How Mapping Software Gathers and Uses Traffic Information
When you use mapping software for directions, the app typically gives you two trip times: how long it would take to reach your destination driving the speed limit or a couple of miles per hour faster (a traffic-free utopia, of sorts) and the time it would take in current traffic. But wait a minute — how does a computer, which has never been stuck behind a jackknifed semi on the Beltway, know what traffic is like? The data source is rather simple: you, and others like you.
Read more via the Washington Post