In this Part IV of this subtitle, “police officer” means: any uniformed police officer; or any civilian employee of the Department of State Police or of the Maryland Transportation Authority Police Force assigned to enforce this Part IV of this subtitle or any rule or regulation adopted under this Part IV of this subtitle, but only while acting under written authorization of the Secretary of State Police. Subject to the provisions of paragraph (2) of this subsection, any police officer shall have the authority to enforce this Part IV of this subtitle and any rule or regulation adopted under it. A civilian employee of the Maryland Transportation Authority Police Force shall have the authority stated in paragraph (1) of this subsection only if the individual is: acting under the immediate direction and control of a uniformed police officer; and certified by the Department of State Police to enforce this Part IV of this subtitle and any rule or regulation adopted under it.