Whole US Crowdsourced by Google Maps: Shows Traffic Data from U

Google expanded its traffic layer to cover all U.S. highways and arterials when data is available. The maps show how fast traffic is moving.

Is done through “crowdsourcing,” using data from Google Map users and how fast they are traveling on roads.

When you choose to enable Google Maps with My Location, your phone sends anonymous bits of data back to Google describing how fast you’re moving. 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, then they can get a pretty good picture of live traffic conditions.

They continuously combine this data and send it back to you for free in the Google Maps traffic layers.