Google Maps has today rolled out a new feature: Live Traffic Conditions.
The data is available by clicking the new "Traffic" toggle button to the left of "Map - Satellite - Hybrid":
..When you select this option traffic signals appear for cities which have live traffic available. Click the icons and a zoom option appears:
Color coded routes indicate traffic levels for that city.. Give it a try! :)
This feature is also available on Google Maps for Mobile!