Google on Tuesday added a traffic tracker tool to the Web and mobile versions of its Google Maps service. According to Google, it allows users to see how heavy traffic is in areas they're driving using a color-coded chart compiled from crowdsourced data.

How it works: Google Maps For Mobile users that have GPS on their phones enable Google Maps with the My Location feature, which, when turned on, sends anonymous pieces of data back to Google to show how fast traffic is moving based on the speed and location of the user's car.

"When we combine your speed with the speed of other phones on the road, across thousands of phones moving around a city at any given time, we can get a pretty good picture of live traffic conditions," wrote Dave Barth, product manager for Google Maps, in a blog post describing the new feature.

"It takes almost zero effort on your part -- just turn on Google Maps For Mobile before starting your car -- and the more people that participate, the better the resulting traffic reports get for everybody," he added.

As if to nip in the bud any suggestion that Google knowing where you are at all times is a little unnerving, Barth adds that "we only use anonymous speed and location information to calculate traffic conditions, and only do so when you have chosen to enable location services on your phone."