The CDL (Commercial Driver’s License) General Knowledge Test is a key step for anyone looking to become a professional truck or bus driver. This test checks your understanding of basic driving skills, road safety rules and vehicle operation.
It covers topics like how to inspect your vehicle before a trip, safe driving practices in different weather conditions, and how to handle cargo securely. You’ll also need to know about traffic laws, road signs and how to manage emergencies like skids or brake failures.
To pass, focus on studying the CDL manual, which has all the information you need. Practice tests are also a great way to get familiar with the types of questions you’ll face. By combining your knowledge with good preparation, you can confidently pass the CDL General Knowledge Test and start your journey as a professional driver.
Here are 50 MCQs based on the CDL (Commercial Driver’s License) General Knowledge Test, complete with explanations:
1. What is the most important reason for doing a vehicle inspection?
A) To check the appearance of the vehicle
B) To avoid fines
C) To ensure safety
D) To check the vehicle’s mileage
Answer: C) To ensure safety
Explanation: A vehicle inspection ensures that the vehicle is safe to operate and helps identify any potential hazards or mechanical issues.
2. What should you do if your vehicle’s brakes fail?
A) Pump the brakes
B) Pull the emergency brake
C) Shift to a lower gear and use the parking brake
D) Speed up and then brake hard
Answer: C) Shift to a lower gear and use the parking brake
Explanation: If your brakes fail, shifting to a lower gear will help slow the vehicle, and the parking brake can be used to stop.
3. What is the proper way to hold the steering wheel?
A) With both hands at 9 and 3 o’clock
B) With one hand at 12 o’clock
C) With both hands at 5 and 7 o’clock
D) With both hands at 10 and 2 o’clock
Answer: D) With both hands at 10 and 2 o’clock
Explanation: Holding the steering wheel at the 10 and 2 positions provides optimal control of the vehicle.
4. When driving at night, how far ahead should you be able to see with low beam headlights?
A) 100 feet
B) 200 feet
C) 300 feet
D) 500 feet
Answer: B) 200 feet
Explanation: Low beams typically allow you to see about 200 feet ahead at night.
5. What is the purpose of a pre-trip inspection?
A) To estimate fuel costs
B) To check the engine
C) To ensure the vehicle is safe to drive
D) To inspect passengers’ belongings
Answer: C) To ensure the vehicle is safe to drive
Explanation: A pre-trip inspection helps identify any mechanical or safety issues before driving.
6. What should you do if you are involved in an accident?
A) Flee the scene
B) Immediately call your employer
C) Stop driving, prevent further damage, and call the authorities
D) Leave a note for the other driver
Answer: C) Stop driving, prevent further damage, and call the authorities
Explanation: After an accident, it’s important to stop, prevent further damage, and contact the authorities for proper assistance.
7. What can help reduce the risk of a tire blowout?
A) Driving over potholes
B) Keeping tires underinflated
C) Keeping tires properly inflated
D) Overloading the vehicle
Answer: C) Keeping tires properly inflated
Explanation: Properly inflated tires are less likely to blow out compared to over- or under-inflated tires.
8. What is the minimum tread depth required for front tires?
A) 2/32 of an inch
B) 4/32 of an inch
C) 6/32 of an inch
D) 8/32 of an inch
Answer: B) 4/32 of an inch
Explanation: The minimum legal tread depth for front tires is 4/32 of an inch to ensure proper traction.
9. How do you check if your vehicle is carrying too much weight?
A) By checking the tire pressure
B) By weighing the vehicle at a scale
C) By calculating the fuel consumption
D) By measuring the speed
Answer: B) By weighing the vehicle at a scale
Explanation: Overloading can be prevented by weighing the vehicle to ensure it stays within legal weight limits.
10. When should you inspect your cargo?
A) Before and after every trip
B) Once every week
C) Only at the start of the trip
D) After reaching the destination
Answer: A) Before and after every trip
Explanation: It’s important to inspect your cargo regularly to ensure it is properly secured and balanced.
11. How should you approach a downgrade?
A) Speed up before the downgrade
B) Shift into a higher gear
C) Shift into a lower gear before the downgrade
D) Maintain the same speed
Answer: C) Shift into a lower gear before the downgrade
Explanation: Shifting into a lower gear helps control speed and reduces the need for braking.
