Agenda - Planning Commission - 01/31/2013 - Special

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clear numerical values, allowing planners and officials to focus on concrete variables instead of wrangling with vague, contextual ideas such as "quality of life." The citizens of Iowa City, along with countless other cities, would likely agree that their concern is one of community character and compatibility and not solely focused on the number of dwelling units or type of ownership involved. Concerns surrounding traffic, parking, infrastructure, and more are legitimate matters in any proposed develop- ment. Nuisance concerns are also prominent and absolutely real. But from all these issues, the central phenomenon that motivates citizens to demand change (and planners to alter their zoning ordinances) is the threat of development that is incompatible to the area. SOLUTIONS FOR INCOMPATIBLE DEVELOPMENT For a zoning ordinance to better address in- compatible development, the first step is to define the existing character of a given area. For example, Columbia, Tennessee, recently wrote a new zoning ordinance in which all districts are first described by their actual physical form and intensity of use (i.e., level of noise, traffic, hours of operation, etc.). Built from the framework of the rural -to - urban transect, this new set of zoning dis- tricts focuses on the physical characteristics that make each environment unique. Each element is selected based on the ability to measure them in exact detail. For example, while a suburban neighborhood might be "quiet" and "safe," the elements that dic- tate the actual character are form based and include components such as the following: • Setbacks • Yard types (presence of front, rear, or side yards) • Building Height • Block Length • Lot Coverage • Frontage Type • Facade to Lot Frontage Ratio These measures, which are increasingly common in contemporary zoning ordinances, provide clear, measureable information on the physical traits of any given area. As Dan Parolek, coauthor of the book Form -Based Codes, describes, the combination of these numbers constitute the "DNA" of a particular place. Each value is established by measur- ing the existing features of each zone or "transect." For example, the lot coverage of an urban zone is established by defining the actual lot coverage of the area that will be emulated. This is a critical aspect of form - based standards. The values are not based on vague concepts or arbitrary desires about what looks good. They are instead rooted in plain, detailed numbers based on the ideal environment that the city wants to replicate. These measures include no mention of density. However, density is impacted, and often controlled, by each of these factors. To extend Parolek's metaphor, our own human DNA doesn't dictate our adult height, but it certainly determines our potential growth. Likewise, the built environment's DNA doesn't dictate density but certainly establishes the absolute potential. Peter Katz and Steve Price This notion may seem faulty at first glance. A collection of form -based elements governing setbacks, lot coverage, and build- ing height may not appear to impact density at all, particularly when compared to the ultimate regulation for density potential: the common maximum density standard. Zoning ordinances typically do a terrific job of de- fining the absolute potential for density by stating that no more than, say, four units per acre may be developed in a given district. But density aside, what else is known or assured with the future development? The land use is likely restricted, but is there any other regulation that will ensure that the right form of development takes place? For example, if a development is to be single-family residential with a density of four units per acre, it is no exaggeration that a common zoning ordinance would then allow a plain building devoid of any architectural features to be developed so long as it complied with building codes and setbacks. This building would likely be incompatible with the defined character of the area. After all, most single-family residential areas are identified not by the families who live there but by the unique buildings they oc- cupy. These buildings commonly have pitched roofs, front porches, facade widths around 3o to 4o feet, building heights of 25 to 3o feet, side driveways, and rear parking. Variations certainly exist between each individual house How Zoning Defines a One -Block Parcel Density, use, floor -are ratio, setbacks, parking requirements, and maximum building heights specified How Guidelines Define a One -Block Parcel Density, use, floor - are ratio, setbacks, parking requirements, maximum building heights, frequency of openings, surface articulation, and landscaping specified How a Regulating Plan and Codes Define a One -Block Parcel Street and building types, build -to lines, floor - to -floor heights, and percent of site frontage specified but, on the whole, buildings in a neighbor- hood possess some version of these aesthetic features in a consistent manner. And when one building along the street happens to lack these features, surrounding residents naturally be- come concerned since the physical character of the area is no longer maintained. In short, it is the lack of these physical features that creates the visual cue that something is amiss. From that initial discovery, discussion often leads to questions about density or land use, but those are secondary to the issue of compatibility. Without form -based regulations, den- sity standards cannot ensure compatible development. The Iowa City case shows firsthand that a request can meet the zoning ZONINGPRACTICE 11.12 AMERICAN PLANNING ASSOCIATION I page 4