All drivers of Commercial Motor Vehicles (CMVs) in the United States must possess a Commercial Driver’s License (CDL). To acquire this specialized license, you must first pass a series of written knowledge tests and earn your Commercial Learner’s Permit (CLP). The tests are designed to determine if you possess the knowledge to safely operate a commercial vehicle. You will have to take one or more knowledge tests, depending on what class of license and what endorsements you need. You will need to answer at least 80% of the questions correctly to pass. The knowledge tests are written tests that must be taken in your home state. Contact your local Motor Vehicle Department for information regarding location, associated fees, time allotment, and date of each knowledge test. Details will vary from state to state.