Jaehyun Ha

Are perceived neighbourhood built environments associated with social capital? Evidence from the 2012 Seoul survey in South Korea

ABSTRACT This study examined the association between the perceived neighbourhood built environment and social capital in Seoul, South Korea, using the Seoul 2012 survey data collected by the Seoul city government. The survey polled 49,758 Seoul citizens from 20,000 households about their demographic and socioeconomic status, living environment, housing, and social environment. Multilevel regression models were used to analyze the relationships between the perceived neighbourhood built environment factors and three elements of social capital: trust, network, and participation. First, the analyses showed that statistically significant relationships existed between the perceived neighbourhood built environment and social capital. Second, social trust and social network showed significant positive relationships with most of the perceived neighbourhood built environment variables. This finding indicates that a walkable and safe community environment was a strong indicator of a high level of social trust and social network. In contrast, volunteer participation showed a different association with walkability and safety from crime. Finally, housing characteristics such as housing type showed statistically significant associations with the perceived built environmental variables. In particular, residents dwelling in high-density apartments showed a lower level of social trust and higher levels of social network and social participation than those in single-family housing.

Revisiting the Relationship between Urban Form and Excess Commuting in US Metropolitan Areas

This article revisits the relationship between urban form and excess commuting by analyzing 206 metropolitan statistical areas in the United States. Using the most recent Census Transportation Planning Products, we revalidated the importance of using multidimensional indices when examining excess commuting across metropolitan areas. We found that higher levels of polycentricity aggravate cross-commuting, while higher central city dominance improves excess commuting. In addition, our results indicate the significant impact of sprawl or jobs–housing dispersal on excess commuting. These findings shed light on the multidimensional relationship between urban form and excess commuting.

Spatial and Temporal Effects of Built Environment on Urban Air Temperature in Seoul City, Korea: An Application of Spatial Regression Models

In this study we examined the relationships between the built environment and urban air temperature in Seoul city, Korea. We developed multivariate regression models that address the relationship between built environment characteristics and the ambient air temperature with spatial statistics techniques. In addition, we analyzed the difference in daytime and nighttime air temperature to identify the built environment characteristics that affect the intensity of the nocturnal urban heat island effect (UHI). The large sample size of AWS locations in Seoul makes it possible to analyze the factors that influence ambient air temperature and UHI effect. The analysis results indicate that the sky view factor (SVF) and gross floor area significantly influence the daytime air temperature, while the building coverage and albedo showed strong relationships with the nocturnal air temperature. This study also demonstrated the importance of advanced spatial statistics techniques that control spatial autocorrelation and spatial heteroscedasticity in urban air temperature research. Our models confirmed the need to capture the effects of spatial autocorrelations within our spatial data. The findings of this study are valuable for understanding the complicated associations between the built environment and urban air temperature and to develop public policies to mitigate UHI effects.