PUDs explained. In certain situations, a planned unit development is a more appropriate development type. In general, planned unit developments are utilized when a proposed project does not appropriately fit into traditional or conventional zoning. For example, if a developer wants to build a residential development that includes several types of housing within that development (e.g., single-family homes with townhomes and multi-unit buildings), then a PUD would be the best option for development. Another example for PUDs includes a mixed-use development, such as a "lifestyle center." This would include several different land uses contained within the same site. PUDs are also used when there are constraints to development on a site. These constraints can include wetlands, heavily wooded areas, topography issues, and other challenges. As such, it may be appropriate to build a development with reduced lot sizes, lot widths, setbacks, or other features that are otherwise required by the underlying zoning district. PUDs are its own zoning classification. The image below shows an example of a mixed-use PUD layout.