California CDL General Knowledge Test
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ExploreAbout this exam
A California commercial driver's license (CDL) is the credential that lets you legally operate a commercial motor vehicle - generally a single vehicle rated 26,001 pounds or more, a combination rated 26,001 pounds or more, a vehicle built for more than ten passengers including the driver, a vehicle towing a trailer rated 10,001 pounds or more, a placarded hazardous materials vehicle, or a 3-axle vehicle weighing more than 6,000 pounds. Before the skills test, applicants must hold a commercial learner's permit (CLP) for at least 14 days, and the CLP itself is issued only after the required knowledge test or tests are passed. Those knowledge tests measure your understanding of the rules of the road and how to safely operate a CMV, and the DMV points candidates to the California Commercial Driver Handbook and its sample knowledge tests as preparation. This page is an independent study resource: it is not affiliated with, endorsed by, or operated by the California DMV, and the DMV's own publications and office staff are the final authority on requirements, eligibility, and scoring.
What you'll study
About California CDL General Knowledge Test preparation
How many questions are on the California CDL General Knowledge Test, and what score do I need to pass?
The DMV's CDL page does not publish a question count or a passing percentage for the general knowledge test. Because the exam is drawn from the California Commercial Driver Handbook, study every chapter rather than targeting a question count, and confirm current scoring details with the DMV or your test examiner.
How many times can I fail a knowledge test before something happens?
You get three attempts to pass each required knowledge test. If you fail the same test three times, your application is no longer valid and you must reapply, which means starting the application process over. Plan your study time so you are not spending attempts to learn the material.
How long is my CDL application good for?
The nonrefundable application fee and application are valid for 12 months. If you do not meet all CDL requirements - including passing both the knowledge test and the skills test - within 12 months of applying, the application expires and you must reapply.
Can I squeeze in a knowledge test right before the office closes?
No. To allow sufficient testing time, the DMV does not administer knowledge tests within 30 minutes of closing. Arrive with enough margin that you are seated and checked in well before that cutoff, especially on your first visit when identity and residency documents are also reviewed.
How soon can I take the skills test, and what happens if I fail part of it?
You must hold a CLP for at least 14 days before applying for the skills test, and skills tests are by appointment only. You have three tries, a retest fee applies each time, and failing any part of the skills test postpones all other testing.
Do I need Entry Level Driver Training before I test?
ELDT from a registered training provider is required for an original Class A or Class B CDL, an upgrade from Class B to Class A, and first-time School Bus, Passenger, or Hazardous Materials endorsements. California also requires 15 hours of behind-the-wheel training certified on the DL 1236 before an original Class A or B CDL is issued.
What if my Drug and Alcohol Clearinghouse status is 'prohibited'?
The DMV cannot issue, replace, renew, transfer, or upgrade a CDL or CLP for a driver with a prohibited DACH status, and it must remove commercial driving privileges until the return-to-duty process is complete. You may renew no earlier than 24 hours after your status shows 'not prohibited.'
How long until my actual CDL card arrives?
After you pass the skills test, surrender an out-of-state CDL, or submit your certificate, the DMV issues an interim CDL valid for 60 days. If your official CDL has not arrived after 45 days, call the DMV at 1-800-777-0133 to check the status.
What is the most common reason candidates lose attempts?
Underestimating the breadth of the material. The general knowledge test draws on rules of the road, safe operating practices, inspection, cargo, and emergency handling, and the same handbook feeds the endorsement tests. Work through the handbook chapter by chapter, then use the DMV's sample knowledge tests to find weak areas before you sit for the real one.