An Electronic Frontier Foundation audit of automatic license plate recognition systems released in late November revealed that police in Grosse Ile have scanned 8.41 million license plates in 2016 and 2017. The location data picked up by the readers was then shared with additional databases on request. Of those scans, 99.92 percent belonged to drivers not suspected of any crime.
In Grosse Ile, a stationary plate reader sits on each of the two roads leading on and off the island. The readers read 97 percent of all plates passing them, according to police chief Joseph Porcarelli. License plate data is stored for 72 hours, after which it is purged, according to township supervisor Brian Loftus.
The system read 8,410,004 plates during the audited time period. Of those, 6,509 plates matched vehicles associated with a criminal or civil violation.