Class A · General Knowledge

General Knowledge practice test

20 free questions to answer on this page, each with its explanation and the manual section. The app has all 298, with exam mode and a mistakes list.

50Questions in most states
40Right to pass
80%Pass mark
Question 1 of 20
  1. Question 1 of 20 · Section 2.1

    Why is a broken exhaust system dangerous?

    Answer: B, Poisonous fumes can get into the cab

    Exhaust leaks can let poison fumes reach the cab or sleeper berth, so look for loose, broken, or leaking exhaust parts.

    General Knowledge · Section 2.1.3 · California CDL Handbook

  2. Question 2 of 20 · Section 2.2

    In a vehicle with a manual transmission, how do you avoid rolling back when you start from a stop?

    Answer: C, Partly engage the clutch before lifting your right foot off the brake

    Get the clutch partly engaged first, then lift your foot from the brake. Use the parking brake when needed so you do not roll back into someone.

    General Knowledge · Section 2.2.1 · California CDL Handbook

  3. Question 3 of 20 · Section 2.3

    Why should you know where retarder use is allowed?

    Answer: D, Retarders can be noisy

    Retarders can be loud, so make sure you know where you are permitted to use them.

    General Knowledge · Section 2.3.4 · California CDL Handbook

  4. Question 4 of 20 · Section 2.4

    A traffic light ahead has been green for a long time. What should you do?

    Answer: C, Start slowing down and be ready to stop

    A light that has been green a long time will probably change before you get there, so begin slowing down and be prepared to stop.

    General Knowledge · Section 2.4.1 · California CDL Handbook

  5. Question 5 of 20 · Section 2.5

    At dawn, at dusk, or in rain or snow, how should you make yourself easier to see?

    Answer: B, Turn on your low-beam headlights

    If you are having trouble seeing others, they will have trouble seeing you. Use your headlights, not just identification or clearance lights, on low beam.

    General Knowledge · Section 2.5.2 · California CDL Handbook

  6. Question 6 of 20 · Section 2.6

    Why is the road especially slippery just after it starts to rain?

    Answer: D, Water mixes with oil left on the road

    Early rain mixes with oil on the pavement and makes it very slippery. If the rain keeps falling, it washes the oil away.

    General Knowledge · Section 2.6.2 · California CDL Handbook

  7. Question 7 of 20 · Section 2.7

    Where can a heavily loaded vehicle get hung up because of low clearance underneath?

    Answer: B, On dirt roads and in unpaved yards

    The space under a loaded vehicle can be very small. Cross dips and drainage channels carefully, and do not risk getting stuck on railroad tracks.

    General Knowledge · Section 2.7.5 · California CDL Handbook

  8. Question 8 of 20 · Section 2.8

    Which clue tells you a parked car may be about to pull out?

    Answer: D, Brake lights, backup lights, or exhaust

    Watch for movement inside the car and for brake lights, backup lights, or exhaust that show a driver is about to move.

    General Knowledge · Section 2.8.3 · California CDL Handbook

  9. Question 9 of 20 · Section 2.9

    How can distracted driving affect you behind the wheel?

    Answer: C, It slows how fast you notice and react to events

    Distraction slows perception, so you may notice an important event late or not at all, and it delays your decisions and actions.

    General Knowledge · Section 2.9.2 · California CDL Handbook

  10. Question 10 of 20 · Section 2.11

    If your license requires corrective lenses, when must you wear them while driving?

    Answer: A, Every time you drive

    Always wear them, even for short distances, and keep a spare pair in the vehicle in case your regular lenses break or get lost.

    General Knowledge · Section 2.11.2 · California CDL Handbook

  11. Question 11 of 20 · Section 2.13

    What happens to an icy road as the temperature rises and the ice starts to melt?

    Answer: A, It becomes even more slippery

    Melting ice is wetter and slicker, so slow down even more as temperatures rise toward melting.

    General Knowledge · Section 2.13.2 · California CDL Handbook

  12. Question 12 of 20 · Section 2.15

    About how long does a typical tractor-trailer need to clear a double railroad track?

    Answer: C, More than 15 seconds

    Clearing one track takes a typical tractor-trailer at least 14 seconds, and a double track takes more than 15. Do not start across unless you can get all the way over.

    General Knowledge · Section 2.15.5 · California CDL Handbook

  13. Question 13 of 20 · Section 2.16

    When is the braking effect of the engine strongest?

    Answer: A, Near governed rpm, in low gears

    Engine braking works best when the engine is near its governed rpm and the transmission is in a low gear.

    General Knowledge · Section 2.16.1 · California CDL Handbook

  14. Question 14 of 20 · Section 2.17

    Which is a sign that a front tire has failed?

    Answer: C, The steering feels heavy

    A loud bang, heavy vibration, or steering that suddenly feels heavy are signs of tire failure.

    General Knowledge · Section 2.17.4 · California CDL Handbook

  15. Question 15 of 20 · Section 2.19

    How do you correct a drive-wheel braking skid?

    Answer: A, Stop braking, then countersteer

    Releasing the brakes lets the rear wheels roll again. As the vehicle comes back on course, turn the wheel quickly the other way so you do not skid the opposite way.

    General Knowledge · Section 2.19.2 · California CDL Handbook

  16. Question 16 of 20 · Section 2.21

    Which of these is a common electrical cause of vehicle fires?

