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Alabama CDL Class B Practice Test – 20 Questions with Answers

Prepare for the Alabama CDL Class B knowledge test with 20 practice questions covering vehicle inspection, air brakes, passenger vehicles, straight trucks, safe driving, cargo, stopping distance, and other essential commercial driving topics.

20
Questions
15 min
Time limit
Medium
Difficulty

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  1. 1. What type of vehicle can generally be operated with a Class B CDL?

    • A. A single vehicle with a GVWR of 26,001 pounds or more
    • B. Only motorcycles
    • C. Only passenger cars
    • D. Any vehicle regardless of weight
    Show answer

    A. A single vehicle with a GVWR of 26,001 pounds or more

    A Class B CDL generally applies to a single vehicle with a GVWR of 26,001 pounds or more, subject to applicable vehicle and endorsement requirements.

  2. 2. What is the primary purpose of a pre-trip inspection?

    • A. To improve fuel economy
    • B. To identify safety defects before operating the vehicle
    • C. To increase the vehicle's speed
    • D. To reduce the vehicle's weight
    Show answer

    B. To identify safety defects before operating the vehicle

    A pre-trip inspection helps identify defective or unsafe equipment before the vehicle is driven.

  3. 3. During a pre-trip inspection, what should you check on the tires?

    • A. Only the tire brand
    • B. Inflation, condition, tread, and visible damage
    • C. Only the tire color
    • D. Only the age printed on the tire
    Show answer

    B. Inflation, condition, tread, and visible damage

    Commercial drivers should inspect tires for proper inflation, adequate tread, damage, and other unsafe conditions.

  4. 4. What is the main purpose of an air compressor in an air brake system?

    • A. To store fuel
    • B. To generate compressed air for the brake system
    • C. To cool the engine
    • D. To control the steering wheel
    Show answer

    B. To generate compressed air for the brake system

    The air compressor produces compressed air and supplies it to the air reservoirs used by the braking system.

  5. 5. What does the low-air-pressure warning indicate?

    • A. The fuel level is low
    • B. Air pressure in the brake system is dangerously low
    • C. The engine oil is too cold
    • D. The tires are overinflated
    Show answer

    B. Air pressure in the brake system is dangerously low

    The low-air warning alerts the driver when air pressure has fallen to a potentially dangerous level.

  6. 6. What should you do if the low-air-pressure warning comes on while driving?

    • A. Ignore it if the vehicle is still moving
    • B. Accelerate to increase air pressure
    • C. Safely stop and address the problem
    • D. Turn off the warning system
    Show answer

    C. Safely stop and address the problem

    A low-air warning can indicate a serious brake-system problem and should not be ignored.

  7. 7. Why does a heavily loaded commercial vehicle generally require more stopping distance?

    • A. It has less momentum
    • B. Its greater weight requires more distance to stop
    • C. Its headlights are brighter
    • D. Its steering wheel is larger
    Show answer

    B. Its greater weight requires more distance to stop

    A heavier vehicle has greater momentum and generally needs more distance to stop safely.

  8. 8. What should you do when approaching a sharp turn in a large commercial vehicle?

    • A. Increase speed before the turn
    • B. Reduce speed before entering the turn
    • C. Brake hard halfway through the turn
    • D. Accelerate throughout the turn
    Show answer

    B. Reduce speed before entering the turn

    Reducing speed before a turn helps maintain control and reduces the risk of rollover or loss of traction.

  9. 9. What is one major danger of taking a curve too fast in a high-profile commercial vehicle?

    • A. Improved stability
    • B. Increased risk of rollover
    • C. Reduced stopping distance
    • D. Better visibility
    Show answer

    B. Increased risk of rollover

    High-profile and heavily loaded vehicles can have a higher center of gravity, increasing rollover risk during fast turns.

  10. 10. What should you do before changing lanes in a commercial vehicle?

    • A. Check mirrors and blind spots and signal
    • B. Only check the rearview mirror
    • C. Change lanes without signaling if traffic is light
    • D. Move immediately if the lane appears empty
    Show answer

    A. Check mirrors and blind spots and signal

    Commercial vehicles have significant blind spots, so drivers should check mirrors and blind spots and signal before changing lanes.

