What’s this about?
The Built Environment & Health (BEH) project is an interdisciplinary program of research at Columbia University. Led by epidemiologist Andrew Rundle, BEH uses spatial data to examine the implications of the built environment, including land use, public transit, and housing, for physical activity, diet, obesity, and other aspects of health. With a focus on New York City, BEH research will inform public policy to promote health in the city and metropolitan area. BEH is affiliated with the Robert Wood Johnson Foundation Health & Society Scholars program at Columbia.
Observational coding of Urban Design in New York City
With funding from the Robert Wood Johnson Foundation’s Active Living Research (ALR) program, the BEH group is using observational measures of urban design to validate digital measures that can be developed city-wide. If these measures appear valid, they will be introduced into analyses that examine the association between the built environment and physical activity or obesity.
For the first phase of this project, our field staff coded five dimensions of urban design—imageability, enclosure, human scale, transparency, and complexity—for nearly 600 block faces in New York City. This project required the translation of perceptual and abstract concepts into concrete, distinct decision rules. Our decision rules are drawn form a recent ALR-funded project on Urban Design Qualities Related to Walkability led by Reid Ewing at the University of Maryland. Ewing’s team developed detailed observational protocols for the following dimensions of urban design:
Imageability refers to the quality of a place that makes it distinct, recognizable, and memorable. Elements that contribute to an “imageable” street include parks, plaza, and courtyards, features that incorporate the natural environment, historic buildings, signs or indicators of the functions taking place within buildings, buildings with non-rectangular shapes, sidewalk dining, pedestrian traffic, and a minimal loud noise.
Enclosure represents the degree to which streets and other public spaces are visually defined by buildings, walls, trees, and other vertical elements. Features such as buildings that front the sidewalk, blocked sight lines, and limited vertical views of the sky contribute to higher ratings of this urban design quality.
Human scale is the orientation of a streetscape in which the size, texture, and articulation of physical elements matches the size and proportions of humans and, equally important, corresponds to the speed at which humans walk. Streets with a lot of vertical open space, sight lines that extend far into the distance, and very tall buildings are not at a human scale, while streets with shorter buildings, windows at street level, small planters, and street furniture are more likely to be associated with high ratings on this dimension.
Transparency is the degree to which people can see or perceive what lies beyond the edge of a sidewalk/path or public space and, more specifically, the degree to which people can see or perceive human activity beyond the edge of a street or other public space. The elements that contribute to higher levels of transparency (as rated by urban designers) are a high proportion of windows on the ground floor, building facades that are close to the sidewalk edge, and building uses that are active and associated with foot traffic into and out of the building.
Complexity refers to the visual richness of a place that depends on the variety of the physical environment, specifically the numbers and kinds of buildings, architectural diversity and ornamentation, landscape elements, street furniture, signage, and human activity. More buildings, a variety of building colors, outdoor dining, displays of public art, and the presence of pedestrians are associated with higher rankings of this dimension by urban design experts.
To select the New York City block faces for this study, we constructed a sampling frame from the Primary Land Use Tax Lot Output (PLUTO) data available from the Department of City Planning. Census blocks were categorized into a 2 x 3 table based on their aggregated scores on two variables: ratio of total floor area to parcel area (divided at the median) and proportion of floor area coded as residential (tertiled), and drew a sample of 100 census blocks from each stratum.
Six coders worked on this project over the summer of 2006. They spent two days training, using video clips from Ewing’s group as well as our own field manual (pdf) and other materials. Interclass correlation (ICC) scores for consistency and agreement among the coders were high (.69 or above) for all dimensions except human scale. (One component of human scale, street furniture, proved difficult to measure reliably and brought down the average ICC ratings.)
Summary scores for all 5 urban design qualities were extrapolated across the entire city and mapped (jpeg). Overall, Manhattan had the highest scores on all dimensions except complexity; Brooklyn scored the highest on this dimension. These observational measures will be used to validate digital measures of the same urban design qualities. Once validated, these digital measures can be included in our ongoing analyses of human health data.
Funding is provided by Robert Wood Johnson Foundation Active Living Research, Award No. 58089, with principal investigator Andrew Rundle. This summary includes material presented by Marnie Purciel at a poster session at the annual Active Living Research conference held in February 2007 in San Diego, California. The field staff included Catherine Chong, Silvett Garcia, Jits Gysen, Victoria Lowerson, Joshua Margul, and Ellen Marrone.
