In this work potential benefits and drawbacks of providing information to road users are discussed. To model the complex behaviour of road users multi-agent-techniques are used. A special agent-architecture is proposed and discussed. To consider the impact of pre-trip-information, coordination games, like the El-Farol problem and the minority game, are studied and interpreted in the context of route choice scenarios. Additionally, the impact of en-route information is studied by simulating a basic two-route scenario with dynamic and static agents. A correlation analysis yields that the traffic system is destabilised by en-route information. The overall performance of the system is reduced by the effect of concentration. Different types and ways of generating current information are tested. It is found that the nature of the information influences the potential benefits of the information system strongly. As potential application an Advanced Traveller Information System is introduced, which comprises an agent-based simulator, which is coupled to a stream of on-line data. The framework provides network-wide information about the current traffic state. It is applied to the freeway network of the felderal state of North-Rhine Westfalia (NRW). Results are presented and further applications are discussed. To provide predictive information different methods to forecast traffic are analysed and discussed. Heuristics generated by an statistical analysis of historical data are studied. The daily traffic demand is classified with regard to daily, seasonal characteristics, as well as special events or directional flow. To provide a prediction for arbitrary horizons heuristics are merged with a constant model. The model delivers good predictions for a short and long-term traffic forecast.