Abstract
The development of an internet-based travel information service for motorways and inter-urban routes in the south of France (MISTRAL) is described. This uses realtime data supplied every 6 minutes, incident data and journey time data. Map-based displays are used with colour codes to depict the traffic flow situation. The traffic flow is determined from counting stations and from incident information. The exact zones of any road closure are depicted. Symbols are used to depict different types of events on the highways. In very serious situations such as extreme weather a message is printed across the top of the map. The information is also broadcast by radio and may be intercepted using RealPlayer technology.