Where does Google get it's live traffic data from?

Referring to a post that I wrote earlier, Google’s - Live traffic Layer, ever wondered how Google collected this data? I was wondering the other day, how Google received live data to display it on their maps as a layer! I looked up the web and found something very interesting and am sharing the same with you all.

As we all know, the traffic layer is available most accurately in several states in USA. Most major metro areas in the US have sensors embedded in their highways. These sensors track real time traffic data. Easy to miss at high speeds (hopefully anyway, traffic permitting), more commonly noticed may be the similar sensors that often exist at many busy intersections that help the traffic lights most efficiently let the most amount of people through. The information from these tracking sensors is reported back to the Department of Transportation (DOT). The DOT uses this data to update some of the digital signs that report traffic conditions in many metro areas. They also openly share much of this frequently updated data out, which is how Google reportedly gets this data for the major highways in the metro areas it offers traffic reporting for.

Google has now also crowd sourced the collection of real time traffic data via mobile phones. The way in which they are doing this is pretty cool, and may prove to be a way to some day provide quality real time traffic data for all roadways. If you have a Google Maps installed on a mobile phone with GPS capabilities enabled, your location can be transmitted to Google in real time, allowing them to determine the fact that you are on a particular road and traveling at a certain pace. When Google combines your speed with the speed of other phones on the road, across thousands of phones moving around a city at any given time, they can get a pretty good picture of live traffic conditions. Google continuously combines this data and sends it back to you for free in the Google Maps traffic layers. In this way, Google can now offer traffic reports for secondary roadways, routes not necessarily containing DOT sensors.

We now have a list of all the places where Google shows live traffic information. Check out this awesome map from Google, here. You can read more and see the Google’s traffic layer in action here. If you have read so far, I am sure you would also like to know more about the Google Bicycle routes layer.