Beyond a few studies, we have little understanding of how today’s children make use of their neighborhoods – back yards, front yards, sidewalks and streets, parks and playgrounds – for physical activity and even less understanding of how these activities vary with age. Yet these are the kinds of activities that are potentially affected by policies about neighborhood design. This study will develop and test measures of outdoor physical activity in neighborhood settings for children. In order to develop the measure, 50 families in the Sacramento area will be interviewed about children’s activity in the neighborhood, barriers to outdoor play, their attitudes about physical activity, and their reasons for deciding to live in their neighborhood. Half of the families interviewed will live on cul-de-sacs in order to examine if cul-de-sacs encourage more physical activity in children.