This study will develop, validate and apply a set of tools to evaluate the impacts of multiple policy and environmental interventions on increasing active school transportation and children's physical activity. It will also compare different interventions for their impacts (coverage and magnitude of change) and cost-effective ratios in different contexts. A specific focus will be placed on lower-income, inner city areas with high percentages of minority children. Policies being evaluated include multiple, school-environment related policies (e.g., school siting and attendance area designation) and neighborhood-environment related policies (e.g., sidewalk and trail development) at local and state levels. The study setting for model development and testing is elementary schools in the Austin Independent School District (AISD) in Texas, which covers the inner-city and urban area of the City of Austin. The findings and products will be shared with policy makers throughout the process and investigators will gather feedback to improve the user-friendliness of the tools.