Google has unveiled this Friday (Mar 30th) a new feature for Google Maps: real-time traffic info. Users will be able to simulate time travel by using real-time traffic info from the maps service. The real-time is still beta, and so Google Maps will also provide standard time travel info.
Time of travel estimation has been always present in Google Maps, but the information was based off historic and mathematical estimations (based on distance and route) rather than real-time real-life information. Travel estimation was based on average conditions instead of actual conditions for the time of travel.
The new feature is being built by using data from Android users who leave the "My location" turned on in their devices. The more Android users leaving their "My Location" turned on, the more accurate real-time traffic data Google will be able to provide.
The service is currently available only for U.S. users.