Advances in Dynamic Traffic Assignment
Transport Economics, Management and Policy series
Edited by Chris M.J. Tampere, Francesco Viti and Lambertus H. (Ben) Immers
1. Dynamic Traffic Assignment: Recent Advances and New Theories Towards Real Time Applications and Realistic Travel Behaviour (Editorial) Francesco Viti and Chris M.J.Tampere 1.1 BACKGROUND Dynamic Traffic Assignment (DTA) is a set of criteria through which the demand for mobility is distributed over time and space on a transport network. Underneath this synthetic definition, there is a wide range of models and theories, which have been developed with the aim of solving this important transportation problem. Accordingly, this problem has been interpreted and solved in many ways, among which the most popular is the fixed-point approach derived from the two equilibrium principles of Wardrop (1952). These principles translate, in the transport context, the economic and game-theoretical principles of cooperative and non-cooperative equilibria in games (Nash, 1951). Traditionally, traffic assignment has been developed exclusively in the static context, before the seminal works of Merchant and Nemhauser (l978a, 1978b). This approach is still widely accepted in planning and design problems, or in general when congestion dynamics are of minor importance. The need for models able to capture in a more realistic way the dynamic features of traffic has been acknowledged since the growing application of dynamic management strategies, real-time traffic control and information systems etc., and also because of the increasing congestion levels worldwide. The simplifying assumptions characterizing static assignment approaches (e.g., steady-state conditions, time independency of the demand and the travel costs) are under these conditions unacceptable as they would fail in capturing important dynamic aspects and in assessing the impact...