I just saw this post today about how Sirius will be including traffic maps and data with their service. The more interesting thing is that XM is already sending this data in their XM NavTraffic system. They are sending traffic data in their signals that can be sent to a car navigation system and overlayed on the map. Also the navigation system can reroute the directions to avoid traffic congestion. The 2005 Acura RL has this system as standard equipment.
Now, I just wonder if Honda will offer this upgrade for our 2004 Odyssey. (Which I doubt) More likely, Alpine, which makes the Honda and Acura navigation systems will come out with an aftermarket product.