This study analyzes factors that influence transportation efficiency in US metropolitan areas from 1980 to 2008. Transportation efficiency is measured using an index of population density, driving alone, public transit use, and walking/biking. The study finds higher transportation efficiency in areas with higher incomes, more college education, and state policies requiring urban growth management. However, the influence of government fragmentation, racial diversity, and segregation are more complex. Coordinated regional planning may improve transportation efficiency if tailored to local contexts.