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California CDL Knowledge Practice Test

In California, you take the CDL knowledge tests at the DMV to get a commercial learner permit (CLP). Here is what the California DMV says about the process and how to practice for the tests.

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How the knowledge tests work

You apply online, then visit a DMV office to finish your application, pass the knowledge tests and get your CLP. You have three attempts to pass each required test. If you fail the same test three times, your application is no longer valid and you must reapply. The application and fee are good for 12 months. Federal rules require 80% correct on each knowledge test.

After you pass

Your CLP is valid for up to 180 days and can be renewed once, as long as that is within one year of your application. You must hold the CLP 14 days before the skills test, which covers vehicle inspection, basic control skills and a road test.

Training rules in California

Federal entry-level driver training (ELDT) is required for a first Class A or B CDL, an upgrade from B to A, and a first S, P or H endorsement. California also requires at least 15 hours of behind-the-wheel training for an original Class A or B, proven with form DL 1236.

How passMarker helps

Practice General Knowledge, Air Brakes, Combination and each endorsement topic from the California commercial driver handbook, with explanations for every answer. Start with the free diagnostic.

Original sample practice questions

Study examples from the learner-approved practice bank. These are not live exam questions. Open each answer to see the explanation and source reference.

1. Before beginning a delivery, a driver reviews the prior vehicle inspection report and finds a safety-related defect listed. What should the driver verify before operating the vehicle?

  1. The maintenance staff has released the vehicle for service and the defect was repaired or determined unnecessary
  2. The vehicle has enough fuel for the planned route
  3. The cargo is loaded before asking about the report
  4. The defect is noted again at the end of the trip
Show answer and explanation

Answer A. The driver should review the previous report and ensure the vehicle was released for service. Safety-related report items must be repaired or certified as unnecessary.

Source: DL 650 REV. 12/2019, Section 2, PDF pp. 37–44

2. During a pre-trip inspection, a driver finds that the air compressor has its own oil supply. What should the driver do before driving?

  1. Test the stop light switch by releasing the brakes
  2. Drain the brake drums
  3. Check the compressor oil level
  4. Push in the parking brake control
Show answer and explanation

Answer C. If the air compressor has its own oil supply, the handbook says to check the oil level before driving.

Source: DL 650 REV. 12/2019, Section 5, PDF pp. 101–105

3. A driver is loading a combination vehicle for a route with several tight ramps. Which loading approach best reduces rollover risk?

  1. Place the heaviest cargo high and toward the rear for easier steering
  2. Concentrate cargo near the front of the trailer regardless of height
  3. Keep the cargo low, centered, and spread out as much as possible
  4. Load most cargo along one side to leave more aisle space
Show answer and explanation

Answer C. Keeping cargo close to the ground, centered, and spread out helps reduce rollover risk.

Source: DL 650 REV. 12/2019, Section 6, PDF pp. 115–120

4. During a pre-trip inspection of a tank vehicle, which condition should receive the highest priority?

  1. Signs of liquid or gas leaking under or around the vehicle
  2. Minor dirt on the exterior tank shell
  3. A faded company logo on the tank
  4. Road dust on the wheel rims
Show answer and explanation

Answer A. The excerpt identifies leaks as the most important item to check on all tank vehicles.

Source: DL 650 REV. 12/2019, Section 8, PDF pp. 139–140

5. Before accepting a hazardous-material shipment, a carrier employee notices that the package markings do not match the shipping description. What should the carrier do?

  1. Refuse the improper shipment
  2. Ask the driver to create new shipping papers
  3. Transport it only during daylight hours
  4. Remove the package labels before departure
Show answer and explanation

Answer A. The carrier checks that the shipper correctly described, marked, labeled, and otherwise prepared the shipment before transportation, and refuses improper shipments.

Source: DL 650 REV. 12/2019, Section 9, PDF pp. 143–151

6. Before beginning a route, a bus driver finds that the previous driver reported a defect. What should the driver do before signing the previous driver’s inspection report?

  1. Wait until the end of the route to determine whether the defect affects safety
  2. Sign the report only after passengers have boarded
  3. Verify that the reported defect was certified as repaired or that repairs were not needed
  4. Sign the report if the bus starts and the parking brake holds
Show answer and explanation

Answer C. The driver should sign the previous driver’s report only when earlier defects have been certified as repaired or repairs were not needed.

Source: DL 650 REV. 12/2019, Section 4, PDF pp. 95–97

7. Before beginning a route, a school bus driver finds that one outside mirror does not provide the widest practical view of the danger zone. What should the driver do?

  1. Rely on the overhead inside rearview mirror instead
  2. Begin the route and adjust the mirror at the next stop
  3. Use only direct vision to check the affected side
  4. Have the mirror adjusted before operating the bus
Show answer and explanation

Answer D. All mirrors should be checked before operating the bus to obtain the maximum viewing area; mirrors should be adjusted if necessary.

Source: DL 650 REV. 12/2019, Section 10, PDF pp. 169–175

8. While pulling doubles, a driver approaches an exit ramp with a curve that could be handled at a higher speed by a straight truck. What is the safest approach?

  1. Maintain the straight-truck speed and brake only if the trailer leans
  2. Slow down and steer gently through the curve
  3. Accelerate through the curve so the trailers track behind the tractor
  4. Steer sharply at the start of the ramp to keep the trailers aligned
Show answer and explanation

Answer B. A curve speed that is safe for a straight truck or single trailer may be too fast for doubles. Go slowly and steer gently to help prevent rollover.

Source: DL 650 REV. 12/2019, Section 7, PDF pp. 133–135

9. During an in-vehicle inspection, a driver sees that the left-turn dashboard indicator illuminates when the vehicle starts. What additional inspection is still required for the actual left-turn signal function?

  1. Inspect the signal only if the vehicle has a trailer attached
  2. Wait to inspect the signal until after driving at highway speed
  3. Assume the exterior signal works because the dashboard indicator illuminated
  4. Check the actual turn-signal operation during the lights operation inspection
Show answer and explanation

Answer D. Dashboard indicators are checked at startup, but operational inspection of the actual turn signals is done separately during the lights operation inspection.

Source: California modernized CDL supplement, Section 11M (modernized inspection), PDF pp. 3–5

10. Before beginning a trip with a loaded cargo vehicle, what should the driver verify as part of the vehicle inspection?

  1. The cargo is arranged only for the quickest unloading
  2. The cargo is covered by a sealed document
  3. The cargo is placed as high as possible
  4. The cargo is balanced and properly secured
Show answer and explanation

Answer D. As part of the vehicle inspection, the driver should make sure the vehicle is not overloaded and that cargo is balanced and secured properly.

Source: DL 650 REV. 12/2019, Section 3, PDF pp. 89–91

Frequently asked questions

How many tries do I get on the California CDL test?

Three attempts for each required knowledge test.

What score do I need to pass?

80% on each knowledge test, the federal standard in 49 CFR 383.135.

How long is a California CLP good for?

Up to 180 days, renewable once if within one year of applying.

Do I need training before the skills test?

Yes for a first Class A or B: federal ELDT plus California's 15 hours of behind-the-wheel training.

Official sources

Source information reviewed November 11, 2026. Policies can change; confirm requirements with the licensing agency before booking.

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