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CDL general knowledge practice test

The general knowledge test is the one every truck driver takes first. It covers safe driving, vehicle inspection, shifting, space management, hazards, and the rules behind the commercial learner's permit. The questions below come straight from the PassRig question bank, written from Section 2 of the FMCSA CDL manual.

Free general knowledge practice questions

Ten questions from the PassRig bank. Pick an answer in your head, then show the answer to read why. The full bank, timed mock exams and AI explanations live in the app.

  1. Total stopping distance is made up of which three parts?

    • Perception distance, reaction distance and braking distance
    • Reaction distance, skid distance and following distance
    • Perception distance, following distance and brake lag
    • Braking distance, signal distance and stopping time
    Show answer
    Answer: A. Perception distance, reaction distance and braking distance

    Perception distance is how far you travel while your brain recognizes a hazard, reaction distance is how far you travel before your foot hits the brake, and braking distance is how far the vehicle rolls once the brakes are applied. All three add up before the truck is stopped.

    Source: FMCSA CDL Manual, Section 2.6 (Speed and Stopping Distance)

  2. After stopping on a two-lane road, where should you place your warning triangles?

    • All three directly behind the vehicle
    • One within 10 feet behind, one about 100 feet behind, and one about 100 feet ahead
    • One 50 feet behind and two 50 feet ahead
    • One at the front bumper and two at 200 feet behind
    Show answer
    Answer: B. One within 10 feet behind, one about 100 feet behind, and one about 100 feet ahead

    On a two-way road, traffic comes from both directions, so one triangle goes about 100 feet ahead and two behind (within 10 feet, and about 100 feet). On a one-way or divided highway they go 10, 100 and 200 feet behind. Place them within 10 minutes of stopping.

    Source: FMCSA CDL Manual, Section 2.5 (Communicating: When Parked on the Side of the Road)

  3. If one-fourth or more of the leaves in any leaf spring are missing, the vehicle:

    • May be driven if the load is light
    • May be driven to the next terminal
    • Is fine as long as the other springs are good
    • Must be placed out of service
    Show answer
    Answer: D. Must be placed out of service

    Losing a quarter of the leaves in a spring puts the vehicle out of service. Any broken leaf that could touch a tire, cracked spring hangers, and leaking shock absorbers are also suspension defects.

    Source: FMCSA CDL Manual, Section 2.1.2 (Suspension System Defects)

  4. Which two things tell you when it is time to shift gears?

    • Fuel level and oil pressure
    • Air pressure and coolant temperature
    • Odometer reading and trip time
    • Engine speed (tachometer) and road speed (speedometer)
    Show answer
    Answer: D. Engine speed (tachometer) and road speed (speedometer)

    Learn the rpm range for each gear and shift up when the engine reaches the top of it. You can also learn which road speeds fit each gear and use the speedometer, or go by engine sound.

    Source: FMCSA CDL Manual, Section 2.3.1 (Knowing When to Shift Up)

  5. The average perception time for an alert driver is about:

    • 1 3/4 seconds
    • 1/4 second
    • 5 seconds
    • 10 seconds
    Show answer
    Answer: A. 1 3/4 seconds

    Perception time is how long it takes your eyes to see a hazard and your brain to recognize it. At 55 mph that 1 3/4 seconds covers about 142 feet before you even start to react.

    Source: FMCSA CDL Manual, Section 2.6.1 (Perception Distance)

  6. If there are two left-turn lanes at an intersection, which one should you use?

    • The left-hand turn lane
    • Either one, it does not matter
    • The lane closest to the median
    • The right-hand turn lane
    Show answer
    Answer: D. The right-hand turn lane

    A large vehicle may need to swing right to make the turn. Starting from the right-hand turn lane keeps you from swinging into the vehicle beside you.

    Source: FMCSA CDL Manual, Section 2.7.5 (Space for Turns: Left Turns)

  7. What is the best advice for driving in heavy fog?

    • Use your high beams so you can see farther
    • Follow the taillights of the vehicle ahead closely
    • Do not drive; pull into a safe parking area and wait for the fog to lift
    • Drive at normal speed but use the flashers
    Show answer
    Answer: C. Do not drive; pull into a safe parking area and wait for the fog to lift

    Fog can be so thick you cannot see hazards in time. If you must drive, slow down, use low beams and fog lights, be ready to stop, and never try to pass.

    Source: FMCSA CDL Manual, Section 2.12 (Driving in Fog)

  8. A 'passive' railroad crossing is one that:

    • Is closed to trucks
    • Has no traffic control device such as gates or flashing lights, so you must decide for yourself when it is safe to cross
    • Always has a crossing guard
    • Has gates that come down automatically
    Show answer
    Answer: B. Has no traffic control device such as gates or flashing lights, so you must decide for yourself when it is safe to cross

    At a passive crossing you have only signs and your own judgment. Slow down, look both ways, listen, and never assume that no train is coming.

    Source: FMCSA CDL Manual, Section 2.15.1 (Types of Crossings)

  9. You come upon a crash scene. Your first step should be to:

    • Protect the area: park away from traffic, turn on flashers, and set out warning devices
    • Drive on and report it at the next exit
    • Move the injured people to the roadside
    • Take photos for the insurance company
    Show answer
    Answer: A. Protect the area: park away from traffic, turn on flashers, and set out warning devices

    Keeping another crash from happening comes first. Get your vehicle out of the traffic lanes if you can, use your flashers, and put out reflective triangles to warn others.

    Source: FMCSA CDL Manual, Section 2.19 (Accident Procedures: Protect the Area)

  10. You start to feel drowsy while driving. The safest thing to do is:

    • Turn up the radio and keep going
    • Take a stimulant and keep driving
    • Drive faster to finish the trip sooner
    • Stop driving and take a nap, or stop for the night
    Show answer
    Answer: D. Stop driving and take a nap, or stop for the night

    Drowsy drivers often fall asleep without noticing. A short nap of even 20 minutes helps more than any trick, and it keeps you from crashing before you reach your stop.

    Source: FMCSA CDL Manual, Section 2.22.2 (While You Are Driving)

What the general knowledge test covers

  • Pre-trip vehicle inspection
  • Basic vehicle control and shifting
  • Seeing, communicating and managing space
  • Speed, stopping distance and following distance
  • Night driving, fog, winter and mountain driving
  • Hazard perception and emergency manoeuvres
  • Skid control, accidents and fires
  • Alcohol, drugs, fatigue and hours of service basics

Who needs it

Every CDL applicant, Class A, B or C. It is the first test you take for your commercial learner's permit.

The test has 50 multiple-choice questions and the passing score is 80%, so you can miss 10. Your state DMV or DOT administers it; the federal rules are on the FMCSA CDL page. Study Section 2 of the CDL manual alongside these questions.

More CDL practice tests

General Knowledge test questions

How many questions are on the CDL general knowledge test?

The general knowledge test has 50 multiple-choice questions. You need 40 correct answers, which is the 80% pass mark used in every state.

What is a passing score on the CDL general knowledge test?

80%. Miss more than 10 of the 50 questions and you retake the test. PassRig mock exams use the same 50-question count and the same 80% line.

Is the general knowledge test the same in every state?

The content is federal: every state writes its test from the same FMCSA CDL manual, so the topics and the pass mark match everywhere. Your state DMV or DOT administers it and sets its own appointment rules.

How hard is the CDL general knowledge test?

Most people who read Section 2 of the manual and run a few timed practice tests pass. The common misses are stopping distance numbers, following distance rules and inspection details, so drill those first.