The uniform width of thirteen feet (13') on all streets and avenues approximately eighty feet (80') wide, and twelve feet (12') on all streets and avenues approximately seventy feet (70') wide, or less, measured from the front line of the lots at right angles with said line toward the center of the street or avenue, shall be, and the same is hereby set off and reserved for sidewalk purposes. (1974 Code § 6-104)