I have found googles traffic info to be pretty much useless.
I've had the complete opposite experience often here in California...
On Friday, right before the big holiday weekend, I was on-site with a client in downtown LA. A colleague of mine mentioned she needed to drive ~2hrs away through rush hour traffic to get home. Just for shits and giggles I fired up Google Navigation and as she was walking out the door, I told her which freeway to take and that she would be there in 1 hour and 20 minutes. She laughed at me and said she had never once gotten home that quickly leaving so late on a Friday. Sure enough 1 hour 20 minutes later I got her dumbfounded call saying that the estimate was right on the nose!
Again today, Tuesday right before rush hour I had to make a run from Beverly Hills to Manhattan Beach. Again, Google Navigation routed me against traffic on the 405 out of LA, missing the rush exodus probably by minutes, and on the return trip down La Cienega saving me at least 30 minutes on the 405 (I saw the gridlock forming on the other side of the freeway on my way down). Very accurate advice.
There is clearly some adaptive logic working on Google's side which allows Navigation to plan your route to bypass major problems. While it's not 100% accurate, I'm able to see a clear advantage to using it on long trips through the Los Angeles/Orange County area. :thumbsup: