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Tennessee General Knowledge CDL Practice Test

Below are 25 exam-style questions for the Tennessee General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Tennessee Department of Safety and Homeland Security. 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
A controlled braking technique means:
  • A Coasting in neutral
  • B Locking the wheels
  • C Applying the brakes as hard as possible without locking the wheels
  • D Pumping the brakes hard and fast
Correct answer: C
Controlled braking applies brakes hard but stops short of wheel lock-up. With ABS, you can simply press and hold full pressure.
Question 2 of 25
A leaking exhaust system is dangerous because:
  • A It is illegal
  • B It causes the engine to overheat
  • C It can let poisonous carbon monoxide into the cab
  • D It increases fuel use
Correct answer: C
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 3 of 25
When checking the engine compartment, you should make sure that:
  • A All of the above
  • B Engine oil level is safe to operate
  • C Power steering fluid is at the proper level
  • D Coolant level is above LOW and the cap is secure
Correct answer: A
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 4 of 25
When approaching a steep downgrade, the basic safe-driving rule is:
  • A Coast in neutral
  • B Stay in high gear
  • C Select a lower gear before starting down
  • D Use the parking brake intermittently
Correct answer: C
Get into a low gear before the descent so the engine helps hold the vehicle back.
Question 5 of 25
Skids are most often caused by:
  • A Driving too fast for conditions
  • B Manual transmissions
  • C Old tires
  • D Properly working brakes
Correct answer: A
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
Engine retarders (Jake brakes) should be turned off when:
  • A On any downgrade
  • B Roads are wet, icy, or snow-covered
  • C Driving in dry conditions
  • D In residential areas only because of noise
Correct answer: B
Retarders can cause drive-wheel skids on slippery surfaces. Turn them off when traction is reduced.
Question 7 of 25
A driver who refuses to take a required drug or alcohol test is treated as if they:
  • A Took the test and failed
  • B Need to take it again later
  • C Took the test and passed
  • D Did not take the test, with no consequence
Correct answer: A
Refusal is a federal CDL disqualification with the same consequences as a positive test.
Question 8 of 25
Which is true about driving in mountains?
  • A All of the above
  • B Brakes alone are not designed to hold a heavy vehicle on a long downgrade
  • C Engine braking helps keep speed under control
  • D Heavy vehicles can slow down sharply on grades
Correct answer: A
Mountain driving combines all three. Use of low gears, engine braking, and short, moderate service-brake applications is the safe combination.
Question 9 of 25
A "wig-wag" is:
  • A A low-air pressure warning device that drops a flag in front of the driver
  • B A trailer hitch component
  • C A fuel-saving switch
  • D A type of cargo strap
Correct answer: A
On older trucks, a wig-wag is a mechanical low-air warning that lowers a flag into the driver's field of view when air pressure drops below safe limits.
Question 10 of 25
On a long downgrade, why is it dangerous to use the brakes too much?
  • A It cools the brakes too much
  • B It wastes brake pads
  • C It triggers the ABS warning light
  • D Brake fade can leave you with reduced or no braking power
Correct answer: D
Heat from continuous braking causes the friction surfaces to lose their grip. Use a low gear and brief, moderate brake applications.
Question 11 of 25
A driver may keep moving when:
  • A A vehicle is in safe operating condition
  • B Required emergency equipment is missing
  • C A trailer brake light is out
  • D A passenger door is open
Correct answer: A
Federal rules forbid driving any CMV that is not in safe operating condition. Continue only after the defect is fixed.
Question 12 of 25
Which is true about driving in rain?
  • A Roads are most slippery just after rain begins, when water mixes with road oil
  • B It is safe to drive at the posted speed limit
  • C Tire chains are required by federal law
  • D High beams improve visibility in heavy rain
Correct answer: A
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 13 of 25
The proper response to a tire blowout on the front axle is to:
  • A Hold the steering wheel firmly, ease off the accelerator, and let the vehicle slow down
  • B Shift to neutral and coast
  • C Steer sharply toward the shoulder
  • D Brake immediately and pull off the road
Correct answer: A
Hard braking after a blowout can cause loss of control. Hold the wheel, release the accelerator, and let speed bleed off before braking gently.
Question 14 of 25
The two main reasons why a driver's feet are kept off the brakes when not actively braking are:
  • A So the brake lights don't mislead following drivers and so the brakes don't overheat
