In this chapter a new road network decomposition approach is proposed. Necessary statements are proved in the first section, and the formal description of the approach as well as a brief review on relevant references are presented. The offered approach is completely based on the very features of the equilibrium traffic assignment and, consequently, forms the methodological basis for direct solving algorithms. The implementation of the developed approach to a single-commodity network can be found in the second section. A new decomposition technique for route-flow assignment in a general topology network is presented in the third section. The fourth section is reserved for a decomposition technique for link-flow assignment in a general topology network. Moreover, capabilities for route-flows aggregation and link-flows disaggregation which appeared by virtue of the new approach are discussed.