California CDL Practice Test 2026 — 50 Free Questions With Answer Explanations

Free questions. Real handbook citations. No email signup, no scroll-trap, no AI-generated nonsense pulled from a 2014 study site.

If you're studying for the California CDL, this california cdl practice test 2026 is built from the 2026 CA Commercial Driver Handbook (DL 650) — the same book the DMV writes the actual test from. Every answer below traces to a specific section and page of that handbook. If a question feels off, you can verify it yourself.

Real talk: Most "free CDL practice tests" online are recycled from the federal CDL manual, not the California one. California uses its own handbook with its own numbers (CVC sections, CHP procedures, in-state speed limits). Studying from a generic test means walking into the DMV with the wrong answers locked into your brain.

What's actually on the California CDL test

California's CDL knowledge testing is broken into separate exams. You only take the ones that match the license class and endorsements you want:

Per the handbook (§1.1.1), all knowledge tests are administered through the Automated Knowledge Testing system at any DMV field office. No testing aids — bring nothing into the test station.

This california cdl practice test 2026 covers the three exams that 90% of new applicants need:

• 25 General Knowledge questions (Sections 1–4 and 11)
• 15 Air Brakes questions (Section 5)
• 10 Combination Vehicles questions (Section 6)

Answers and handbook citations are at the bottom. Take the test cold. Don't peek. Then check yourself.

Section 1 — General Knowledge (25 questions)

1. What is the minimum tread depth required for the front (steering) tires of a CMV in California?

1. 2/32 inch
2. 4/32 inch
3. 6/32 inch
4. 8/32 inch

2. What is the minimum tread depth for all other tires (not steering)?

1. 1/32 inch
2. 2/32 inch
3. 4/32 inch
4. 6/32 inch

3. A leaf spring with how many missing or broken leaves puts the vehicle out-of-service?

1. Any one leaf
2. 1/8 or more
3. 1/4 or more
4. 1/2 or more

4. The maximum allowable steering wheel play is:

1. 5 degrees
2. 10 degrees
3. 15 degrees
4. 20 degrees

5. Which combination of warning devices is legal to carry for a parked CMV?

1. 3 red reflective triangles
2. 6 fuses
3. 3 liquid burning flares
4. Any one of the above

6. How do you test hydraulic brakes for leaks?

1. Pump the pedal 5 times, hold for 3 seconds
2. Pump the pedal 3 times, hold for 5 seconds; pedal should not move
3. Apply once and listen for 10 seconds
4. Press to the floor; if it goes to the floor, brakes are fine

7. The service brake stopping test on the skills exam is performed at what speed?

1. About 5 mph
2. About 15 mph
3. About 25 mph
4. Highway speed

8. Why do you put the starter switch key in your pocket during a pre-trip inspection?

1. So you don't lose it
2. So nobody else can move the vehicle while you walk around it
3. To save the battery
4. So the alarm engages

9. At 55 mph on dry pavement with good brakes, the total stopping distance for a loaded CMV is approximately:

1. 100 feet
2. 200 feet
3. 419 feet
4. 600 feet

10. The average perception time for an alert driver is:

1. 1/4 second
2. 1/2 second
3. 1 3/4 seconds
4. 3 seconds

11. If you double your speed from 20 to 40 mph, your braking distance increases by:

1. 2 times
2. 3 times
3. 4 times
4. 8 times

12. On a wet road, you should reduce your speed by approximately:

1. 1/10
2. 1/4
3. 1/3
4. 1/2

13. On packed snow, you should reduce your speed by:

1. 1/4
2. 1/3
3. 1/2 or more
4. Speed makes no difference once you have ABS

14. Hydroplaning can occur at speeds as low as:

1. 10 mph
2. 20 mph
3. 30 mph
4. 55 mph only

15. Using the heavy vehicle following-distance rule, how many seconds should you allow behind the vehicle ahead in a 40-foot truck traveling 35 mph?

1. 2 seconds
2. 3 seconds
3. 4 seconds
4. 5 seconds

16. When you drive a 40-foot truck above 40 mph, how many seconds of following distance do you need?

1. 3
2. 4
3. 5
4. 7

17. After loading flatbed cargo, you must inspect the securement within the first ___ miles and again every ___ miles or 3 hours after.

