Already in 2004 there exists a really neat online service that not only gave traffic information but also the chance of getting into a traffic jam. (see screendump below).
I really liked this information since it gives you some indication on when it is best to drive in and around Paris. 10 years later the IDF website, still exist but I find it hard to find the same information for other regions in Europe. It would be so convenient to have this information for for Example the Benelux and Germany to plan ahead when going on a road-trip.
Am I not searching enough or does these visualizations of traffic information for other regions simply not exist?