while compact cities can foster traffic congestion and higher levels of air pollution compact urban development can limit travel distances reduce car dependence and facilitate the development of public transport systems there are also other nontransport benefits such as the preservation of countryside and reduced material and energy use oecd chen jia and lau increased urban density is associated with reduced transportation c emissions per capita and successful compact cities develop effective internal and external transportation linkages mixed land use and highquality urban services oecd