Florida General Knowledge CDL Practice Test
25 realistic General Knowledge practice questions for Florida CDL applicants. Required for: All CDL applicants (Class A, B, and C). Official test: 50 questions, 40 correct to pass.
Question 1 of 25 · Adverse Conditions
Which of the following is true about driving in fog?
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A.
You should always drive with high beams
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B.
Avoid driving in fog if possible
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C.
Use the right edge of the road as a guide rather than the center line
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D.
Both b and c
Correct answer: D.
Avoid driving in fog when possible. If unavoidable, use low beams and the right edge as a guide.
Question 2 of 25 · Night Driving
When meeting an oncoming vehicle at night, you should:
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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.
Question 3 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 4 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 5 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 6 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 7 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 8 of 25 · Inspection
When checking the engine compartment, your vehicle should be:
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A.
Idling in neutral
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B.
On a slight incline
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C.
Parked on level ground with the parking brake set and wheels chocked
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D.
Running with the parking brake off
Correct answer: C.
Always inspect the engine compartment with the vehicle parked on level ground, parking brake set, and wheels chocked.
Question 9 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 10 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 11 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 12 of 25 · Testing
When taking the road test, you will be expected to:
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A.
Demonstrate the basic control skills only
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B.
Drive only on the highway
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C.
Show that you can perform safely in normal traffic
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D.
Drive only in residential areas
Correct answer: C.
The road test evaluates safe performance in actual traffic conditions.
Question 13 of 25 · Hazard Awareness
How can you tell if your truck or bus has a hazardous materials shipment?
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A.
It is moving slowly
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B.
Diamond-shaped placards are displayed
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C.
A flashing yellow light is on
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D.
It is following another truck
Correct answer: B.
Diamond-shaped placards on the vehicle indicate the presence of hazardous materials.
Question 14 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 15 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 16 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 17 of 25 · Communication
When changing lanes you should:
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A.
Do it quickly so other drivers don't catch up
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B.
Signal early and check mirrors before and during the lane change
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C.
Turn off the radio
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D.
Speed up first
Correct answer: B.
Signal early, check mirrors, and look for traffic before and during the change.
Question 18 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 19 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 20 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 21 of 25 · Emergency Maneuvers
Stab braking is used:
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A.
Only on slippery roads
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B.
When you must stop quickly with non-ABS brakes
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C.
Whenever you stop
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D.
Only on downgrades
Correct answer: B.
Stab braking is an emergency technique used with non-ABS brakes: apply brakes fully, release when wheels lock, then reapply.
Question 22 of 25 · Communication
When should you check your mirrors?
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A.
Only before changing lanes
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B.
Frequently, to know what is around your vehicle
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C.
When parking only
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D.
Only at intersections
Correct answer: B.
Check mirrors regularly to know what is happening around your vehicle.
Question 23 of 25 · Speed Management
Engine retarders should be turned off when:
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A.
Driving uphill
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B.
The road is wet, icy, or snow covered
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C.
Traffic is heavy
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D.
You are loaded
Correct answer: B.
Retarders can cause drive wheels to skid on slippery surfaces. Turn them off in poor traction conditions.
Question 24 of 25 · Cargo
How can you tell if your vehicle is overloaded?
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A.
It rides higher than normal
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B.
It handles differently from when properly loaded
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C.
It uses less fuel
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D.
It accelerates faster
Correct answer: B.
Overloaded vehicles handle poorly — they accelerate slower, take longer to stop, and are harder to steer.
Question 25 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.
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 Florida Department of Highway Safety and Motor Vehicles administers this knowledge test as part of its commercial driver license program. To earn the CDL General Knowledge on your Florida CDL, you need to score at least 40 out of 50 on the official version.
Topics covered on this practice test
- Speed Management: 4 questions
- Adverse Conditions: 3 questions
- Inspection: 3 questions
- Night Driving: 2 questions
- Emergency Equipment: 2 questions
- Emergency Maneuvers: 2 questions
- Hazard Awareness: 2 questions
- Communication: 2 questions
- Backing: 1 question
- Vehicle Dynamics: 1 question
- Testing: 1 question
- Driver Wellness: 1 question
- Cargo: 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 Florida 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.
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