12. What should you do if your vehicle begins to hydroplane?
A) Brake hard
B) Turn sharply
C) Ease off the accelerator and steer straight
D) Accelerate
Answer: C) Ease off the accelerator and steer straight
Explanation: Easing off the accelerator and maintaining a steady direction helps regain control during hydroplaning.
13. What is the purpose of the emergency air brake system?
A) To prevent overheating
B) To assist in parking
C) To automatically apply the brakes if there is an air brake system failure
D) To increase speed
Answer: C) To automatically apply the brakes if there is an air brake system failure
Explanation: The emergency air brake system activates if there is a failure in the main air brake system.
14. How can you identify a distracted driver?
A) They drive slowly
B) They have quick reactions
C) They are swerving or changing lanes frequently
D) They maintain proper lane discipline
Answer: C) They are swerving or changing lanes frequently
Explanation: Distracted drivers often have poor lane control and may swerve or change lanes unpredictably.
15. Which type of fire extinguisher is used for electrical fires?
A) Water extinguisher
B) Class A extinguisher
C) Class C extinguisher
D) Foam extinguisher
Answer: C) Class C extinguisher
Explanation: Class C extinguishers are designed for electrical fires.
16. What should you do if your engine overheats?
A) Turn off the engine immediately
B) Speed up to cool the engine
C) Stop and check the coolant level
D) Keep driving at a slower speed
Answer: C) Stop and check the coolant level
Explanation: If your engine overheats, stopping and checking the coolant level helps prevent damage.
17. Which of the following is a requirement for securing cargo?
A) Use only ropes
B) Ensure that cargo does not shift during transportation
C) Load all cargo on one side
D) Secure only the top part of the cargo
Answer: B) Ensure that cargo does not shift during transportation
Explanation: Properly securing cargo prevents it from shifting, which could destabilize the vehicle.
18. What does a ‘no zone’ refer to in terms of a commercial vehicle?
A) The driver’s blind spots
B) The space around the vehicle where it is illegal to park
C) Areas with high traffic
D) The area for loading cargo
Answer: A) The driver’s blind spots
Explanation: “No zones” refer to the blind spots around a commercial vehicle where other drivers may not be visible.
19. What is the main cause of skidding?
A) Poor road conditions
B) Over-braking or over-steering
C) Low tire pressure
D) Driving too fast
Answer: B) Over-braking or over-steering
Explanation: Skidding often occurs when drivers brake too hard or steer too sharply, especially on slippery roads.
20. What should you check when inspecting your vehicle’s tires?
A) Tire color
B) Tire age
C) Tire pressure and tread depth
D) The speed rating of the tires
Answer: C) Tire pressure and tread depth
Explanation: Proper tire pressure and sufficient tread depth are critical for safety and performance.
Read More : 50 MCQs on Discount for SSC, UPSC, and Other State Exams
21. What should you do when backing a large vehicle?
A) Back up as fast as possible
B) Honk continuously
C) Use a helper and sound the horn when necessary
D) Ignore obstacles
Answer: C) Use a helper and sound the horn when necessary
Explanation: A helper can assist in avoiding obstacles and ensuring a safe backing maneuver.
Here are the remaining MCQs for the CDL General Knowledge Test:
22. What is a “Gross Combination Weight” (GCW)?
A) The weight of the cargo alone
B) The total weight of the vehicle and cargo
C) The weight of the trailer alone
D) The weight of the empty truck
Answer: B) The total weight of the vehicle and cargo
Explanation: Gross Combination Weight (GCW) refers to the total weight of the vehicle and the cargo it carries.
23. When driving on wet or slippery roads, what should you do?
A) Increase your speed
B) Maintain a safe following distance
C) Use high beams to see better
D) Use the parking brake to slow down
Answer: B) Maintain a safe following distance
Explanation: Maintaining a safe distance allows you to react quickly and avoid accidents on wet or slippery roads.
24. Which of the following is an indication that a vehicle’s brakes are overheating?
A) The brakes make a loud noise
B) The vehicle speeds up
C) The brake pedal feels spongy
D) The brakes feel weak or the pedal goes to the floor
Answer: D) The brakes feel weak or the pedal goes to the floor
Explanation: Overheated brakes may lose their effectiveness, causing the brake pedal to feel weak or go to the floor.
25. What is the most important factor when securing cargo?
A) The weight of the cargo
B) Ensuring the cargo is balanced and does not shift
C) The size of the cargo
D) The color of the cargo
Answer: B) Ensuring the cargo is balanced and does not shift
Explanation: Cargo must be properly balanced and secured to avoid shifting, which could cause an accident.
