CDL General Knowledge Test (50 Questions Answers)

CDL General Knowledge Test (50 Questions Answers): If you are preparing to take the Commercial Driver’s License Exam, you’ve visited the right page. Our CDL General Knowledge Test (50 Questions) is an essential part of your preparation for the exam. It’s been proven that the more questions you answer before taking the exam, the better you will ultimately do on the final test.

If you have enough time to prepare, take each test on separate days and bring them to a quiet room, under simulated test conditions. When you’re done, check your answers and then check your score. As you go through the CDL Quiz, you will find that there are some areas that may require additional review, based on your previous knowledge or the results of the CDL practice tests.

CDL General Knowledge Test (50 Questions)

Test Name	CDL Practice Test 2025
Language	English
License	CDL (Class A, B, or C),
Total Questions	50 Knowledge Practice Test
Test For	Commercial Driver License
Test Preparation	Driving Knowledge
Country	USA
Explanation	No

0 votes, 0 avg

218

CDL General Knowledge Test 5

1 / 50

Which of the following contains more alcohol?

A) A 5-ounce glass of wine with an alcohol content of 12% by volume

B) All three contain the same amount of alcohol.

C) A 12-ounce mug of beer with an alcohol content of 5% by volume

D) A 1 1/2nce shot of 80-proof liquor

2 / 50

You are driving a vehicle when two cars collide a short distance ahead of you. In order to safely avoid the accident, you should

A) urn quickly with one hand on the wheel and one hand on the horn

B) make a sharp turn to clear the accident area

C) always apply the brakes immediately

D) grip the wheel firmly with both hands and turn only the amount of space needed to clear whatever is in your way

3 / 50

A coupling device capacity is the

A) maximum weight the device can pull and/or carry.

B) maximum safe weight a tire can carry at a specified pressure.

C) manufacturer’s weight capacity rating of the suspension system.

D) weight transmitted to the ground by one axle or one set of axles.

4 / 50

Which of the following statements about a vehicle with a high center of gravity is true?

A) The cargo is evenly distributed and as low as possible.

B) The vehicle is less dangerous on curves.

C) The vehicle is less likely to tip over.

D) The cargo should be rearranged so that the heaviest parts of the cargo are under the lightest parts.

5 / 50

You see an accident on the road and wish to help. The steps you take to prevent further damage or injury are: protect the area, care for the injured, and

A) park your vehicle near the accident.

B) notify authorities.

C) always move the severely injured person(s) away from the accident.

D) keep the injured person(s) cool.

6 / 50

f an oncoming driver has suddenly drifted into your lane or if an obstacle suddenly blocks your path, you should

A) brake immediately.

B) move to the right.

C) move to the left.

D) apply brakes slowly and signal for a lane change.

7 / 50

When a front-wheel skid occurs, the only way to stop the skid is to

A) turn sharply.

B) brake hard.

C) increase acceleration.

D) let the vehicle slow down.

8 / 50

Dry bulk tanks and hanging meat

A) do not require special care.

B) are unstable loads.

C) handle better than most cargo on sharp turns.

D) have low centers of gravity.

9 / 50

Possession or use of drugs while on duty is prohibited by law except when

A) using alcohol.

B) using over-the-counter drugs

C) your doctor informs you that the certain drug prescribed will not affect safe driving abilities.

D) using amphetamines.

10 / 50

In the event of a cargo fire in a van or box trailer, you should

A) park close to the road so other vehicles can see the danger and call for assistance.

B) keep the doors open

C) keep the doors shut.

D) drive to the closest service station for assistance.

11 / 50

Which of the following statements is NOT true about an overloaded vehicle?

A) The vehicle’s stopping distance decreases.

B) The vehicle may gain too much speed on downgrades.

C) All of the above

D) The vehicle will have to go very slowly on upgrades.

12 / 50

if you are driving a long distance, you should

A) take a short break once or twice during the trip when you are feeling tired or drowsy.

B) avoid short breaks, but keep the window open.

C) do some physical exercises after the trip.

D) stop often and take short breaks before you feel really drowsy or tired.

13 / 50

A tank vehicle with a high center of gravity

A) should take highway curves or on-ramp/off-ramp curves at least five miles above the posted speed.

B) cannot turn over at the speed limit posted for curves.

C) is top-heavy, but not easy to rollover.

D) should take highway curves or on-ramp/off-ramp curves well below the posted speeds.

14 / 50

For cargo, blocking is

A) unattached to the cargo deck.

