The Henderson, Nevada, Police Department implemented automated license plate recognition (ALPR) in three patrol cars in May 2011 and the next month bragged that a stolen vehicle had been spotted and its driver arrested through use of the technology—which cost $160,000 to be installed in nine cars. Impressive technology, right? (Although it should be, with that pricetag!)

ALPR is maybe a little too impressive. ALPR systems can work night and day, and scan as many as hundreds of license plates per minute on both other moving vehicles and parked vehicles. APLR systems can be installed in cars, but also in places such as light poles and on bridges. So far, so good, especially when best and most used, even only used, to locate stolen vehicles and criminal suspects in their own vehicles.

But ALPR systems are used to collect and store information not only on people suspected of crimes, but on every single motorist, and are increasingly becoming a tool for mass routine location tracking and surveillance. APLR-generated information on all of us can be routinely collected and stored, even for years. Local and federal law enforcement agencies are rapidly building systems for pooling stored license plate location information across jurisdictions and regions. If current trends continue, we will eventually see the construction of a national database.

The deployment of ALPR systems is increasingly rapidly, and we could quickly reach a point where the devices are in operation on every block, and the data that they record will become equivalent to monitoring every vehicle with a GPS tracker. That level of tracking of individuals’ movements is a significant invasion of privacy that can reveal many facts about our lives, including what friends, doctors, protests, political events, or places of worship that we visit. This is alarming enough in the hands of law enforcement, but if such databases are subject to state and/or federal open records laws, other individuals, corporations, government agencies, or other organizations also could get access to when and where you are driving over sustained periods of time.

Although this fact has been increasingly ignored, forgotten or never learned since September 11, 2001, and the resulting USA PATRIOT Act (which is rife with civil liberties abuses), it is a core principle of U.S. democracy that the government does not invade people’s privacy by collecting information about citizens’ innocent activities just in case they do something wrong. More and more Big Brother surveillance by government must not become the “new normal” in American society.

Clear regulations must be put in place to keep authorities from tracking our movements on a massive scale. State and federal law should prohibit ALPR devices from storing data where there is not match to an offender list or other evidence of wrongdoing. Because police can use this tool for legitimate law enforcement purposes without storing data on the rest of us, adequate privacy protections will not interfere with legitimate law enforcement uses of this technology.