Known by several terms, including tiers, development policy areas are typically designated to maintain and/or redevelop existing urbanized areas, continue urbanization in developing areas, reserve land for future urbanization, and preserve land for open space, agricultural production, or environmental protection. Policy areas then provide a framework for other planning and zoning requirements. The standard version delineates an “urban” area of established neighborhoods and centers, “urbanizing” areas where most new development will take place, and an “urban reserve” area where open space is preserved until some future date. Source/Reference: Porter, 1997, pp. 44; Porter, 1996, pp. 8.