The surveillance camera on your street corner: lawful spying or constitutionally problematic?

The cameras that scan your car on your commute to work have quietly become one of the most widespread surveillance tools in America. 

They record vehicle sightings, feed searchable databases and, when agencies choose to share data, can connect searches across jurisdictional lines. 

Recent courts have upheld the particular ALPR networks before them, but they have left open whether a denser, more revealing system could cross the constitutional line.

What are ALPRs? 

Automated license plate readers (ALPRs)...