I suppose it's only a matter of time before we're constantly tracked, and the government knows where we are at all times, but it all sounds a bit scary to me:

In what would be the largest project of its kind, the Missouri Department of Transportation is finalizing a contract to monitor thousands of cell phones, using their movements to map real-time traffic conditions statewide on all 5,500 miles of major roads.

The article mentions that in addition to the (supposedly anonymous) monitoring of traffic conditions, cell phone data could theoretically be used to monitor speeding--I don't know how it works exactly, but you can imagine computer screens of call phone data being analyzed to see which ones were going 80 in a 60 MPH zone ... and then getting a traffic ticket in the mail.

I understand that in Britain they monitor traffic conditions much more closely with cameras than we do here in the US, and it's common practice to get a traffic ticket in the mail.

It's getting harder and harder to live without being constantly in the view of some sort of technology.

Mo. May Track Cell Phones for Traffic Data - Yahoo! News

Link from textually.org