    Answer: C, Short circuits from damaged insulation

    Short circuits from damaged insulation and loose connections can start electrical fires.

    General Knowledge · Section 2.21.1 · California CDL Handbook

  17. Question 17 of 20 · Section 2.22

    Which of these is a common effect of alcohol on driving?

    Answer: C, Straddling lanes

    Alcohol causes errors like straddling lanes, jerky starts, not signaling, running stop signs and lights, and improper passing.

    General Knowledge · Section 2.22.1 · California CDL Handbook

  18. Question 18 of 20 · Section 2.23

    What are the hazardous materials rules meant to do?

    Answer: B, Contain products and communicate risks

    The rules aim to contain the product, communicate the risk, and make sure drivers and equipment are safe.

    General Knowledge · Section 2.23.2 · California CDL Handbook

  19. Question 19 of 20 · Section 3.2

    How should heavy and light cargo be loaded to keep the center of gravity low?

    Answer: A, Put the heaviest items under the lightest ones

    A high center of gravity makes tipping over more likely, especially in a curve or a swerve. Keep the load low, with the heavy items at the bottom.

    General Knowledge · Section 3.2.3 · California CDL Handbook

  20. Question 20 of 20 · Section 3.3

    What are the two basic reasons for covering cargo?

    Answer: B, To protect people from spills and cargo from weather

    Covers protect people from spilled cargo and protect the cargo from the weather. Spill protection is a safety requirement in many states.

    General Knowledge · Section 3.3.4 · California CDL Handbook

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The full bank is in the app

All 298 General Knowledge questions, an exam mode with 50 questions and the 80% pass mark, explanations for every answer, and a mistakes list that keeps what you missed until you clear it.

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What the General Knowledge test covers

Sections 2 and 3 of the CDL manual: Driving Safely and Transporting Cargo Safely. Every CDL applicant takes this test (Section 1.1.1 in the California, Texas and Florida handbooks). The section numbers are the same in the California, Texas and Florida handbooks.

Section 2.1: Vehicle inspectionWhy inspect, types of vehicle inspections, what to look for, CDL vehicle inspection test30 questions in the app
Section 2.2: Basic control of your vehicleAccelerating, steering, stopping, backing safely8 questions in the app
Section 2.3: Shifting gearsManual transmissions, multi-speed rear axles and auxiliary transmissions, automatic transmissions, retarders9 questions in the app
Section 2.4: SeeingSeeing ahead, seeing to the sides and rear7 questions in the app
Section 2.5: CommunicatingSignal your intentions, communicating your presence11 questions in the app
Section 2.6: Controlling your speedStopping distance, matching speed to the road surface, speed and curves, speed and distance ahead26 questions in the app
Section 2.7: Managing spaceSpace ahead, space behind, space to the sides, space overhead16 questions in the app
Section 2.8: Seeing hazardsImportance of seeing hazards, hazardous roads, drivers who are hazards, always have a plan19 questions in the app
Section 2.9: Distracted drivingThe distracted driving crash problem, effects of distracted driving, types of distractions, cell/mobile phones13 questions in the app
Section 2.10: Aggressive drivers/road rageDo not be an aggressive driver, what you should do when confronted by an aggressive driver6 questions in the app
Section 2.11: Driving at nightIt is more dangerous, driver factors, roadway factors, vehicle factors18 questions in the app
Section 2.12: Driving in fog4 questions in the app
Section 2.13: Driving in winterVehicle checks, driving on slippery surfaces12 questions in the app
Section 2.14: Driving in very hot weatherVehicle checks, driving in the heat6 questions in the app
Section 2.15: Railroad-highway crossingsTypes of crossings, warning signs and devices, driving procedures, stopping safely at railroad-highway crossings11 questions in the app
Section 2.16: Mountain drivingSelect a “safe” speed, select the right gear before starting down the grade, brake fading or failure, proper braking technique7 questions in the app
Section 2.17: Driving emergenciesSteering to avoid an accident, how to stop quickly and safely, brake failure, tire failure15 questions in the app
Section 2.18: Anti-lock braking systems (ABS)How anti-lock braking systems work, vehicles required to have ABS, how to know if your vehicle is equipped with ABS, how ABS helps you7 questions in the app
Section 2.19: Skid control and recoveryDrive-wheel skids, correcting a drive-wheel braking skid, front-wheel skids8 questions in the app
Section 2.20: Accident proceduresProtect the area, notify authorities, care for the injured, gather information6 questions in the app
Section 2.21: FiresCauses of fire, fire prevention, fire fighting12 questions in the app
Section 2.22: Alcohol, other drugs, and drivingAlcohol and driving, other drugs, illness10 questions in the app
Section 2.23: Hazardous materials rules for all commercial driversWhat are hazardous materials, why are there rules, lists of regulated products8 questions in the app
Section 3: Transporting cargo safely: introduction2 questions in the app
Section 3.1: Inspecting cargo2 questions in the app
Section 3.2: Cargo weight and balanceDefinitions you should know, legal weight limits, do not be top-heavy, balance the weight13 questions in the app
Section 3.3: Securing cargoBlocking and bracing, cargo tie-down, header boards, covering cargo8 questions in the app
Section 3.4: Cargo needing special attentionDry bulk, hanging meat, livestock, oversized loads4 questions in the app