"They do not conform to federal rules," said Doug Hecox, a spokesman for the Federal Highway Administration, a division of the U.S. Department of Transportation.
"The signs have a URL – they're encouraging drivers to go to a website," Hecox said.
The use of signs for advertising purposes has been prohibited since the 1960s. Hecox said the signs in question -- which currently dot roadways across New York -- specifically fail to comply with the Manual of Uniform Traffic Control Devices and the Highway Beautification Act.
When asked whether New York Gov. Andrew Cuomo knew in advance the signs violated federal law, Hecox replied, "Yes."