Maryland Code, Transportation § 21-1127

(a) An individual may not operate for hire a motor vehicle designed to carry 15 or fewer passengers, including the driver, unless the individual holds a valid for-hire driver's license or transportation network operator's license issued by the Public Service Commission or the appropriate local authority.

(b) A person may not allow an individual to operate for hire a motor vehicle designed to carry 15 or fewer passengers, including the driver, unless the individual operating the motor vehicle holds a valid for-hire driver's license or transportation network operator's license issued by the Public Service Commission or the appropriate local authority.

(c) A person convicted of a violation of this section is subject to imprisonment not exceeding 1 year or a fine not exceeding $1,000 or both.