A Planned Development (PD) is not a zone, but a special approach to land development applied to achieve the basic objectives of good zoning practices. The use of this approach is intended to permit a greater degree of flexibility in the site planning and design of structures in situations where modification of specific provisions of this title will not be contrary to the intent and purpose of the zone and will not be harmful to the neighborhood in which the development occurs. In addition, it is intended to achieve land economics in development, maintenance, street systems and utility networks, while allowing for the grouping of buildings for privacy, usable and attractive open spaces, safe circulation and general well being of the inhabitants. A further purpose of a PD is to allow for mixed uses when in conformance with the Comprehensive Plan.