"These billboards use the latest technology in outdoor advertising to cycle through images every four to 10 seconds, displaying multiple messages from one or more advertisers on one sign."
"Two studies found that they are not traffic hazards, and the Federal Highway Administration (FHWA) has concluded they don't violate federal law. But not everyone favors them, and the studies themselves have been challenged. Opponents of the high-tech billboards say the signs are dangerous distractions, as well as "visual clutter" that detracts from the natural beauty of America's landscape."
"Digital billboards are still a rare and recent addition to the nation's roads. They account for about 700 of an estimated 450,000 billboards across the United States, according to the Outdoor Advertising Association of America (OAAA), an industry trade group. They're made of tiny LEDs - light emitting diodes - and can cost upwards of $250,000."
"So far, they are legal in 38 states and more states are grappling with whether to embrace them after a recent FHWA memo said the signs were not violating the law along interstate and federally financed roadways."