  11. 11. Why should a Class B commercial driver maintain extra following distance?

    • A. The vehicle may require more time and distance to stop
    • B. It prevents all vehicles from passing
    • C. It increases engine power
    • D. It eliminates the need for brakes
    Show answer

    A. The vehicle may require more time and distance to stop

    Commercial vehicles are often heavier and require more stopping distance, especially at higher speeds or in poor conditions.

  12. 12. What should you do when driving in heavy rain?

    • A. Increase speed to get through the rain
    • B. Reduce speed and increase following distance
    • C. Follow the vehicle ahead more closely
    • D. Turn off your headlights
    Show answer

    B. Reduce speed and increase following distance

    Heavy rain can reduce visibility and traction. Slowing down and increasing following distance provides additional safety.

  13. 13. What should you do if your vehicle begins to hydroplane?

    • A. Brake hard immediately
    • B. Turn sharply
    • C. Ease off the accelerator and avoid sudden movements
    • D. Accelerate quickly
    Show answer

    C. Ease off the accelerator and avoid sudden movements

    Sudden braking, acceleration, or steering can cause loss of control. Gradually easing off the accelerator can help restore traction.

  14. 14. What should you do when approaching a railroad crossing if there is not enough room on the other side for your vehicle?

    • A. Enter the crossing and wait
    • B. Stop before the tracks
    • C. Drive onto the shoulder
    • D. Cross quickly
    Show answer

    B. Stop before the tracks

    Never enter a railroad crossing unless there is enough space to completely clear the tracks.

  15. 15. What should you do if an emergency vehicle approaches with flashing lights and a siren?

    • A. Speed up
    • B. Move to the right and stop when safe
    • C. Continue at the same speed
    • D. Stop immediately in the center of the road
    Show answer

    B. Move to the right and stop when safe

    Drivers should yield to emergency vehicles using audible and visual warning signals and move to the right and stop when safe.

  16. 16. What is the safest way to back a large commercial vehicle?

    • A. Back as quickly as possible
    • B. Use mirrors, check the area, and use a spotter when appropriate
    • C. Rely only on the backup alarm
    • D. Back without checking behind the vehicle
    Show answer

    B. Use mirrors, check the area, and use a spotter when appropriate

    Backing has significant collision risk. Drivers should inspect the area, use mirrors, and use a spotter when available and appropriate.

  17. 17. Why is proper cargo securement important on a commercial vehicle?

    • A. It prevents cargo from shifting or falling
    • B. It increases the vehicle's maximum speed
    • C. It eliminates the need for inspections
    • D. It reduces the size of the vehicle
    Show answer

    A. It prevents cargo from shifting or falling

    Proper cargo securement helps prevent cargo movement, loss, and changes in vehicle stability.

  18. 18. What can happen if cargo is loaded too high on a commercial vehicle?

    • A. The center of gravity becomes higher
    • B. The vehicle becomes more stable
    • C. The stopping distance becomes shorter
    • D. The brakes become stronger
    Show answer

    A. The center of gravity becomes higher

    A higher center of gravity can make a vehicle less stable and increase the risk of rollover.

  19. 19. If you miss your intended highway exit while driving a commercial vehicle, what should you do?

    • A. Reverse on the highway
    • B. Make a sudden U-turn
    • C. Continue to the next exit and safely reroute
    • D. Use the shoulder to return to the exit
    Show answer

    C. Continue to the next exit and safely reroute

    Missing an exit does not justify a dangerous maneuver. Continue safely and use another exit or route.

  20. 20. What is an important responsibility of a Class B CDL driver before operating the vehicle?

    • A. Ensure the vehicle is safe and comply with applicable laws and regulations
    • B. Drive at the maximum possible speed
    • C. Avoid checking the vehicle if it operated normally yesterday
    • D. Ignore minor safety defects
    Show answer

    A. Ensure the vehicle is safe and comply with applicable laws and regulations

    Commercial drivers are responsible for operating safely, completing required inspections, and complying with applicable traffic and commercial vehicle requirements.