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Florida General Knowledge CDL Practice Test

Below are 25 exam-style questions for the Florida General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Florida Department of Highway Safety and Motor Vehicles. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.
Question 1 of 25
You are driving on a two-lane road and you see a driver about to pull out from a side road. You should:
  • A Move to the right lane
  • B Cover the brake and slow down
  • C Honk and accelerate
  • D Maintain speed
Correct answer: B
Anticipate the worst-case behavior. Cover the brake — keeping your foot just over it — so you can react if they pull out.
Question 2 of 25
Which is true about driving in fog?
  • A Use the four-ways while in motion at highway speed
  • B Use high-beam headlights for maximum visibility
  • C Drive faster to get out of the fog quickly
  • D Use low-beam headlights and slow down
Correct answer: D
High beams reflect off fog and reduce visibility. Slow down and use low beams or fog lamps if equipped.
Question 3 of 25
A vehicle's "no-zone" is:
  • A A federal speed restriction
  • B The fuel tank area
  • C The area in front of the steer axle
  • D The area immediately next to it where other drivers are hidden in your blind spots
Correct answer: D
No-zones are the four blind-spot areas (front, rear, and both sides) where smaller vehicles are difficult or impossible to see in your mirrors.
Question 4 of 25
Engine retarders (Jake brakes) should be turned off when:
  • A On any downgrade
  • B Driving in dry conditions
  • C Roads are wet, icy, or snow-covered
  • D In residential areas only because of noise
Correct answer: C
Retarders can cause drive-wheel skids on slippery surfaces. Turn them off when traction is reduced.
Question 5 of 25
Skids are most often caused by:
  • A Properly working brakes
  • B Old tires
  • C Driving too fast for conditions
  • D Manual transmissions
Correct answer: C
The dominant cause of skids identified by the FMCSA is driving too fast for the road or weather. Sudden steering, hard braking, or hard acceleration usually triggers them.
Question 6 of 25
A leaking exhaust system is dangerous because:
  • A It increases fuel use
  • B It is illegal
  • C It causes the engine to overheat
  • D It can let poisonous carbon monoxide into the cab
Correct answer: D
Carbon monoxide from a leaking exhaust can cause headaches, drowsiness, and unconsciousness. The illegality is real but the safety risk is the bigger answer.
Question 7 of 25
When approaching a steep downgrade, the basic safe-driving rule is:
  • A Coast in neutral
  • B Use the parking brake intermittently
  • C Stay in high gear
  • D Select a lower gear before starting down
Correct answer: D
Get into a low gear before the descent so the engine helps hold the vehicle back.
Question 8 of 25
A driver who has lost the ability to safely brake the vehicle on a downgrade should:
  • A Look for an escape ramp
  • B Coast in neutral
  • C Use the parking brake hard
  • D Shift into reverse
Correct answer: A
Long downgrades have escape ramps for runaway trucks. Use them. Coasting in neutral is illegal in many states and worsens the problem.
Question 9 of 25
A driver should test the parking brake by:
  • A Driving over a speed bump
  • B Releasing the parking brake on a flat surface and tugging gently against it
  • C Pumping the brakes
  • D Setting the parking brake, releasing the service brakes, and gently trying to move the vehicle in low gear
Correct answer: D
The standard test: set parking brakes, gently apply throttle in low gear; if the vehicle moves, the parking brake is not holding.
Question 10 of 25
GCWR stands for:
  • A General Carrier Weight Rating
  • B Gross Combination Weight Rating
  • C Government Combination Weight Reading
  • D Gross Cargo Weight Rating
Correct answer: B
GCWR is the maximum allowable weight of a power unit plus a towed unit, including all cargo. It determines whether a license is Class A.
Question 11 of 25
The minimum tread depth for steer-axle tires is:
  • A 2/32 inch
  • B 1/32 inch
  • C 4/32 inch
  • D 6/32 inch
Correct answer: C
Steer tires must have at least 4/32 inch in every major groove. Other tires require at least 2/32 inch.
Question 12 of 25
When the road is slippery, you should:
  • A All of the above
  • B Increase following distance
  • C Slow down
  • D Make smooth steering and braking inputs
Correct answer: A
Slippery roads require all three: more cushion, smoother inputs, and lower speed.
Question 13 of 25
Which is true about driving in rain?
  • A High beams improve visibility in heavy rain
  • B Roads are most slippery just after rain begins, when water mixes with road oil
  • C Tire chains are required by federal law
  • D It is safe to drive at the posted speed limit
Correct answer: B
The first few minutes of rain mix with oil and grime on the road and create the slipperiest conditions. Slow down and increase following distance.
Question 14 of 25
Drivers may not drive after being on duty:
  • A 20 hours in a 24-hour period
  • B 8 hours in any 24-hour period
  • C 15 hours of driving
  • D 14 consecutive hours since coming on duty
Correct answer: D
The 14-hour rule limits the on-duty window during which up to 11 hours of driving may occur.
Question 15 of 25
When checking the engine compartment, you should make sure that:
  • A Engine oil level is safe to operate
  • B All of the above
  • C Power steering fluid is at the proper level
