14 DAY TRIAL // Google has added a new, potentially very useful, layer to Maps, allowing users to see the live traffic conditions in several cities across the US. Live traffic may not be something new for the highways but Google is introducing the feature for all arterial roads, making it much easier for commuters to plan their daily route by taking into account the traffic conditions.
“If the traffic looks bad on the highways, you'll probably want to know how it looks on the alternate routes through arterials. I usually would just guess that the traffic on back roads is light, but with this new launch the guesswork is eliminated: Google Maps will now show you live traffic conditions on arterial roads in selected cities,” Jordan Weitz, software engineer on the Google Traffic Team, said. “If you have Google Maps for Mobile, you can see the same traffic there and, better yet, help improve the data,” he added.
Zooming in on the city they're interested in allows users to enable the traffic layer. If the city is in an area where Google has traffic conditions data, a “Traffic” button will appear in the upper-right corner of the map. The roads will then be colored according to how congested they are with green meaning little to no traffic, yellow meaning medium congestion, red standing for slow traffic and red and black suggesting stop-and-go traffic. The colors are relative to the speed limit of the particular road. At a higher zoom level only the highways and the bigger roads get colored but moving in closer will color the arterial roads too.
The interesting part is how Google acquires this data as the system uses speed and location data from mobile phones with Google Maps installed to gather enough information to create a complete picture of the conditions across the city. The data is completely anonymized and Google went to great lengths so that even it doesn't have enough information to see someone's whole trips after they are completed. Still, sending the location data is optional and users can opt out at any point.