The purpose of this research is to help increase the capacity of public-sector transportation agencies (such as state Departments of Transportation, Metropolitan Planning Organizations, and transit providers) to preserve and enhance transportation-related quality of life (QOL) outcomes in their jurisdictions. QOL is a multi-dimensional concept that is closely related to the concepts of livability and social sustainability. Public-sector agencies are charged with promoting the well-being (i.e. QOL) of the public, and they often must work within a complex inter-organizational context, with overlapping and intersecting jurisdictions and responsibilities, in order to influence QOL. Because of their responsibility to promote QOL, many public-sector transportation agencies mention QOL, livability, and/or sustainability in their vision statements, mission statements, and strategic planning documents. Furthermore, U.S. Federal guidance and regulations that govern the practice of transportation planning, engineering, and performance management have begun to refer to issues related to livability and sustainability. However, these complex concepts are still ambiguous in meaning and application for many transportation practitioners. In order to effectively preserve and enhance transportation-related QOL outcomes, practitioners need a clear conceptual framework that links concepts of livability and sustainability to practical performance management tools for an inter-jurisdictional context. The primary objective and contributions of this research are the development of such a conceptual framework - the stacked systems framework (SSF) - and a methodology for applying it to enhance transportation performance management in an inter-jurisdictional context. In order to develop the SSF, this research begins with an extensive literature review that clarifies the relationships among sustainability, livability, and transportation-related QOL outcomes; and integrates the concepts of social sustainability, soft systems methodologies, and the field of transportation performance management. To apply the SSF, this research includes a case study of public-sector transportation performance management processes in metropolitan Atlanta. The case study analyzes the influence of the regional inter-organizational system of public-sector transportation agencies on transportation-related QOL outcomes; identifies gaps in the current set of transportation performance measures used for decision making at the regional scale; and demonstrates the value to decision making of incorporating recommended performance measures that can more appropriately link organizational actions to broader QOL and livability outcomes via changes in transportation service quality. The case study methodology can be extended for future development of transportation performance management practices in metro Atlanta, and reproduced for other regions and geographic scales.