; (C) a special purpose district (including a park district); (D) an Indian Tribe that represents or otherwise serves an urban area or a rural area; or (E) a metropolitan planning organization (as defined in section 134(b) of title 23, United States Code). (3) Program The term program means the Transit to Trails Grant Program established under subsection (b)(1). (4) Rural area The term rural area means a community that is not an urban area. (5) Secretary The term Secretary means the Secretary of Transportation. (6) Transportation connector (A) In general The term transportation connector means a system that— (i) connects 2 ZIP Codes or communities within a 175-mile radius of a designated service area; and (ii) offers rides available to the public. (B) Inclusions The term transportation connector includes microtransits, bus lines, bus rails, light rail, rapid transits, or personal rapid transits. (7) Urban area The term urban area means a community that— (A) is densely developed; (B) has residential, commercial, and other nonresidential areas; and (C) (i) is an urbanized area with a population of 50,000 or more; or (ii) is an urban cluster with a population of— (I) not less than 2,500; and (II) not more than 50,000. (b) Grant program (1) Establishment The Secretary shall establish a grant program, to be known as the Transit to Trails Grant Program , under which the Secretary shall award grants to eligible entities for— (A) projects that develop transportation connectors or routes in or serving, and related education materials for, critically underserved communities to increase access and mobility to Federal or non-Federal public land, waters, parkland, or monuments