Today’s law enforcement use License Plate Readers (LPRs) to detect stolen vehicles. These LPRs automatically scan up to 60 license plates per second. These scanners use OCR technology to match what they find with “hot plates,” plates for cars that have been reported stolen or linked to subjects wanted or under investigation. The technology is so efficient that aside from being affixed to physical structures, they are often mounted onto squad cars.
While this isn’t all that surprising, what you might find interesting is the fact that these records are kept between 48 hours and “indefinitely,” regardless of whether the logged information is linked to any cases under investigation. Below is a chart made by the ACLU, depicting the difference in retention periods between a variety of cities in the U.S.
So what happens if you want to get a hold of records linked to your license plate? Some departments will deny you access to that information, while others may only require proof of registration. Cyrus Farivar posted a piece on Ars Technica, The Cops are Tracking My Car- and Yours, explaining how he acquired his info and what he found.