The requirements of this title as to minimum site development standards shall not be construed to prevent a use as permitted in a respective zone or any parcel of land in the event such parcel was held in separate ownership prior to the initial enactment of this title. Each such parcel to be developed must have not less than sixteen (16) feet of frontage on a street and the density of the development may not exceed that permitted by area requirements in the respective zone. (PZSC § 03-11-002)