If you've been behind the wheel lately, odds are your trip has been tracked by small cameras called "automated license plate readers."
They're often mounted on law enforcement vehicles and street poles, and used by police to catch criminals. But in California, lawmakers are debating whether this technology needs restrictions to protect privacy.
The high-tech cameras zero in on the license plates of every car that passes, taking upwards of 2,000 images per minute.
The photos are instantly sent to national databases that log each vehicle's exact location, along with the date and time it was there.
More than 70 percent of the nation's police departments use this technology to find vehicles associated with crimes.
"If a vehicle comes into the area, it's instantly recognized," said Captain Ed Palmer with the University of Southern California Department of Public Safety.
There are 62 cameras that take photos of every car on the Los Angeles campus.
Last year, L.A. police chased and arrested a man in a reported stolen car after a camera on the USC campus took a picture of its plate.
"It's a force multiplier," Palmer said. "You can't be everywhere at once. So it enables us to get a look at almost every vehicle that comes through here."
But now, private companies have built their own databases, and are using these cameras, too -- cruising streets and parking lots and sharing billions of hits of data not just with law enforcement, but with anyone willing to pay, including private investigators, insurance companies, and lenders looking to repossess vehicles.
"They can track you around the country through these databases," said California State Senator Jerry Hill.
Hill wants to regulate the technology. He's pushing a new state law (S.B. 893) that would keep license plate cameras off private property, and ban public agencies from sharing their camera data.
"What we're trying to do with the legislation is create some safeguards so the public's rights and privacy are secure," Hill said.
The California Senate will vote on the new law next week.
In the meantime, license plate cameras and the data they collect remain unrestricted.