Official sources

CDL Test Prep is not a government website. CDL Test Prep is an independent study site and is not affiliated with any DMV, state agency or the FMCSA. We do not issue permits, licenses or test appointments. Our questions and explanations are our own, written from the official documents below. For anything official, such as rules, fees, test formats or appointments, use these sources and your state’s motor vehicle agency.

Federal CDL rules

• Commercial Driver’s License Program Federal Motor Carrier Safety Administration (FMCSA) Federal CDL program: who needs a CDL and how to get one from your state.
• 49 CFR Part 383, Commercial Driver’s License Standards Electronic Code of Federal Regulations (eCFR) The federal rules for CDL classes, endorsements, knowledge tests and skills tests.
• 49 CFR 383.135, Passing knowledge and skills tests Electronic Code of Federal Regulations (eCFR) Sets the passing score: at least 80% correct on each CDL knowledge test.

CDL manuals our CDL tests are written from

Each state publishes its own edition of the same model CDL manual. Our CDL practice tests cite the newest edition below and are checked against the others.

• Commercial Driver's License Manual (PDF), Version 07/20/2026 (form DMV 60A) Virginia DMV edition Manual page on the issuer’s website, where the current edition is posted.
• Commercial Driver's License Manual (PDF), Version March 2025 (document T20964 Rev. 1025) Massachusetts RMV edition
• Commercial Driver's License Manual (PDF), Version September 9, 2022 Indiana BMV edition
• CDL Knowledge Exams Virginia Department of Motor Vehicles How Virginia gives the CDL knowledge exams.

Driver handbooks our permit and road signs tests are written from

• California Driver's Handbook (PDF), DL 600 English, rev. 6/2025 California Department of Motor Vehicles Handbook page on the issuer’s website. Used under the CC BY-NC 4.0 license.

Road sign standard

• Manual on Uniform Traffic Control Devices (MUTCD) Federal Highway Administration (FHWA) The national standard for road signs, signals and pavement markings. The sign drawings on our road signs practice test follow its standard designs.

Find your state’s DMV

You take the knowledge test at your state’s motor vehicle agency, which also publishes your state’s current manual and test rules.

• State motor vehicle services USAGov Links to the motor vehicle agency (DMV) of every state, where you take the test.

If something differs

Laws and manuals change. If anything on CDL Test Prep differs from an official source, the official source is right. Please tell us through our contact page so we can fix it. More in our disclaimer.