The initial objective of traffic forecasting was to provide information support for motorway operations, in planning road maintenance work, in decision-making for implementing operations measures, for toll station shift organization, and other needs. However, with the increasing emphasis on customer service, there is the clear need to enable the public at large to benefit from traffic forecasts so that each driver can best prepare his or her travel plans. Therefore, in addition to the usual information diffusion means traditionally used to inform its customers about traffic conditions (the radio station, the telephone information center, and the variable message signs), ASF now provides a new traffic forecasting service based on the two-fold principle of "dynamic" and "personalized" information. This new service, which has been on line since summer 2001 on the ASF Web site (www.asf.fr), provides ongoing and evolving information which specifically responds to the users requests. Thanks to historical data gathered on the whole network and processed with powerful and "state-of-the art" statistical techniques, customers have now on-line personalized traffic forecasts allowing them to choose the right time to plan their trip on the motorway.