[googleblog.blogspot.com...]

you can now see up-to-date traffic conditions to help you plan your schedule and route. If you're in San Francisco, New York , Chicago, Dallas, or any of the other cities we now include, just click on the traffic button to show current traffic speeds directly on the map. If your route shows red, you're looking at a stop-and-go commute; yellow, you could be a little late for dinner; green, you've got smooth sailing.