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California CDL General Knowledge Test — Full Practice Exam + Answer Key (2026)

If you walk into the DMV cold, the California CDL general knowledge test is the one that humbles people. It's not the air brakes test. It's not combination vehicles. It's the 50-question writtens covering driver disqualifications, the 7-step inspection, basic control, shifting, signaling, distracted driving, and fatigued driving. Every section of the 2026 California Commercial Driver Handbook (DL 650) is fair game, and the DMV doesn't tell you which 50 questions you got from a pool of hundreds.

This is a full practice exam built straight from Sections 1 through 4 and Section 11 of the 2026 DL 650. Fifty questions. Real test format. Answer key with handbook section references at the bottom so you can go back and re-study any question you missed.

No login. No paywall. Just the work.

How the Real Test Works

Before you start, here's what you're actually walking into.

Test detailWhat to know
Number of questions50
Passing score80% (40 of 50 correct)
Time limitNone at most CA DMV offices
Question formatMultiple choice, 3-4 answers each
Retake feeAbout $8 per attempt
Max attempts per application3
Source materialDL 650, Sections 1, 2, and 11

Per the 2026 DL 650 (§1.1), you get three shots at the knowledge tests on one $53 application. Burn through them and you start the whole application over. Most California DMV offices won't make you wait between retakes, but you usually have to reschedule for a different day.

Real talk: Self-graded practice tests are worth nothing if you peek at the answers. Cover the answer key, take all 50 in one sitting, then grade yourself. Anything under 42 out of 50 means you're not ready for the real California CDL general knowledge test yet. Restudy the sections you missed and try again tomorrow.

Section A: Driver Disqualifications (Questions 1-8)

1. What is the maximum blood alcohol concentration (BAC) for a commercial driver while operating a CMV?

2. A first conviction for driving a CMV with a BAC of 0.04% or higher results in a CDL disqualification of at least:

3. If you commit a first offense for driving under the influence while operating a CMV placarded for hazardous materials, your CDL is disqualified for at least:

4. A second major offense (DUI, leaving the scene, felony with a CMV) gets your CDL disqualified for:

5. How many serious traffic violations in a 3-year period result in a 60-day CDL disqualification?

6. Which of the following is NOT a serious traffic violation?

7. The first violation of an out-of-service order results in a CDL disqualification of at least:

8. Within how many business days must you notify your employer if your license is suspended or revoked?

Section B: Vehicle Inspection (Questions 9-20)

9. What is the most important reason for inspecting your vehicle?

10. The minimum tread depth for the front tires of a CMV is:

11. Minimum tread depth on tires other than front tires is:

12. Steering wheel play of more than how many degrees can make a CMV hard to steer?

13. Three types of required emergency equipment are:

14. How many red reflective triangles must you carry?

15. Air pressure should build from 50 psi to 90 psi within how many minutes?

16. When testing hydraulic brakes for leaks, pump the brake 3 times then hold firm pressure for:

17. Cargo securement on trucks must be inspected within the first ____ miles of a trip, then every 150 miles or 3 hours after.

18. During the CDL vehicle inspection test, you must:

19. Reflectors on the rear of a vehicle should be what color?

20. During the walk-around inspection, you start by turning on which signal?

Real talk: Section 11 of the DL 650 is where most self-study drivers underprepare. The general knowledge writtens pull questions from both Section 2.1 and Section 11, and they overlap but aren't identical. Read both. If you only memorize one, you'll see questions you've never seen wording for.

Section C: Basic Vehicle Control (Questions 21-26)

21. When you start moving on a hill with a manual transmission, how do you keep from rolling back?

22. When backing a CMV, you should:

23. When backing, the safest direction to turn is:

24. When backing a trailer, you turn the steering wheel:

25. The most important hand signal to agree on with your helper before backing is:

26. When the drive wheels begin to spin during acceleration in rain or snow, you should:

Section D: Shifting Gears (Questions 27-31)

27. Most heavy vehicles with an unsynchronized manual transmission require:

28. The two ways to know when to shift up are:

29. You should downshift before:

30. Retarders should be turned OFF when:

31. With an automatic transmission, you can select a lower range to get:

Section E: Communicating (Questions 32-36)

32. Three rules for using turn signals are: signal early, signal continuously, and:

33. When you must stop on a divided highway, you must place your warning devices within:

34. On a divided highway stop, you place the three warning triangles at:

35. If you stop just past a hill or curve that blocks the view, you should:

36. When passing a slower vehicle at night, you should:

Section F: Distracted Driving (Questions 37-42)

37. While operating a CMV in California, you may use a mobile phone only if:

38. Texting while driving a CMV increases the odds of a safety-critical event by how many times?

39. At 55 mph, an average texting glance of 4.6 seconds means traveling roughly how far without looking at the road?

40. A second conviction for hand-held cell phone use while operating a CMV within a 3-year period results in CDL disqualification of:

41. Hands-free devices are:

42. Which is an example of both physical and mental distraction?

Section G: Fatigued Driving and Stopping (Questions 43-50)

43. The only true cure for fatigue is:

44. A warning sign of fatigue is:

45. Total stopping distance is:

46. At 55 mph on dry pavement with good brakes, total stopping distance is approximately:

47. When the road is wet, you should reduce your speed by about:

48. On packed snow, reduce your speed by:

49. Hydroplaning can occur at speeds as low as:

50. When approaching a railroad-highway grade crossing, failing to obey a traffic control device results in a first-offense CDL disqualification of at least:

Answer Key (with DL 650 Handbook References)

Don't skim this. Every wrong answer is a section you need to reread.

