This study evaluated the links between objectively measured levels of physical activity with objectively measured aspects of the physical environment around each participant's home, while controlling for sociodemographic covariates. Researchers used data from the Metropolitan Atlanta's Regional Transportation and Air Quality (SMARTRAQ) study of transportation, land use, air quality, and health in the 13-county metropolitan Atlanta region. They recruited 523 people from the study area, collecting data between 2001 and 2003 on individual's urban form, physical activity, and demographics. Researchers also asked participants to wear an accelerometer for two days during the study period to capture objective levels of physical activity. Final data was obtained from 357 adults. The results showed that measures of land-use mix, residential density, and intersection density were positively related with the amount of moderate physical activity per day. Thirty-seven percent of individuals in the highest walkability index quartile met the 30 minutes or more of recommended physical activity, compared to only 18 percent of individuals in the lowest walkability quartile. Individuals in the highest walkability quartile were 2.4 times more likely (CI=1.18-4.88) than those in the lowest walkability quartile to meet the recommended amounts of physical activity per day. The authors note that this study supports the hypothesis that community design is significantly associated with moderate levels of physical activity. They add that the results support the rationale for the development of policies that promote increased levels of land-use mix, street connectivity, and residential density as interventions that can have lasting public health benefits.