. The safest speed for your vehicle in this traffic is most likely:
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A.
25 mph
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B.
35 mph
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C.
45 mph
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D.
55 mph
Correct answer: B.
You should generally adjust to the speed of surrounding traffic when it is safe to do so.
Question 7 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 8 of 25 · Speed Management
Whenever you double your speed, the impact in a crash is:
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A.
Doubled
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B.
The same
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C.
Four times greater
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D.
Half
Correct answer: C.
Crash energy increases with the square of speed — doubling speed quadruples crash forces.
Question 9 of 25 · Adverse Conditions
When a vehicle hydroplanes, the brakes:
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A.
Will work better than usual
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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 10 of 25 · ABS
What does ABS do?
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A.
Helps you stop faster
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B.
Prevents wheels from locking up during hard braking
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C.
Replaces engine brakes
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D.
Eliminates the need for service brakes
Correct answer: B.
Antilock braking systems prevent wheel lockup, helping you maintain steering control during hard braking.
Question 11 of 25 · Driver Wellness
Aggressive drivers should be:
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A.
Confronted
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B.
Reported and given plenty of room
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C.
Followed closely
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D.
Passed quickly without signaling
Correct answer: B.
Stay clear of aggressive drivers and report dangerous behavior to authorities.
Question 12 of 25 · Cargo
Which is true about cargo securement?
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A.
Drivers are responsible for inspecting cargo
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B.
Cargo only needs to be inspected at the start of a trip
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C.
Securement is the shipper's sole responsibility
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D.
Once strapped, cargo never needs re-checking
Correct answer: A.
Drivers must inspect cargo and its securement at the start of the trip and re-check periodically.
Question 13 of 25 · Inspection
What is the minimum tread depth for steering axle tires?
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A.
2/32 inch
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B.
4/32 inch
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C.
6/32 inch
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D.
8/32 inch
Correct answer: B.
Federal regulations require at least 4/32 inch tread depth on steering axle tires.
Question 14 of 25 · Backing
You should always try to park:
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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 15 of 25 · Inspection
When inspecting your vehicle, the engine should be:
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A.
Running with the hood open
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B.
Off, with the parking brake set, before starting checks under the hood
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C.
Idling in gear
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D.
Warm but turned off only on hills
Correct answer: B.
Set the parking brake, turn off the engine, and chock the wheels before checking under the hood.
Question 16 of 25 · ABS
ABS:
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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 17 of 25 · Emergency Maneuvers
Which of the following is a sign of tire failure?
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A.
A loud "bang" sound
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B.
Vibration or thumping
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C.
Heavy steering or fishtailing
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D.
All of the above
Correct answer: D.
A bang, vibration, heavy steering, or fishtailing can all indicate tire failure.
Question 18 of 25 · Communication
Drivers should signal their intentions at least:
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A.
Right at the moment of turning
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B.
50 feet before the turn
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C.
100 feet before the turn
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D.
In the city, no signaling needed
Correct answer: C.
Signal at least 100 feet before turning to give following drivers time to react.
Question 19 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 20 of 25 · Driver Wellness
Driving while you are tired is dangerous because:
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A.
It can cause you to take longer to react
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B.
You will be more attentive
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C.
You can drive longer between stops
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D.
You cannot get tickets while tired
Correct answer: A.
Fatigue significantly slows reaction time and impairs judgment.
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 · 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 23 of 25 · Night Driving
You should use low beam headlights:
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A.
Whenever you can
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B.
Within 500 feet of an oncoming vehicle and 500 feet behind another vehicle
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C.
Only in fog
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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 24 of 25 · Emergency Equipment
When stopped on the side of a level, straight, two-lane road, where should the three reflective triangles be placed?
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A.
10, 50, and 100 feet behind the vehicle
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B.
10, 100, and 200 feet behind the vehicle
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C.
On the front, side, and rear of the vehicle
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D.
50, 100, and 200 feet on the traffic side
Correct answer: B.
Triangles go 10, 100, and 200 feet behind the vehicle on a straight, level, two-lane road.
Question 25 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.
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 Pennsylvania Department of Transportation — Driver Services administers this knowledge test as part of its commercial driver license program. To earn the CDL General Knowledge on your Pennsylvania CDL, you need to score at least 40 out of 50 on the official version.
Topics covered on this practice test
- Emergency Equipment: 3 questions
- Speed Management: 3 questions
- Driver Wellness: 3 questions
- Inspection: 3 questions
- Night Driving: 2 questions
- Adverse Conditions: 2 questions
- ABS: 2 questions
- Mountain Driving: 1 question
- Cargo: 1 question
- Backing: 1 question
- Emergency Maneuvers: 1 question
- Communication: 1 question
- Basic Control: 1 question
- CDL Rules: 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 Pennsylvania 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 Pennsylvania