26. What is the correct method to approach a curve on a highway?
A) Speed up before the curve
B) Brake hard during the curve
C) Slow down before the curve and accelerate gently after
D) Maintain the same speed throughout
Answer: C) Slow down before the curve and accelerate gently after
Explanation: Slowing down before a curve helps maintain control and prevents skidding.
27. What is the best way to avoid fatigue while driving long distances?
A) Drinking energy drinks
B) Taking regular breaks to rest
C) Driving without stopping until you reach your destination
D) Listening to loud music to stay alert
Answer: B) Taking regular breaks to rest
Explanation: Regular rest stops are essential to prevent fatigue, which can impair driving ability.
28. When is it acceptable to use a mobile phone while driving a commercial vehicle?
A) Only if you have a hands-free device
B) Only when you are in a stationary position
C) When the vehicle is stopped for a rest break
D) It is never acceptable to use a mobile phone while driving
Answer: A) Only if you have a hands-free device
Explanation: Using a hands-free device is the safest option when answering calls while driving.
29. What does the term “dimming” refer to?
A) Reducing the visibility of other vehicles
B) Reducing the intensity of your headlights to avoid blinding other drivers
C) Turning off the headlights during the day
D) Reducing speed in low visibility conditions
Answer: B) Reducing the intensity of your headlights to avoid blinding other drivers
Explanation: Dimming your headlights at night prevents blinding other drivers while ensuring adequate visibility.
30. What should you do if you need to pass another vehicle?
A) Speed up quickly and cut in front of them
B) Wait for a safe opportunity, signal, and pass at a safe speed
C) Flash your lights to signal them to move over
D) Pass on the shoulder if the traffic is slow
Answer: B) Wait for a safe opportunity, signal, and pass at a safe speed
Explanation: Passing should only be done when it is safe to do so, using signals and appropriate speed.
31. How should you handle a vehicle with an air brake system if it loses air pressure?
A) Continue driving until you find a repair shop
B) Stop immediately and safely park the vehicle
C) Apply the brakes more forcefully
D) Pump the brake pedal to restore pressure
Answer: B) Stop immediately and safely park the vehicle
Explanation: If the air pressure is too low, stop the vehicle immediately to avoid brake failure.
32. What is the primary purpose of a truck’s exhaust brake?
A) To cool the engine
B) To assist with braking when going downhill
C) To increase the speed of the vehicle
D) To prevent overheating of the tires
Answer: B) To assist with braking when going downhill
Explanation: An exhaust brake is used to slow the vehicle when driving downhill, reducing the reliance on the foot brakes.
33. How should you react to an aggressive driver?
A) Challenge them to race
B) Ignore their behavior and drive safely
C) Flash your lights at them
D) Speed up to keep up with them
Answer: B) Ignore their behavior and drive safely
Explanation: Staying calm and driving safely is the best way to deal with aggressive drivers.
34. How should you handle a situation when a tire blows out?
A) Brake immediately
B) Steer in the direction of the blowout
C) Steer away from the blowout and gradually slow down
D) Accelerate to regain control
Answer: C) Steer away from the blowout and gradually slow down
Explanation: When a tire blows out, steer away from the side of the blowout and slow down gradually to avoid losing control.
35. What is the minimum stopping distance for a commercial vehicle traveling at 55 mph?
A) 150 feet
B) 200 feet
C) 300 feet
D) 400 feet
Answer: C) 300 feet
Explanation: A commercial vehicle traveling at 55 mph requires a minimum stopping distance of around 300 feet under ideal conditions.
36. What does “double clutching” refer to?
A) Shifting gears without using the clutch
B) Pressing the clutch twice when shifting gears
C) Using both feet to operate the clutch
D) Pressing the clutch slowly while shifting
Answer: B) Pressing the clutch twice when shifting gears
Explanation: Double clutching involves pressing the clutch twice to help shift gears smoothly, especially in older vehicles.
37. What is the primary cause of truck accidents involving a rear-end collision?
A) Overloaded trucks
B) Failure to signal
C) Tailgating and following too closely
D) Speeding
Answer: C) Tailgating and following too closely
Explanation: Following too closely can result in rear-end collisions as the driver has less time to react to sudden stops.
