 Alexandria, Virginia, in 1952, as an amendment to its city code, provided for a "Community Unit Plan", with the intent to provide for planned community facilities and open space development with new residential building.One of the first modern uses of the term "planned unit development" appears in San Francisco's code of ordinances in 1962.PUD as a regulatory process is a means of land regulation which promotes large scale, unified land development by means of mid-range, realistic programs in chase of physically curable, social and economic deficiencies in land and cityscapes.