People from low socioeconomic status and ethnic minorities report the lowest rates of physical activity. This study will focus on African-American residents of public housing developments in 14 neighborhoods near Houston, Texas. Neighborhood characteristics will be assessed using scientific measures and residents will complete surveys and wear accelerometers to collect physical activity data. By associating this data, researchers will be able to determine what environmental characteristics are most important to encourage people to walk for both leisure and transportation. This better understanding of environmental factors most related to participation in walking will help inform intervention, policy and promotion efforts to increase physical activity.