Lately, I started to take notice that Google Maps' traffic data is more accurate than the Garmin GPS (FM-based) traffic map and for that matter, Google seems to know traffic data even down to the local/surface street level. I've always wondered how Google gets it so right... I had a hunch it was user-generated data but this article explains it all. It is in fact, information collected anonymously via Google Maps for Mobile users who opted in to turn on the My Location feature. Learn more here.
All I've got to say is if anyone still doubts Google/Android mobile is the future, think again.