  1. C - 0.04%. (DL 650 §1.3.2)
  2. C - 1 year. (DL 650 §1.3.2)
  3. B - 3 years for first offense in a HazMat-placarded vehicle. (DL 650 §1.3.2)
  4. D - Lifetime. (DL 650 §1.3.2)
  5. B - 2 serious violations in 3 years = 60-day disqualification. (DL 650 §1.3.3)
  6. D - Failure to signal is not on the serious-violation list. Following too closely, reckless driving, and improper lane changes are. (DL 650 §1.3.3)
  7. B - 90 days for first OOS violation. (DL 650 §1.3.4)
  8. B - 2 business days. (DL 650 §1.4)
  9. B - Safety. (DL 650 §2.1.1)
  10. B - 4/32 inch on front tires. (DL 650 §2.1.3)
  11. A - 2/32 inch on other tires. (DL 650 §2.1.3)
  12. B - More than 10 degrees (about 2 inches at the rim of a 20-inch wheel). (DL 650 §2.1.3)
  13. B - Fire extinguisher, spare fuses, warning devices. (DL 650 §2.1.3)
  14. C - 3 red reflective triangles, or 6 fuses, or 3 liquid-burning flares. (DL 650 §2.1.3)
  15. C - 3 minutes. (DL 650 §2.1.5)
  16. B - 5 seconds, no movement. (DL 650 §2.1.5)
  17. B - Within the first 50 miles. (DL 650 §2.1.6)
  18. B - Point to or touch, name, and explain. (DL 650 §2.1.4 and §11.7)
  19. C - Red at the rear. (DL 650 §2.1.5)
  20. B - Right turn signal, then walk around starting from the left front. (DL 650 §2.1.5)
  21. B - Partly engage the clutch first. (DL 650 §2.2.1)
  22. B - Slow, lowest reverse gear. (DL 650 §2.2.4)
  23. B - Driver's side so you can see. (DL 650 §2.2.4)
  24. B - Opposite direction (then correct as the trailer turns). (DL 650 §2.2.5)
  25. C - "Stop." (DL 650 §2.2.4)
  26. C - Take your foot off the accelerator. (DL 650 §2.2.1)
  27. B - Double clutching. (DL 650 §2.3.1)
  28. A - Engine speed (rpm) and road speed (mph). (DL 650 §2.3.1)
  29. C - Both before curves and before downgrades. (DL 650 §2.3.1)
  30. B - Wet, icy, or snow-covered roads. Retarders can cause drive wheels to skid. (DL 650 §2.3.4)
  31. B - Engine braking on downgrades. (DL 650 §2.3.3)
  32. A - Cancel after turning. (DL 650 §2.5.1)
  33. B - Within 10 minutes. (DL 650 §2.5.2)
  34. B - 10 feet, 100 feet, 200 feet toward approaching traffic. (DL 650 §2.5.2)
  35. B - Move the rear-most triangle back down past the obstruction (within 500 feet). (DL 650 §2.5.2)
  36. B - Flash high to low beam at night, or tap the horn lightly by day. (DL 650 §2.5.2)
  37. B - Hands-free, single-button or voice-activated. (DL 650 §2.9.4)
  38. D - 23.2 times. (DL 650 §2.9.5)
  39. C - 371 feet, roughly the length of a football field. (DL 650 §2.9.5)
  40. B - 60 days for the second offense within 3 years. (DL 650 §1.3.9 and §2.9.4)
  41. C - Hands-free is no less likely to cause distraction. (DL 650 §2.9.4)
  42. C - Texting and phone use combine physical and mental distraction. (DL 650 §2.9.3)
  43. C - Rest. No drug or stimulant cures fatigue. (DL 650 §2.11.2)
  44. A - Daydreaming and missing exits/signs. (DL 650 §2.11.2)
  45. C - Perception + reaction + braking. (DL 650 §2.6.1)
  46. C - 419 feet at 55 mph. (DL 650 §2.6.1)
  47. C - Reduce by 1/3 on wet roads. (DL 650 §2.6.2)
  48. C - Half or more on packed snow. (DL 650 §2.6.2)
  49. B - As low as 30 mph if standing water is present. (DL 650 §2.6.2)
  50. B - 60 days for first railroad-grade-crossing violation. (DL 650 §1.3.5)

How to Use This Practice Exam

Score yourself honestly. Here's what your number means.

Your scoreWhat it meansNext step
47-50Strong. You're test-ready.Schedule the DMV. Don't sit on the CLP.
42-46Pass-zone, but tight.Restudy missed sections. Retake in 2 days.
35-41Borderline. You'd squeak by or fail.Read DL 650 §1, §2, and §11 cover to cover.
Under 35Not ready.Slow down. Don't book the DMV yet.

A few things that separate drivers who pass on the first try from drivers who fail:

Real talk: The DMV's question bank is bigger than 50. You'll see questions on the California CDL general knowledge test that aren't here, and you'll see questions here that don't show up on your test. Practice tests work because they teach you how California asks questions, not because they leak the exact wording. Memorize the handbook, not the practice test.

Going Deeper

If you missed more than 8 questions, you've got real gaps. Some of the most useful follow-up reads while you keep prepping:

Pass on the first try

The California CDL general knowledge test rewards drivers who treat the DL 650 like a job rather than a textbook. If you want all 440+ practice questions, every memory trick for the danger numbers, and the full pre-trip walkthrough in one place, grab the California CDL Master Guide. It's $39, one-time, with a 30-day refund. Built directly from the 2026 DL 650 so nothing you study is outdated.

Pass the writtens. Pass the pre-trip. Get behind the wheel.

Sources: California Commercial Driver Handbook (DL 650, 2026 ed.) Sections 1.3, 2.1-2.6, 2.9, 2.11, and 11. Per CFR Title 49 Parts 383 and 391. Question wording is original; all facts and section references verified against the official handbook.

Last updated: May 17, 2026

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