This appendix documents the technical steps undertaken to develop the feature Redefining Walkability: Examining Equity and Creating Safer Streets for All in DC. In the feature, we use open, crowdsourced, and public data to assemble indexes on equity, access to resources, environment, policing, infrastructure, and safety, all of which affect the walkability of neighborhoods in Washington, DC. Here we detail our background research, research approach, data sources, methods, validation processes, and limitations to our approach.