  • D Coolant level is above LOW and the cap is secure
Correct answer: B
A proper engine-compartment check covers oil, coolant, power steering fluid, windshield washer fluid, hoses, belts, and electrical wiring. Skipping any one of them defeats the purpose of the inspection.
Question 16 of 25
A driver's blood-alcohol concentration (BAC) of 0.04% or higher while operating a commercial motor vehicle is:
  • A Allowed if the driver feels fine
  • B Considered driving under the influence for CDL purposes
  • C A traffic violation, but not a CDL disqualification
  • D Allowed off-duty only
Correct answer: B
Federal rules treat 0.04% BAC in a CMV as DUI for CDL purposes — half the typical 0.08% limit for non-commercial drivers.
Question 17 of 25
A CDL is required to operate a single vehicle with a GVWR of:
  • A 26,001 lbs or more
  • B 20,000 lbs or more
  • C 40,000 lbs or more
  • D 10,001 lbs or more
Correct answer: A
Single vehicles at or above 26,001 lbs GVWR (Class B) require a CDL. Class A applies to combinations at or above 26,001 lbs GCWR with a trailer over 10,000 lbs.
Question 18 of 25
You may not drive a CMV with a blood-alcohol concentration of:
  • A 0.04% or higher
  • B 0.10% or higher
  • C Any detectable amount above 0.00%
  • D 0.08% or higher
Correct answer: A
0.04% is the regulatory limit for CMV operation. A detectable amount under that triggers an out-of-service order but is not necessarily a DUI conviction.
Question 19 of 25
Which is true about brake lining wear and adjustment?
  • A Brake adjustment is the dispatcher's responsibility
  • B Brakes self-adjust forever
  • C Drum brakes never need adjustment
  • D Slack adjusters need periodic checking; pushrod travel beyond limits is out-of-service
Correct answer: D
Slack adjusters can fail, and pushrod travel must be within limits. Drivers check; adjustment itself is a maintenance task for qualified personnel.
Question 20 of 25
The maximum allowable on-duty driving time after 8 consecutive hours off duty is:
  • A 11 hours
  • B 10 hours
  • C 16 hours
  • D 14 hours
Correct answer: A
After 10 hours off duty, a property-carrying driver may drive up to 11 hours, within a 14-hour on-duty window.
Question 21 of 25
Hours-of-service records are required to be kept by:
  • A The driver, in the form of a logbook or electronic logging device
  • B No one
  • C The dispatcher only
  • D The carrier only
Correct answer: A
Drivers are responsible for accurate hours-of-service records, kept either on paper logs or, for most carriers, on an ELD.
Question 22 of 25
Which of the following is a sign of fatigue?
  • A All of the above
  • B Trouble remembering the last few miles
  • C Drifting in your lane
  • D Frequent yawning
Correct answer: A
All three are classic fatigue indicators in the FMCSA model. Cold air, music, and caffeine are not effective fixes — only sleep is.
Question 23 of 25
Which is true about driving in mountains?
  • A Engine braking helps keep speed under control
  • B Brakes alone are not designed to hold a heavy vehicle on a long downgrade
  • C All of the above
  • D Heavy vehicles can slow down sharply on grades
Correct answer: C
Mountain driving combines all three. Use of low gears, engine braking, and short, moderate service-brake applications is the safe combination.
Question 24 of 25
Hydroplaning is most likely when:
  • A Tires lose contact with the road on a film of water
  • B Roads are dry but hot
  • C You brake hard on dry pavement
  • D Tires are over-inflated
Correct answer: A
Hydroplaning happens when tires ride on top of standing water at speed. Reduce risk by slowing down, keeping tires properly inflated and tread depth adequate.
Question 25 of 25
Stopping distance is made up of:
  • A Perception distance + reaction distance + brake-lag distance + braking distance
  • B Reaction distance only
  • C Brake-lag distance only
  • D Speed times weight
Correct answer: A
Total stopping distance has four parts. Air brakes add a brake-lag distance not present in hydraulic systems.

Study tips for the Florida General Knowledge exam

The General Knowledge portion of the Florida CDL exam is graded out of the bank of questions the Florida Department of Highway Safety and Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Florida CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.

Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official Florida handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.

Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about General Knowledge.

Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The Florida Department of Highway Safety and Motor Vehicles will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.

Finally, keep your General Knowledge fundamentals sharp even when you're focused on the General Knowledge exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh Florida General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the General Knowledge study guide and the matching chapter in the official Florida CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local Florida Department of Highway Safety and Motor Vehicles office.

Already comfortable with this endorsement? Drill another: FL Air Brakes · FL Combination Vehicles · FL Hazardous Materials · FL Passenger · FL School Bus · FL Tank Vehicle · FL Doubles / Triples

New to the CDL process in Florida? Read How to apply for a CDL in Florida for the document checklist and step-by-step timeline.