1. 25 / 100
2. 50 / 150
3. 100 / 200
4. 200 / 500

18. On a flatbed, cargo must have a minimum of:

1. One tie-down for every 20 feet of cargo
2. One tie-down for every 10 feet of cargo
3. Two tie-downs total, regardless of length
4. Tie-downs are only required over 30 feet

19. The minimum number of tie-downs for any flatbed load, no matter how short, is:

1. 1
2. 2
3. 3
4. 4

20. You drove a vehicle today. How long must you keep a copy of your inspection report in the vehicle?

1. 8 hours
2. 1 day
3. 1 week
4. 30 days

21. It is illegal to operate a CMV in California with a blood alcohol concentration (BAC) of:

1. 0.02% or higher
2. 0.04% or higher
3. 0.08% or higher
4. Any detectable amount

22. When you must back a CMV, you should:

1. Always back toward the passenger side
2. Always back toward the driver's side whenever possible
3. Back in any direction — both sides are equally safe
4. Use the highest reverse gear available

23. When stopped on a divided highway, where do you place your three reflective triangles?

1. 10, 50, 100 feet behind the vehicle
2. 10 feet ahead, 100 feet behind, 200 feet behind
3. 10, 100, and 200 feet behind the vehicle, toward approaching traffic
4. 100, 200, 300 feet behind the vehicle

24. When making a right turn in a long combination vehicle, you should:

1. Swing wide to the left before starting the turn so the trailer clears
2. Keep the rear of your vehicle close to the curb and turn wide as you complete the turn
3. Take both lanes at all times
4. Stop in the intersection until traffic clears

25. You see brake lights of vehicles slowing far ahead. The handbook says good drivers look:

1. 1–2 seconds ahead
2. 5 seconds ahead
3. 12–15 seconds ahead
4. As far as their headlights reach, regardless of speed

Studying off this practice test alone won't get you across the finish line

50 questions is a strong warmup. The DMV writes its General Knowledge exam from a much deeper pool, and a lot of the test's wrong-answer distractors are designed to catch you on numbers you "kind of" remember — 4/32 vs 2/32, 100 vs 125 psi, 20–45 vs 55 psi. The only way to lock those in is to drill the full question pool and read the handbook section that backs every answer.

That's what the California CDL Master Guide is built for: 206 pages walking through every testable concept in the 2026 handbook with memory tricks, plus a 200-question master test at the back that mirrors the real DMV question style across General Knowledge, Air Brakes, and Combination Vehicles. Every answer is cited to the handbook so you can verify it yourself.

OK — back to the test.

Section 2 — Air Brakes (15 questions)

26. Why must air tanks be drained?

1. To reduce vehicle weight
2. To remove water and compressor oil that can damage valves and freeze in winter
3. To check tank capacity
4. Air tanks should not be drained

27. The drain valve on an air tank is located:

1. On the top of the tank
2. On the side of the tank
3. On the bottom of the tank
4. Inside the compressor housing

28. Typical air compressor governor cut-out pressure is approximately:

1. 60–80 psi
2. 100 psi
3. 120–140 psi
4. 150 psi

29. The low air pressure warning device must activate before air pressure in either system drops below:

1. 30 psi
2. 45 psi
3. 55 psi
4. 75 psi

30. For dual air systems, air pressure should build from approximately 85 to 100 psi within:

1. 15 seconds
2. 30 seconds
3. 45 seconds
4. 90 seconds

31. On a tractor-trailer combination vehicle, the tractor protection valve and parking brake valve should close (pop out) when air pressure drops into what range?

1. 5–15 psi
2. 20–45 psi
3. 55–75 psi
4. 100–120 psi

32. Maximum air loss for a single vehicle in the static leakage test (1 minute, engine off, brakes released) is:

1. 1 psi
2. 2 psi
3. 3 psi
4. 5 psi

33. Maximum air loss for a combination of two vehicles in the static leakage test is:

1. 2 psi
2. 3 psi
3. 4 psi
4. 6 psi

34. In the applied leakage test (engine off, brake fully applied for 1 minute), maximum allowable loss for a single vehicle is:

1. 2 psi
2. 3 psi
3. 4 psi
4. 6 psi

35. In the applied leakage test for a combination of two vehicles, the maximum allowable air loss is:

1. 2 psi
2. 3 psi
3. 4 psi
4. 6 psi

36. Brake drums (or discs) must not have cracks longer than:

1. 1/8 the width of the friction area
2. 1/4 the width of the friction area
3. 1/2 the width of the friction area
4. The full width — drums are designed to crack

