Cell phone navigation
Cell phone navigation

OK, this isn't exactly your car, but a device you carry into the car to use while you're driving.

When you use your cell phone for turn-by-turn navigation there's a whole lot of data streaming in and out of your car. And that data can be very useful for monitoring traffic flow.

Cell phone companies will send that data about vehicle speeds in various locations to companies that use it to provide real-time traffic information.

No identifying information about your car is shared, cell phone companies and traffic data providers say. Instead the data from many drivers is is grouped together anonymously and used to calculate overall traffic speeds on various roads. So while there may be the theoretical potential for individual tracking, it's not being used for that.

Data about your destination is also stored "anonymously," Verizon spokeswoman Debra Lewis said, not in any way that would allow someone to find out who asked for directions to a specific address.

Also, at least in the case of Verizon phones, it's all spelled out in a disclaimer you're supposed to read -- you did read all that, right? -- before you start using the app.

By Peter Valdes-Dapena @PeterDrives - Last updated January 18 2012: 2:12 PM ET
Join the Conversation
10 costliest cars at Pebble Beach

The $16.4 million Ferrari wasn't the only multi-million dollar car sold at this year's California classic car auctions.