Authorities chasing the suspect in a fatal shooting at Delta State University in Mississippi used an automatic license plate reader to track the man as he traveled across state lines. The technology was also used in Virginia weeks ago when a disgruntled former television reporter fatally shot two former colleagues during a live interview.
Automatic license plate recognition systems have become increasingly popular with law enforcement in recent years. The devices allow officers on patrol to scan the plates of passing vehicles to determine if the cars have been linked to crimes, if drivers have outstanding fines and more. However, concerns over privacy and data storage policies have prompted lawsuits and a flurry of proposed legislation as the systems become more popular.
Here are five things to know about the readers:
HOW DO AUTOMATIC LICENSE PLATE READERS WORK?
Automatic plate recognition systems are usually composed of cameras, a processing unit and software. As officers drive on patrol, the cameras take photos of nearby vehicles, and license plate information is passed through databases to instantly check whether the car or driver has been linked to crime. In some cases, the cameras may also be mounted on fixed objects like bridges and toll booths. Driver data gathered by the systems may be funneled into larger databases and shared among law enforcement agencies using similar or competing programs.
ARE AUTOMATIC PLATE READERS ALLOWED IN EVERY STATE?
Approval of automatic license plate reading systems varies from state to state. Proposed legislation on automatic license plate readers was introduced in at least 18 states in 2015, according to the National Conference of State Legislatures. The organization says laws governing use of the devices were passed in Minnesota, North Carolina and Arkansas this year.
Police have said Delta State shooter Shannon Lamb was returning to Mississippi from Arkansas late Monday when an automatic reader scanned his plate as he crossed a bridge over the Mississippi River.
Despite many law enforcement leaders saying the devices have been a major help, some lawmakers aren't sold on the systems.
Republican Louisiana Gov. Bobby Jindal in June vetoed a bill that would have allowed law enforcement agencies to use automatic license plate readers as part of a pilot program, citing a "fundamental risk" to privacy. Jindal also said he was concerned that the data could be stolen or misused.
HOW LONG IS DATA STORED?
Data storage guidelines vary by agency, and some state legislatures are working to develop uniform storage guidelines.
A bill passed this year by Minnesota lawmakers requires data collected by automatic license plate readers to be destroyed no later than 60 days after collection if it isn't part of an active criminal investigation.
In May, Democratic Virginia Gov. Terry McAuliffe vetoed legislation that would have limited how long law enforcement may store non-criminal driver data. McAuliffe said a proposal to limit storage to seven days was a public safety risk. The Virginia Legislature rejected a suggestion for 60-day storage.
IS USE OF LICENSE PLATE READERS LIMITED TO LAW ENFORCEMENT?
Although automatic license plate readers are becoming more popular among law enforcement agencies, the devices are used in other industries as well.
Fort Worth, Texas-based Digital Recognition Network Inc. makes automated license plate recognition systems for entities like insurance and repossession companies. Last year, the company sued Utah's government over a law banning private companies from using license plate scanners. Company officials said the technology was primarily used to find stolen or repossessed cars.
WHAT ARE THE PRIVACY CONCERNS?
Organizations including the American Civil Liberties Union and the Electronic Frontier Foundation have argued the systems could allow local, state and federal officials to track the habits and whereabouts of innocent people. The groups have said the data collection is a violation of privacy and could be used to manipulate or exploit people if driver data falls into the wrong hands. The ACLU is suing a Virginia police department over its data storage guidelines and has called for several policies to be adopted limiting use of the systems to law enforcement, limiting data storage on innocent people, calling for public disclosure when using the systems and more.