B) shaped to fit loosely over the cargo

C) used in the front, back and/or sides of a piece of cargo

D) needed in the front of a piece of cargo only

15 / 50

Which of the following statements about loading heavy or dense liquid is true?

A) The weight of the actual liquid does not matter.

B) Tanks carrying heavy liquids can sometimes be filled completely.

C) Heavy or dense liquids do not expand.

D) You must be aware of legal weight limits

16 / 50

Which of the following is a good thing to do when driving at night?

A) Keep your speed slow enough that you can stop within the range of your headlights.

B) Wear sunglasses to reduce headlight glare.

C) Keep your instrument lights bright.

D) Look directly at oncoming headlights briefly.

17 / 50

Outage is

A) a full liquid tanker.

B) caused by liquid surge.

C) the space allotted for expanding liquids.

D) the weight of the liquid in transit

18 / 50

Which of the following is true about drinking and driving?

A) A drink will wake up a sleepy driver.

B) Alcohol will reduce your ability to drive.

C) Coffee and a little fresh air will help sober up a driver who is about to drive.

D) Alcohol increases your ability to drive farther.

19 / 50

If your vehicle is involved in an accident, try to

A) get it to the side of the road.

B) stop all traffic in other lanes.

C) honk your horn to warn other vehicles.

D) keep one empty lane between your vehicle and other traffic.

20 / 50

f you are transporting livestock,

A) there is always a high center of gravity.

B) give livestock enough room to roam freely.

C) rollover is less likely.

D) use false bulkheads with less than a full load.

21 / 50

For electrical fires and burning liquids, use

A) water

B) an A:B:C or B:C type fire extinguisher.

C) whatever is available at the time.

D) a B:C type fire extinguisher only.

22 / 50

To correct a drive-wheel braking skid you should

A) keep your foot off the clutch.

B) turn slowly

C) countersteer.

D) brake harder.

23 / 50

____________ protect you from your cargo in case of collision and should be inspected for good condition.

A) Blocking devices

B) Tie downs

C) Bracing devices

D) Front-end header boards

24 / 50

When driving baffled liquid tanks,

A) bulkheads are included which stop side to side liquid surge.

B) here is no risk involved in taking curves or making sharp turns at the posted limits.

C) there is no risk of rollover.

D) forward and backward liquid surge is controlled.

25 / 50

You have been driving for a long time and you are feeling tired. What should you do?

A) Take an over-the-counter drug that will keep you awake.

B) Push on until your next stop and rest.

C) Take a half-hour coffee stop

D) Make an early stop and sleep or pull off the road and nap.

26 / 50

n some emergencies, you may have to drive off the road and onto the shoulder in order to avoid collision with another vehicle. If possible, you should avoid

A) All of the above

B) keeping one set of wheels on the pavement.

C) coming to a complete stop before returning to the road.

D) using the brake until your speed has dropped to about 20 mph

27 / 50

A skid happens when tires lose their grip on the road. To prevent skidding, you should

A) turn the wheel sharply for all turns.

B) accelerate to give power to the drive wheels.

C) adjust to conditions while driving.

D) brake hard at all stops.

28 / 50

Poor weight balance can make vehicle handling unsafe. Hard steering is caused by

A) underloaded front axles.

B) a high center of gravity.

C) too little weight on the driving axles.

D) too much weight on the steering axle.

29 / 50

You must keep shipping papers for hazardous materials

A) in the glove compartment.

B) under the passenger’s seat.

C) in a pouch on the driver’s door.

D) with the hazardous materials.

30 / 50

To turn quickly and safely in the event of a traffic or vehicle emergency, you should be prepared to countersteer. This means you turn the wheel

A) to the right of the obstacle.

B) the opposite direction of the obstacle.

C) to the left of the obstacle.

D) away from the obstacle and then back in the other direction.

31 / 50

Which of the following statements about tank vehicles is true?

A) The term “tank vehicle” refers only to those vehicles having a permanently attached tank.

B) All tank vehicles have some sort of bulkhead or baffle.

C) Tank vehicles transport liquids only.

D) Special skills are required to haul liquid tanks.

32 / 50

In the event of an engine fire,

A) keep the engine running and use extinguishers.

B) try to keep the hood closed and shoot extinguishers through louvers or from the underside of the vehicle.

C) always open the hood and shoot extinguishers through louvers or from the underside of the vehicle.

D) always open the hood to release the fire.

33 / 50

Two possible causes of tire fires are

A) under-inflated tires and duals that touch.

B) improper fueling or loose fuel connections.

