Google Navigation is now going to automatically select routes that avoid traffic, according to the Google Mobile Blog. The company says that real-time traffic conditions as well as historical traffic patterns are now factored into the routing:
You don’t have to do anything to be routed around traffic; just start Navigation like you normally would, either from the Navigation app or from within Google Maps. Before today, Navigation would choose whichever route was fastest, without taking current traffic conditions into account . . . Starting today, our routing algorithms will also apply our knowledge of current and historical traffic to select the fastest route from those alternates. That means that Navigation will automatically guide you along the best route given the current traffic conditions.
Google said the service is available in North America and Europe where both Navigation and real-time traffic data are available. Microsoft/Bing and Mapquest also feature real-time traffic data on maps. I’m uncertain whether this information also makes it into routing on their mobile apps.