in the manual it says roads are supposed to blink different colors when you have the traffic flow enabled but i havent seen any colors on my routes and i have it enabled and i live in the DC metro area so there should be some sort of traffic. all i use it for now are traffic updates on traffic events.

I live in the DC metro area and the traffic flow works ok for me. Zoom in on DC and look at I495 and I395. If you don't see the flashing lines then you may have a problem. So far I love my D2 and the Nav traffic works pretty well. Good luck.