CDL General Knowledge Practice Test 2025

CDL General Knowledge Practice Test 2025 Commercial Driver’s License Permit Test (CDL) in the USA: Try our free original CDL Knowledge Practice questions answers.

There is a total of 50 CDL General Knowledge Practice Question Answers with explanations.  You must pass the written test for the CDL that you need. In general, the CDL general knowledge test is required to be taken by all CDL applicants. The CDL test consists of 50 questions. To pass, you must correctly answer at least 40 questions (80%).

CDL General Knowledge Practice Test

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 Yes
0%
0 votes, 0 avg
453

CDL General Knowledge Practice Test 1

1 / 50

How far ahead should you look?

2 / 50

A vehicle must be equipped with 3 kinds of emergency equipment. Which of the following is NOT one of them?

3 / 50

If your brakes fail on a long downgrade, your best bet is to

4 / 50

You should turn retarders on whenever the road is wet, icy, or snow covered.

5 / 50

For vehicles with automatic transmissions, you can select a low range to get greater engine braking when going down grades.

6 / 50

During a vehicle inspection test, you should put the starter switch key in your pocket

7 / 50

If you are driving a 30 foot vehicle at 55 mph, how many seconds of following distance should you allow?

8 / 50

When backing a vehicle, you should back and turn towards what side?

9 / 50

What are special conditions in which you should downshift?

10 / 50

If you are being tailgated, what should you NOT do?

11 / 50

What are the ways to know when to shift?

12 / 50

What is the most important hand signal you can your helper should agree on?

13 / 50

Hydroplaning is more likely when tire pressure is high.

14 / 50

If you are driving a 30 foot vehicle at 35 mph, how many seconds of following distance should you allow?

15 / 50

Most people can tell when they are sleepy or about to fall asleep.

16 / 50

For use as warning devices for parked vehicles, how many red reflective triangle should you carry?

17 / 50

To determine how many seconds of following distance space you have, wait until a vehicle ahead passes a shadow on the road, a pavement marking, or some other clear landmark and then count the seconds until you reach the same spot and then double it.

18 / 50

What is the minimum tread depth for tires?

19 / 50

Wheel bearing seals should be checked for

20 / 50

When water collects on the road and your tires lose contact with the road, this is called

21 / 50

Which of the following is a NOT a steering system part?

22 / 50

You must turn your headlights on

23 / 50

Empty trucks require greater stopping distance.

24 / 50

The act of operating a motor vehicle in a selfish, bold, or pushy manner, without regard for the rights and safety of others is called:

25 / 50

During very hot weather, you should let the air out the tires to prevent a blowout.

26 / 50

When driving in very hot weather, how often should you check the tires?

27 / 50

Drivers signaling a turn may be a hazard.

28 / 50

When should a vehicle be inspected?

29 / 50

To test hydraulic brakes for leaks, pump the pedal 3 times. Then apply firm pressure to the pedal and hold for 5 seconds. The pedal should move. If it doesn’t, there may be a leak or other problem.

30 / 50

A thin layer of ice that is clear enough that you can see the road underneath is called

31 / 50

If an aggressive driver is involved in an accident, you should stop immediately and help them; the same as you would for any other driver.

32 / 50

Why is it important to use a helper when backing a vehicle?

33 / 50

Driving with wet brakes can cause which of the following. Choose all that apply

34 / 50

You should shift your transmission to a low gear before starting a downgrade.

35 / 50

Which of the following factors should you take into consideration when determining a safe speed for going down a long, steep downgrade? Choose all that apply.

36 / 50

When stopped on a hill, how do you prevent a vehicle from rolling back?

37 / 50

The total stopping distance is reaction distance plus braking distance.

38 / 50

When doubling your speed, your braking distance is

39 / 50

Which of the following is NOT a suspension system defect?

40 / 50

Stopping is not always the safest thing to do in an emergency.

41 / 50

If there is no white stop line painted on the pavement of a railroad crossing, vehicles that are required to stop must stop:

42 / 50

If weather conditions require the use of windshield wipers, you must also turn on your headlights.

43 / 50

If an oncoming driver had drifted into your lane, what should you do?

44 / 50

When should a vehicle be inspected?

45 / 50

Antifreeze is only necessary when driving in cold weather conditions

46 / 50

What types of vehicles can get stuck on a railroad crossing?

47 / 50

When is it safe to remove the radiator cap?

48 / 50

How long does it take a typical tractor trailer unit to clear a double track?

49 / 50

When going down a long and/or steep downgrade, you should release the brakes after your speed has been reduced to:

50 / 50

Where should your reflectors be placed when stopped on a divided highway?

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The average score is 73%