A street or alley lying along the boundary of a subdivision may be dedicated less than the full required width, but in no case less than one-half the required width, if it is practical to require the dedication of the remaining width when the adjoining property is subdivided. Such portion of a street shall be distinctly designated upon the map or plat as being a portion only of a street, and not the street in full width. (Ord. 3153 § 2 (Exh. C), 2010; Ord. 2100 § 1, 1985; Ord. 1369, 1971; prior code § 28.1103(5)).