Sidewalks constructed to current standards shall be required along the street frontage of all building sites submitted to the Architectural Commission for review. Where a building site fronts an unimproved street or is in an individual subdivision, the requirement may be waived if adjacent property does not have existing sidewalks. All proposed building sites, including single-family residences, along arterial streets shall have sidewalks. Industrial parks are not required to have sidewalks, except along arterial streets.