1. Objectives of traffic modelling and congestion principle

1.1 Traffic modeling objectives

Like other fields of application, traffic models are simplified representations of a complex reality. They are therefore designed to meet a specific operational objective, and must be judged against this application. In particular, traffic modeling is generally used for transport system evaluation purposes. As explained above, evaluation has become an indispensable phase. It is often very difficult, if not impossible, to carry out direct measurements on the transport system: partial knowledge of system states, modification of existing systems, evaluation outside normal operation. Models can help to overcome these limitations by reproducing the overall behavior of the transport system.

The aim of traffic modeling is therefore...