This chapter provides a comprehensive overview of Ideal Traffic Assignment (ITA), a novel approach to transportation network analysis based on Ideal Flow Network (IFN). It begins by defining the foundational theory of IFN and its practical application, Ideal Traffic Assignment, outlining their assumptions, methods, and unique strengths. The axiomatic basis for the framework is established, followed by the derivation of the ideal traffic assignment model. The theoretical concepts are applied to a hypothetical urban network to investigate the systemic effects of network modifications. This demonstrates how the framework can be used to evaluate network structure and performance without relying on traditional origin-destination demand data.