38. What is the correct way to handle a vehicle on a sharp curve?
A) Increase speed and turn quickly
B) Slow down before entering the curve
C) Apply the brakes firmly during the curve
D) Turn the steering wheel sharply
Answer: B) Slow down before entering the curve
Explanation: Slowing down before a sharp curve helps maintain control and prevent accidents.
39. When driving in fog, what should you do?
A) Use your high beams
B) Drive at the speed limit
C) Use your low beams and reduce speed
D) Turn on your hazard lights and keep driving
Answer: C) Use your low beams and reduce speed
Explanation: Low beams are less likely to reflect off fog and reduce visibility, helping you drive safely in foggy conditions.
40. What should you do when you are approached by an emergency vehicle?
A) Speed up to get out of the way
B) Stop immediately
C) Move to the right and stop, if possible
D) Continue driving at the same speed
Answer: C) Move to the right and stop, if possible
Explanation: Moving to the right and stopping gives emergency vehicles room to pass safely.
41. Which of the following is the primary function of a commercial vehicle’s air brakes?
A) To stop the vehicle as quickly as possible
B) To provide smooth braking over long distances
C) To prevent tire wear
D) To apply the brakes gradually
Answer: B) To provide smooth braking over long distances
Explanation: Air brakes allow for smoother, more gradual braking, which is essential for large commercial vehicles.
42. What is the legal blood alcohol concentration (BAC) limit for a commercial driver?
A) 0.08%
B) 0.04%
C) 0.10%
D) 0.00%
Answer: B) 0.04%
Explanation: For commercial drivers, the legal BAC limit is 0.04%. Driving with a higher BAC is prohibited.
43. What is the best way to prevent a rollover?
A) Brake sharply
B) Drive at lower speeds
C) Turn the steering wheel quickly
D) Overload the vehicle
Answer: B) Drive at lower speeds
Explanation: Driving at lower speeds and avoiding sharp turns reduces the risk of a rollover.
44. How should you react to a road hazard while driving a commercial vehicle?
A) Stop immediately
B) Maneuver the vehicle to avoid the hazard
C) Sound the horn
D) Ignore the hazard
Answer: B) Maneuver the vehicle to avoid the hazard
Explanation: You should safely maneuver around road hazards, always being cautious of traffic and obstacles.
45. What is the primary responsibility of a commercial driver in terms of cargo?
A) To ensure the cargo is properly secured
B) To calculate the weight of the cargo
C) To load the cargo
D) To estimate the cargo’s delivery time
Answer: A) To ensure the cargo is properly secured
Explanation: The commercial driver is responsible for ensuring that cargo is loaded and secured to prevent accidents or damage.
46. What is the function of the differential lock in a vehicle?
A) To lock the brakes
B) To prevent wheel slippage in low traction conditions
C) To increase speed
D) To lock the doors
Answer: B) To prevent wheel slippage in low traction conditions
Explanation: A differential lock helps prevent slippage by ensuring that both wheels on an axle rotate together.
47. What is the purpose of the “blind spot” in a commercial vehicle?
A) To keep the vehicle’s weight balanced
B) To provide space for cargo
C) To provide safety zones around the vehicle
D) To allow for larger mirrors
Answer: C) To provide safety zones around the vehicle
Explanation: Blind spots are areas around the vehicle that are difficult for the driver to see, requiring extra caution.
48. What is the main function of the governor in an air brake system?
A) To prevent overheating of the brakes
B) To regulate air pressure
C) To assist with parking
D) To control the speed of the vehicle
Answer: B) To regulate air pressure
Explanation: The governor controls the air pressure in the air brake system to ensure it stays within safe operating limits.
49. What is the safest distance to follow behind another vehicle?
A) One car length
B) Two seconds
C) Three seconds
D) Four seconds
Answer: C) Three seconds
Explanation: Maintaining a three-second following distance allows enough time to react in case the vehicle ahead stops suddenly.
50. When should you apply the parking brake on a commercial vehicle?
A) Only when parking on an incline
B) After the vehicle has come to a complete stop
C) While driving on the highway
D) Whenever you feel it is necessary
Answer: B) After the vehicle has come to a complete stop
Explanation: The parking brake should be applied after the vehicle has stopped to prevent it from rolling.
Sidhant Singh is a highly accomplished professional educator with a diverse academic background. He holds a Master’s degree in History, an MSc in Electrical Engineering and a PhD, demonstrating his extensive knowledge and expertise in both the humanities and the sciences. His unique combination of skills enables him to offer a well-rounded perspective in his teaching and research, making him a valuable resource for students across various fields.