Here's a link to a story about Clearflow, software from Microsoft Research being used to model and avoid traffic jams.
The research is partially described in a Microsoft Research paper linked here.
In uncharacteristically logical fashion for Microsoft, Clearflow is a good example of taking an extremely complicated problem of traffic data analysis, and presenting it to a user as the solution to a straightforward problem: How should I get there from here?
The Clearflow system will be freely available as part of the company’s Live.com site (maps.live.com) for 72 cities in the United States. Microsoft says it will give drivers alternative route information that is more accurate and attuned to current traffic patterns on both freeways and side streets.
What's nice is it sounds like the interface will be exactly the same as using any old normal route planning software.
I'd like to know how much of it's traffic data is being pulled from some live source, rather than predicted through some model.