Tollbooth plazas aren't the only locations that scan car tags like the E-ZPass. One wary driver in New York City, known to the Web as Puking Monkey, recently modified his car tag to moo like a cow when activated.
"I drove around [Manhattan] and realized, Wow, this is being read everywhere!" says the man, an engineer who works in the healthcare industry. He asked Popular Science not to disclose his identity for fear of reprisal by his employer, plus the risk of being banned by E-ZPass.
E-ZPass is a device that drivers can buy in 15 states to zip through tollbooths across the country, usually without stopping. More than 24 million tags-and growing-exist in the U.S. alone. Each "listens" for a wireless signal broadcast by an electronic reader. When that signal is strong enough, a tag draws power from an onboard battery to broadcast its serial number back to the reader. The reader then relays the information to a computer server to bill the customer linked to the tag.