By simply passing vehicles on a highway, a city street or in a parking lot, car-mounted cameras can record up to 3,500 license plates a minute. A computer then saves and tags the plate picture with the date, time and location it was taken.
So who's out there scanning plates? And where does the information go? The answer is private companies, car repossession agents and more than 37 percent of large law enforcement agencies across the country.
Some police departments keep their own databases, but other law enforcement agencies and repo firms send it to private companies, like MVTRAC. The company is a leading plate recognition system seller, and it maintains a massive national license plate photo database.
"There's no law that would impact how the different municipalities and states would implement this, and therefore the potential for misuse or unintended use is extraordinarily high," said attorney Mary Ellen Callahan, a former chief privacy officer for the Department of Homeland Security.
This International Association of Police Chiefs survey shows some agencies keep the plate information indefinitely, while others delete data after a few months.
The association says it's critical to crime fighting and police keep the information secure.
"We don't know of a single instance where automated license plate recognition data has been misused or abused," said David Roberts, a member of the association.
MVTRAC says it keeps its plate data indefinitely and only police and car repossession companies who've passed an in-depth background check can access its database.
"There's no real concern for privacy unless you've done something wrong. If you've done something wrong, if you're a murderer, if you are a child abductor, if you've committed a crime or if you haven't made your car payments in a long time, then that's a permissible purpose as well," MVTRAC employee Scott Jackson said.
MVTRAC says it does not sell the plate data to members of the public or marketing firms.