SUSTAINABILITY AND URBAN DENSITY

misbe2011 Tracking Number 203

SUSTAINABILITY AND URBAN DENSITY A decision based design approach This is a blind reviewed conference. No names or affiliation. Keywords: Sustainability, built environment, urban density, urban design and decision making ABSTRACT This paper concerns the definition, construction and application of a decision based design model which abeles the integration of the allocation of a variety of urban land uses with the distribution of different urban densities, in particular of residential urban areas. Urban planning is, among others things about the spatial distribution of human activities and their physical facilities like buildings, roads, green areas etc. in amount, place and time over a well-defined area. Today, sustainable urban development and sustainability in urban areas are important issues in urban planning. The aspects related to these issues have to be taken in account when developing urban areas. One of these aspects is urban density. Nowadays, it is generally assumed (and accepted) that urban density is related to sustainability. New urban planning approaches, loosely based around new urbanism, are successfully reducing environmental impacts by altering the built environment to create and preserve sustainable cities which support sustainable transport. Residents in compact urban neighborhoods drive fewer miles, and have significantly lower environmental impacts across a range of measures, compared with those living in sprawling suburbs. Urban density can be expressed in many ways. A widely used measurement is the number of dwelling units per unit area (acre, hectare). This measurement gives only information about the number of dwellings, not about their size or the way they are grouped. More general and precise ways of measuring density are measurements based on built area or gross floor area, respectively named ground space index and floor space index. Using these measurements in urban design processes cannot guarantee a good or bad urban area because they are only measurements about the ratio of built and non-built spaces and give no information about the activities and functions within these spaces, neither about their distribution. Therefore, the outcome of an urban design model based on only density factors (as the amounts of built and non-built areas) gives no information about contents of these spaces. Consequently, these types of models are not applicable in a context of social oriented decision making, as in urban planning. As stated above, this paper is about the integration of an urban function or urban activity based model and urban density based model. The first part will give an overview of the definitions, differences and similarities of both function based and density based models, as well as definitions of the combined model. The second part describes the application of the combined model in a number of tests, including a final conclusion.