Md. Code, Transportation § 21–1207.2

(a) An individual under the age of 16 years may not ride on a scooter or on in–line skates on any highway, bicycle way, sidewalk, or other property open to the public or used by the public for pedestrian or vehicular traffic, unless the individual is wearing a helmet that meets or exceeds the standards of the American National Standards Institute, the Snell Memorial Foundation, or the American Society for Testing and Materials for protective headgear for use in bicycling or in–line skating.

(b) This section shall be enforced by the issuance of a warning that informs the offender of the requirements of this section and provides educational materials about helmet use.