Some billboards on the highway are, in fact, watching drivers.
The Connecticut Better Business Bureau said its part of a new generation of data collection tools.
Over the past several decades, marketers have been collecting data from people through their use of computers and mobile devices.
Now, using cell phone signals, the BBB said marketers are tracking where people are going and at what time.
"Many people might be surprised to the extent we are being followed," said Howard Schwartz, BBB spokesperson. "When we use an app specific to a mall or store, marketers can follow us from store to store, up, down the aisles and see what you buy. The same with store discount cards. Data collectors know where we are what we are buying and more."
Schwartz said it should come as no surprise that billboards are being used.
He said the unsettling aspect is that most consumers don't even know they're being tracked.
Sellers and marketers said they are not looking for personally identifiable information.
The billboard system is called "Radar."
The BBB said an estimated 675,000 of them have been installed in countries around the world. That number is expected to grow.
Marketing information collected from consumers can also be sold to third parties without consumers' knowledge, according to the BBB.
Privacy advocates and some lawmakers have said that disclosure about the practices is lacking. They argue that consumers should be given the option to opt out of billboard tracking.
For information on how to protect digital identities, head to the BBB's website here.
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