37. Brake linings (friction material) must not be worn thinner than:

1. 1/8 inch
2. 1/4 inch
3. 1/2 inch
4. 1 inch

38. ABS (Anti-lock Braking System) on a CMV:

1. Always shortens stopping distance significantly
2. Does not necessarily shorten stopping distance but helps you keep control during hard braking
3. Allows you to brake harder without consequence
4. Replaces the need for service brake checks

39. Spring brakes are part of which brake system(s)?

1. Service brakes only
2. Parking brakes only
3. Parking and emergency brake systems
4. Service, parking, and emergency brake systems

40. The one-way check valve on an air brake system is required by California law (CVC §26507) to be located:

1. Between the compressor and the first air reservoir
2. Between each axle's brake chamber
3. Inside the foot valve
4. CVC §26507 requires no such valve

Section 3 — Combination Vehicles (10 questions)

41. On a combination vehicle, the emergency air line (supply line) glad-hand is typically color-coded:

1. Blue
2. Yellow
3. Red
4. Green

42. The service air line (control line) glad-hand is typically color-coded:

1. Blue
2. Yellow
3. Red
4. Black

43. The trailer hand valve (also called the trolley valve or Johnson bar) should be used:

1. As your primary brake while driving
2. Only to test the trailer brakes — never as your primary brake in normal driving
3. To park the trailer overnight
4. Only in emergencies, never to test

44. When coupling a tractor to a semitrailer, after you back under and the kingpin appears to lock, you must perform the:

1. Air brake test
2. Tug test — pull gently forward with trailer brakes locked to confirm the coupling
3. Light test
4. Cargo securement check

45. Before you back the tractor under the trailer, the tractor should be positioned:

1. Directly in front of the trailer (never back at an angle)
2. At a 45-degree angle to the trailer
3. Anywhere within 10 feet — angle does not matter
4. With the back of the tractor touching the landing gear

46. According to the handbook, the two most important things to prevent a rollover in a combination vehicle are:

1. Drive faster on turns and lock the brakes
2. Keep cargo as close to the ground as possible, and drive slowly around turns
3. Empty the trailer before any curve
4. Always use the trailer hand brake on curves

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

1. In the same direction you want the trailer to go
2. In the opposite direction of where you want the trailer to go
3. Straight — the trailer follows
4. Toward whichever mirror shows more space

48. The trailer air supply valve (red 8-sided knob in the cab) is pulled out to:

1. Supply air to the trailer
2. Shut air off and put on the trailer's emergency brakes
3. Engage cruise control
4. Charge the secondary system

49. The phenomenon where the rear wheels of a long vehicle follow a tighter path than the front wheels through a turn is called:

1. Jackknifing
2. Hydroplaning
3. Off-tracking (cheating)
4. Crack-the-whip

50. If you cross the air lines while coupling (service connected to emergency, emergency to service), what happens when you push the trailer air supply knob in?

1. Nothing — the truck won't move
2. The trailer spring brakes will not release because no supply air reaches the trailer tanks
3. The brake lights stay on
4. The compressor shuts down automatically

Answer key with handbook citations

How to score yourself

The hardest questions for most people aren't the obvious safety ones — they're the specific numeric thresholds. 2/32 vs 4/32. 100/125/150 psi ladder. 20–45 psi spring brake pop-out vs 55 psi low-air warning. The DMV writes distractors that look almost right. Locking the exact numbers in your head is the difference between an 88% and a 76%.

Bottom line

The California CDL written exams are passable on the first try if you (1) study the right handbook (2026 DL 650, not federal or another state's), (2) drill numbers until they're automatic, and (3) practice on questions that mirror the DMV's actual style. Generic free practice tests can get you started — what they can't do is cover the full question pool with handbook-cited explanations, which is what closes the 70%→90% gap.

When you're ready to go from "I think I'll pass" to "I know I'll pass," grab the California CDL Master Guide — 206 pages of plain-English coverage of every testable concept in the 2026 handbook, plus a 200-question master test that mirrors the DMV's question style across General Knowledge, Air Brakes, and Combination Vehicles. $39, 30-day refund, every answer cited so you can verify it against the handbook yourself. Pass on your first try or get your money back. That's the deal.