C) short circuits and duals that touch.

D) improperly loaded cargo and driver smoking.

34 / 50

The Federal Hazardous Materials Table names materials that are hazardous. If you are transporting any of these materials,

A) only the shipper should know.

B) the shipper and the driver should know.

C) everyone who handles the material should know.

D) only the driver should know

35 / 50

Shippers must write the name of the hazard class of hazardous products

A) on the shipping papers and on the diamond-shaped labels or special tags on the container.

B) only on the shipping papers.

C) only on the diamond-shaped labels on the containers.

D) only on the special-fitting tags for the containers

36 / 50

To prevent truck fires, you should inspect your vehicle

A) before and after the trip.

B) before the trip only.

C) after the trip only.

D) before, during, and after the trip.

37 / 50

To stop quickly and safely, you can use which of the controlled braking methods?

A) Apply the brakes but keep them released before and after you make steering adjustments.

B) Apply the brakes and make large steering adjustments.

C) Apply the brakes as hard as you can without locking the wheels.

D) Apply the brakes as hard as you can to lock the wheels.

38 / 50

Which of the following should you NOT do in the event of air brake failure where there was a major air leak in the system?

A) Find an escape route

B) Shift down

C) Pump the brakes

D) Use the parking or emergency brake

39 / 50

Which of the following statements about driving an over-length, over- width, and/or over-weight load is NOT true?

A) Driving is usually limited to certain times.

B) You do not need a special permit.

C) Special equipment may be necessary.

D) You may require a police escort.

40 / 50

You should use your mirrors to check

A) the condition of tires.

B) All of the above

C) traffic gaps when merging.

D) where the rear of your vehicle is while turning.

41 / 50

Which of the following statements about unbaffled or “smooth bore” liquid tankers is NOT true?

A) You must be extremely cautious, especially when starting and stopping.

B) There is nothing inside the tank to slow down the flow of liquid

C) Food products will most likely be transported in an unbaffled liquid tank

D) Forward and back liquid surge is reduced

42 / 50

Which of the following about covering cargo is NOT true?

A) You need to protect people from spilled cargo.

B) You should look at your cargo in the mirrors often while driving.

C) You need to protect the cargo from the weather.

D) Flapping covers need not be tied down as long as the bulk of the cargo is covered.

43 / 50

Which of the following is an effect of drinking and driving?

A) Making quick, jerky movements

B) Driving in the wrong lane

C) All of the above

D) Running stop signs

44 / 50

Which of the following statements about tie downs is true?

A) The combined strength of all cargo tie downs must be strong enough to lift one-and-a-half-times the weight of the piece of cargo tied down

B) They go from the upper part of the cargo to the floor and/or walls of the cargo compartment.

C) Tie downs can be of any type or strength.

D) Cargo should have at least one tie down for each 20 feet of cargo.

45 / 50

When transporting cargo, inspect the materials and securing devices

A) within 50 miles after beginning the trip and during every driving break.

B) before the trip only.

C) before and after the trip.

D) before the trip, within 50 miles after beginning the trip, after every 3 hours or 150 miles, and during every driving break.

46 / 50

f you do not have a Hazardous Materials Endorsement on your Commercial Driver License, you can

A) transport hazardous materials if your employer lets you.

B) not transport any type of hazardous material.

C) only transport liquid hazardous materials.

D) drive a vehicle that carries hazardous materials if it does not require placards.

47 / 50

How far ahead should a driver look ahead of the vehicle while driving?

A) 18-21 seconds

B) 5-8 seconds

C) 12-15 seconds

D) 1-2 seconds

48 / 50

The Gross Combination Weight Rating is the

A) maximum total weight of a single vehicle plus its load specified by the manufacturer.

B) total weight of a single vehicle plus its load.

C) maximum total weight of a power unit plus trailer(s) plus the cargo as specified by the manufacturer.

D) total weight of a powered unit plus trailer(s) plus the cargo.

49 / 50

Which of the following should you NOT do if you suspect that one of your vehicle’s tires has blown out?

A) Keep driving until you are certain it was one of your vehicle’s tires that blew.

B) Hold the steering wheel firmly.

C) Check all tires after stopping.

D) Stay off the brake.

50 / 50

Since you cannot inspect sealed loads, you

A) must be lower than weight limits by 50 pounds.

B) therefore need special tie down devices.

C) can exceed gross weight and axle weight limits.

D) should therefore check that you do not exceed gross weight and axle weight limits.

Your score is

The average score is 77%

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