To drive a commercial vehicle across state lines, a driver must be at least: Do you currently have car insurance? Insurance is mandatory to drive in Ohio Yes I have insurance. But please show me your best quotes. No, please help me find the best insurance. Question To drive a commercial vehicle across state lines, a driver must be at least: Answers 15 years old. 18 years old. 21 years old. 25 years old. Explanation A driver must be at least 21 years old to be licensed to drive a CMV across state lines.