Question To obtain a passenger endorsement, applicants must be at least: Answers 15 years old. 18 years old. 21 years old. 25 years old. Explanation You must be at least 18 years old to obtain a CDL. However, you must be 21 years old to drive in interstate commerce or to obtain a passenger or hazardous materials endorsement. This questions appears in the following tests: New Jersey Class B Knowledge Test