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

178

CDL General Knowledge Test 5

1 / 50

In the event of an engine fire,

A) always open the hood to release the fire.

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

C) keep the engine running and use extinguishers.

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

2 / 50

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

A) Push on until your next stop and rest.

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

C) Take a half-hour coffee stop

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

3 / 50

If your vehicle is involved in an accident, try to

A) stop all traffic in other lanes.

B) honk your horn to warn other vehicles.

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

D) get it to the side of the road.

4 / 50

Which of the following statements about tie downs is true?

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

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

C) 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

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

5 / 50

You should use your mirrors to check

A) the condition of tires.

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

C) All of the above

D) traffic gaps when merging.

6 / 50

Which of the following statements about tank vehicles is true?

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

B) Tank vehicles transport liquids only.

C) Special skills are required to haul liquid tanks.

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

7 / 50

Two possible causes of tire fires are

A) short circuits and duals that touch.

B) under-inflated tires and duals that touch.

C) improperly loaded cargo and driver smoking.

D) improper fueling or loose fuel connections.

8 / 50

Outage is

A) the weight of the liquid in transit

B) the space allotted for expanding liquids.

C) caused by liquid surge.

D) a full liquid tanker.

9 / 50

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

A) only transport liquid hazardous materials.

B) not transport any type of hazardous material.

C) transport hazardous materials if your employer lets you.

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

10 / 50

You must keep shipping papers for hazardous materials

A) in the glove compartment.

B) under the passenger’s seat.

C) with the hazardous materials.

D) in a pouch on the driver’s door.

11 / 50

When driving baffled liquid tanks,

A) there is no risk of rollover.

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

C) forward and backward liquid surge is controlled.

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

12 / 50

For electrical fires and burning liquids, use

A) a B:C type fire extinguisher only.

B) water

C) whatever is available at the time.

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

13 / 50

To correct a drive-wheel braking skid you should

A) countersteer.

B) brake harder.

C) turn slowly

D) keep your foot off the clutch.

14 / 50

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

A) 12-15 seconds

B) 1-2 seconds

C) 5-8 seconds

D) 18-21 seconds

15 / 50

Which of the following about covering cargo is NOT true?

A) You need to protect people from spilled cargo.

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

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

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

16 / 50

For cargo, blocking is

A) shaped to fit loosely over the cargo

B) unattached to the cargo deck.

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

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

17 / 50

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

A) Look directly at oncoming headlights briefly.

B) Wear sunglasses to reduce headlight glare.

C) Keep your instrument lights bright.

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

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

D) always apply the brakes immediately

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

B) keeping one set of wheels on the pavement.

C) All of the above

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

20 / 50

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

A) move to the left.

B) brake immediately.

C) move to the right.

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

21 / 50

Which of the following is true about drinking and driving?

A) Alcohol increases your ability to drive farther.

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

C) A drink will wake up a sleepy driver.

D) Alcohol will reduce your ability to drive.

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

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

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

23 / 50

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

A) Forward and back liquid surge is reduced

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

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

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

24 / 50

When transporting cargo, inspect the materials and securing devices

A) before the trip only.

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

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

D) before and after the trip.

25 / 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.

26 / 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) Use the parking or emergency brake

C) Shift down

D) Pump the brakes

27 / 50

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

A) increase acceleration.

B) let the vehicle slow down.

C) brake hard.

D) turn sharply.

28 / 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) notify authorities.

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

C) keep the injured person(s) cool.

D) park your vehicle near the accident.

29 / 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) Check all tires after stopping.

C) Stay off the brake.

D) Hold the steering wheel firmly.

30 / 50

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

A) brake hard at all stops.

B) adjust to conditions while driving.

C) turn the wheel sharply for all turns.

D) accelerate to give power to the drive wheels.

31 / 50

f you are transporting livestock,

A) rollover is less likely.

B) there is always a high center of gravity.

C) give livestock enough room to roam freely.

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

32 / 50

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

A) drive to the closest service station for assistance.

B) keep the doors shut.

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

D) keep the doors open

33 / 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 to lock the wheels.

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

34 / 50

Dry bulk tanks and hanging meat

A) are unstable loads.

B) handle better than most cargo on sharp turns.

C) have low centers of gravity.

D) do not require special care.

35 / 50

if you are driving a long distance, you should

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

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

C) do some physical exercises after the trip.

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

36 / 50

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

A) Running stop signs

B) All of the above

C) Making quick, jerky movements

D) Driving in the wrong lane

37 / 50

Since you cannot inspect sealed loads, you

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

B) can exceed gross weight and axle weight limits.

C) therefore need special tie down devices.

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

38 / 50

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

A) The vehicle is less likely to tip over.

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

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

D) The vehicle is less dangerous on curves.

39 / 50

To prevent truck fires, you should inspect your vehicle

A) after the trip only.

B) before, during, and after the trip.

C) before and after the trip.

D) before the trip only.

40 / 50

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

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

B) using over-the-counter drugs

C) using alcohol.

D) using amphetamines.

41 / 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 diamond-shaped labels on the containers.

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

D) only on the shipping papers.

42 / 50

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

A) You do not need a special permit.

B) Driving is usually limited to certain times.

C) Special equipment may be necessary.

D) You may require a police escort.

43 / 50

A coupling device capacity is the

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

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

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

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

44 / 50

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

A) only the driver should know

B) everyone who handles the material should know.

C) only the shipper should know.

D) the shipper and the driver should know.

45 / 50

Which of the following contains more alcohol?

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

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

C) All three contain the same amount of alcohol.

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

46 / 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.

47 / 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) You must be aware of legal weight limits

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

D) Heavy or dense liquids do not expand.

48 / 50

The Gross Combination Weight Rating is the

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

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

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

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

A) Front-end header boards

B) Tie downs

C) Bracing devices

D) Blocking devices

50 / 50

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

A) The vehicle’s stopping distance decreases.

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

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

D) All of the above

Your score is

The average score is 78%

CDL Knоwlеdgе Test (50 Questions Each)

School Bus Endorsement

Air Brakes Endorsement

Combination vehicles Endorsements

Doubles and Triples Endorsement

Tank Endorsement

Hazardous Material

Passenger Endorsement

Metal Coil Endorsement

CDL Metal Coil Endorsement Practice Test 2025