This work is the result of several years of research into the modelling and efficient solution of problems in transportation planning and related areas. It aims to provide a unified account of the development of models and methods for the problem of estimating equilibrium traffic flows in urban areas, as well as to show the scope and limitations of present traffic models. The development is described and analyzed by use of the powerful instruments of nonlinear optimization and mathematical programming within the field of operations research. The first part of the book is devoted to mathematical models for the analysis of transportation network equilibria. The second part deals with methods for traffic equilibrium problems. This title should be of interest to researchers in transportation, operations reserch and quantitative economics, who wish to extend their knowledge of equilibrium modelling and analysis, and of the foundations of efficient optimization methods adapted for the solution of large-scale models. This book is also suitable for advanced graduate courses in the aforementioned areas.