License Plates Tracked

Millions of digital records on the location and movement of Americans are being amassed using automated license plate scanners.
There are tens of thousands of the scanners scattered throughout the US.  Information in the databases can be reviewed weeks or years later.

http://www.nbc40.net/story/22863469/driving-somewhere-theres-a-govt-record-of-that

http://www.aclu.org/blog/technology-and-liberty-national-security/police-documents-license-plate-scanners-reveal-mass