  • B To rest the right leg
  • C To save fuel and improve mileage
  • D To save brake pads and reduce drag
Correct answer: A
Riding the brake lights confuses drivers behind you and gradually heats the friction surfaces, both of which are safety problems.
Question 15 of 25
When driving at night, you should adjust speed so that you can stop within:
  • A Half the range of your low-beam headlights
  • B The full range of high-beam headlights when in use
  • C The range of your low-beam headlights
  • D Whatever speed feels safe
Correct answer: C
Always be able to stop within the distance you can see. At night with low beams, that's typically about 250 feet.
Question 16 of 25
Which is true about the use of turn signals?
  • A Use the four-way flashers instead of signals at intersections
  • B Signal only when other vehicles are present
  • C Signal only at the moment you start turning
  • D Signal early, signal continuously, and cancel after the turn
Correct answer: D
The federal model manual specifies signal early, continuously, and cancel after — the same three steps every state CDL test asks about.
Question 17 of 25
Black ice is most likely on:
  • A Roads in direct sunlight
  • B Bridges and overpasses
  • C Concrete pavement only
  • D Gravel surfaces
Correct answer: B
Bridges and overpasses freeze first because cold air circulates above and below them. They are the most-asked test scenario for sudden ice.
Question 18 of 25
Acceleration must be smooth and gradual to avoid:
  • A Engine damage
  • B Powertrain wear and possible loss of control on slippery surfaces
  • C Wasting fuel only
  • D Annoying passengers
Correct answer: B
Quick throttle inputs on slick surfaces can spin the drive wheels and cause a tractor jackknife. Smooth acceleration avoids this and reduces wear.
Question 19 of 25
When should you use four-way flashers?
  • A Only on the highway
  • B Whenever you feel like it
  • C Only at night
  • D When you are stopped or moving slowly enough to be a hazard
Correct answer: D
Four-ways are for vehicles stopped on or near the road or moving so slowly that they are a hazard.
Question 20 of 25
Which of the following is NOT part of a pre-trip inspection?
  • A Checking the engine compartment
  • B Adjusting the trailer brakes individually
  • C Walking around the vehicle and checking lights
  • D Testing the service and parking brakes
Correct answer: B
Adjusting brakes is a maintenance task done by qualified personnel, not a pre-trip step. The driver checks for proper operation, not adjustment.
Question 21 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 Honk and accelerate
  • B Cover the brake and slow down
  • C Move to the right lane
  • 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 22 of 25
When backing a heavy vehicle, you should:
  • A Back fast to get it over with
  • B Use a helper and walk around the vehicle first
  • C Back without using mirrors so you can watch out the window
  • D Back to the right whenever possible
Correct answer: B
Always GOAL — Get Out And Look — and use a helper. Backing to the left when possible is preferred because you can see better, not to the right.
Question 23 of 25
The maximum allowable on-duty driving time after 8 consecutive hours off duty is:
  • A 14 hours
  • B 11 hours
  • C 10 hours
  • D 16 hours
Correct answer: B
After 10 hours off duty, a property-carrying driver may drive up to 11 hours, within a 14-hour on-duty window.
Question 24 of 25
Which of the following is a valid reason to refuse a load?
  • A All of the above
  • B The cargo is not properly secured or placarded
  • C It would make you exceed federal hours-of-service rules
  • D It would push your weight over legal limits
Correct answer: A
A driver is required by federal law to refuse loads that violate HOS, weight, or hazmat rules. The driver, not the dispatcher, is liable.
Question 25 of 25
Hours-of-service records are required to be kept by:
  • A No one
  • B The dispatcher only
  • C The driver, in the form of a logbook or electronic logging device
  • D The carrier only
Correct answer: C
Drivers are responsible for accurate hours-of-service records, kept either on paper logs or, for most carriers, on an ELD.

Study tips for the Tennessee General Knowledge exam

The General Knowledge portion of the Tennessee CDL exam is graded out of the bank of questions the Tennessee Department of Safety and Homeland Security draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Tennessee 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 Tennessee 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 Tennessee Department of Safety and Homeland Security 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 Tennessee 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 Tennessee 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 Tennessee Department of Safety and Homeland Security office.

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

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