A typology of rules : predictability, flexibility, and adaptation in form-based codes

Form-based codes have been touted as a more flexible approach to zoning that emphasize physical form over land use to create more predictable built results, making sustainable urban form more achievable. However, scholarship to date has focused primarily on the New Urbanist aspects of form-based codes, with limited attention paid to broader issues of urban design and development as they relate to codes themselves. This paper thus proposes a new framework for studying form-based codes: a typology of rules. This proposed framework provides an instrument for evaluating form-based codes by looking at the structural characteristics of codes as they relate to predictability, flexibility, and adaptation to future change. It also separates the study of form-based codes from battles over New Urbanism, instead reframing form-based codes as an autonomous field of inquiry. Use of this typological analysis in a series of case studies indicates that there is a lack of diversity in the rule typologies currently employed in form-based codes. A discussion then highlights how the use of a typology of rules could help create codes that are adaptive and flexible enough to respond to the needs of contemporary urbanism.