License plate readers come under fire from ACLU

Earlier this week, the American Civil Liberties Union (ACLU) released a report detailing the use of automatic license plate readers by law enforcement agencies around the country. At issue in the report dubbed, “You Are Being Tracked,” is the wide variation and, in some cases, lack of rules surrounding how information gathered from these readers is used and stored by law enforcement. The ACLU says this raises serious questions about the protection of drivers’ privacy rights.

For example, the report, which is based on documents obtained from nearly 300 police departments, found that that under the policy currently in place at the Pittsburg Police Department in California, license plate readers may be used for “any routine patrol operation or criminal investigation.” While most law enforcement agencies do prohibit the personal use of license plate readers, the report said these may be the only restrictions in many cases. In fact, a document obtained by the ACLU from the Scarsdale Police Department in New York, said that use of these readers “is only limited by the officer’s imagination.”

In addition to a lack of detailed polices governing the use of license plate readers, another bone of contention from the ACLU was how long these police departments kept the data it gathered from readers. According to the report, retention of license plate data ranged from as little as 48 hours to indefinitely. The ACLU found that only a small fraction of license plate scans are flagged as “hits,” which are those license plates found to match a vehicle that may have been stolen or used in a crime. For example, of the 1,691,031 plates scanned by the Minnesota State Patrol between 2009 to 2011, just 852 citations were issued and 121 arrests were made.

"The spread of these scanners is creating what are, in effect, government location tracking systems recording the movements of many millions of innocent Americans in huge databases," said ACLU Staff Attorney Catherine Crump, the report's lead author. "We don't object to the use of these systems to flag cars that are stolen or belong to fugitives, but these documents show a dire need for rules to make sure that this technology isn't used for unbridled government surveillance."  

The ACLU has made several recommendations for government use of license plate scanner systems based upon this report. These include:

  • Only using license plate readers to investigate hits and other instances in which law enforcement authorities “reasonably believe” plate data may be relevant to an ongoing criminal investigation.
  • No storage of data on innocent people for any lengthy period of time. The ACLU says this should be measured in days or weeks, not months or years.
  • Giving people a way to find out if plate data of vehicles registered to them are contained in a database
  • Prohibit law enforcement agencies from sharing data with third parties that do not adhere to the same policies and also requiring them to be transparent about whom they do share this data with
  • Requiring any entity that uses license plate scanners to issue and annual report on their usage of the technology

Of course, this is not the first time that privacy concerns have been raised about the use of license plate scanners. In May, privacy rights groups filed a lawsuit against the Los Angeles Police Department and L.A. County Sheriff’s Department after they reportedly refused to turn over information they collected using the technology. Just last month, city council members in Iowa City, Iowa, voted to ban the use of license plate readers except for parking violations.

Despite the loud cry from privacy advocates about limiting the use of license plate scanners, there have also been some vocal proponents for their use.  NetChoice, a trade association representing eCommerce businesses, issued a statement on its website following the release of the ACLU report calling it “well intentioned, but off the mark.”

“The fact is, license plate readers are a technology that benefits us all by helping to find criminals and save lives,” said Steve DelBianco, executive director of NetChoice “This technology helped capture the men responsible for the failed Times Square bombing. It also allows us to monitor access to sensitive facilities and private communities, and to enforce payment in parking garages.  License plate readers keep insurance rates and interest rates lower, by helping to recover vehicles that are stolen or in default on leases and loans.”

DelBianco compared the objections to license plate scanners to those that were once voiced about Caller-ID and cellphone cameras. Additionally, DelBianco said that private companies using license plate readers have helped solve crimes, recover property and even save lives.

“Vendors who use the technology responsibly have robust data security and privacy practices, and tightly control who can access the information,” DelBianco added. “Our laws shouldn’t discourage innovation in new technologies that have many benefits.  Let’s focus on doing everything we can to stop bad conduct - no matter what technology is involved.”

Retired Police Officer Frank Borelli, editor-in-chief of, said that the use of automated enforcement technology aids police departments by enabling them to crack down on a variety of criminal infractions.  

“Not only do automated license plate readers (ALPR) passively seek and detect those with suspended, expired or revoked vehicle registrations, but through the use of connected databases and data mining, they can also use information attached to a vehicle’s registration to find those with open warrants, revoked/suspended licenses, etc.,” he said.  The ALPR has the potential to increase enforcement efficiency on the part of patrol officers.”

Borelli does believe that law enforcement agencies need to have sound polices in place about the use of plate readers, however, he says challenges will remain.

“Law enforcement agencies should control, through policy, what information is retained.  If a license plate is scanned, automatically checked, and no violation found, then the record of that contact should be erased. That way we’re not ‘tracking citizens’ via this automated system,” he added. “The challenge that presents is making a defense in court against an accusation of targeted or prejudicial enforcement.  If you can’t prove/show all those plates that were scanned and clear, then how do you prove you ever scanned anything other than those you took enforcement action against? Like everything else, anytime information is collected, there has to be proper policy in place and enforced to protect the rights and privacy of the citizens.”