Navigon have posted a comprehensive answer surrounding how traffic will work:
Regarding to all of your questions, here are some information on our Traffic Live services: Traffic Live blends seamlessly into MobileNavigator with easy to read displays and simple to use menus. The software automatically includes traffic information when calculating a route, and drivers receive immediate on-screen alerts to new incidents and congestion as they occur.
The NAVIGON MobileNavigator display also provides detailed information regarding the severity of the incident and the speed of traffic flow.
Our Provider INRIX uniquely aggregates and intelligently combines real-time traffic speed information from hundreds of thousands of GPS-enabled commercial vehicles, GPS-enabled consumer vehicles and mobile devices, and traditional road sensors in Europe.
Unlike with TMC or TMC Pro, the information is given in real time. We receive this information from various sources, such as NAVIGON Live users and various floating car partners (Floating Car Data). This enables us to find out further details in addition to the traffic reports, such as the current traffic flow speed on motorways and main roads, and to continually receive current, reliable and accurate information on the traffic conditions.
The real-time data comes from a combination of several valid sources. For example, we also work with various floating car partners. These partners also give us information on the current traffic flow speed. Combined with additional traffic data sources (sensors) providing traffic reports, this provides us with extremely reliable data that offer users real added value.
The service is actually available in following countries: Belgium, Germany, France, Finland, Norway, Netherlands, Austria and Sweden. Switzerland, UK, Spain, Italy will follow asap. It will not be necessary to install the service again, the countries will be supplemented automatically as soon as the service is available.
Regarding Traffic Service in France:
INRIX covers more than 300.000km of the French road network.
Coverage includes Autoroutes, Routes Nationales, a selection of Routes Départementales and Urbaines (most of them with inner city coverage).