Despite these simplifying assumptions, the concept of equilibrium is meaningful for
several reasons. First, it is believed to be a reasonable approximation of traveler choice, and
leads to efficient solution methods and transferable conclusions, qualities that alternative simpler
behavioral assumptions do not share. Second, the modeling time horizon is often long enough to
assume that most travelers have discovered the shortest routes for their trips. Third, advances in
advanced traveler information systems (ATIS) and other ITS technologies can make travelers
much more aware of network conditions than was typical in the past. Finally, adoption of the
equilibrium principle makes available methods from economics for evaluating the potential
benefits (or disadvantages or costs) that accrue to travelers following a change in travel
conditions due to implementation of certain transportation projects or policies. Thus, when
comparative analysis is required, these features have made equilibrium-based traffic modeling
the predominant approach used in practice to date.