This paper reflects an interest in how policy and law are used to develop models for more just and equitable city planning. The paper draws on socio-legal scholarship and urban studies to consider knowledge formats for planning law decision makers (PLDM) in relation to social impacts for proposals for significant land use and development. Of interest is how planning law decision makers in the State of Victoria, Australia, know about social impacts and what role their own social capital plays in regard to this knowledge. The place for urban social tools such as social impact assessment, surveys, witness statements, plans and maps as a legal actors and knowledge instruments in the planning decision making process in Courts and Planning tribunals is considered.