Knowledge test: CDL

The knowledge test is given in 4 languages: English, Spanish, Russian, and Serbian–Croatian. Interpreters are not allowed

You may take the knowledge test at any CDL/CLP office location that offers testing. Test scores are valid for 1 year from the date the test was passed.

The CDL general knowledge test is not required when upgrading to another class or adding endorsements.

Only a knowledge test is required if upgrading with hazmat, double/triple, or tanker endorsements.

You must pass the knowledge test:

  • Before you can take the skills test.
  • Any time you update your CDL by:
    • Upgrading the class of vehicle.
    • Adding any special endorsements.
    • When transferring or renewing CDL with hazmat endorsement. See special endorsement for other hazmat requirements.
  • To remove the air brake restriction.
  • To reinstate your CDL after 1 year (or more) without holding a CDL.

How to prepare

  • Study the Commercial driver guide to prepare for the test. The guide is only available in English and contains all the information you’ll need to pass the test. In the first chapter you will find a table titled “What sections should you study?”. This table marks which section you should study in the guide for the class of vehicle and or endorsements you are testing for.
  • You may also take the practice test for a sample of the types of questions that will be on the test.

Penalties for trying to get a CDL fraudulently could include:

  • Cancellation of your driver license.
  • Having to wait up to 1 year before you can reapply for a CDL.

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