Perhaps you thought the traffic light would stay yellow a few seconds longer, but it suddenly blazed red. You felt lucky to get through the intersection unscathed -- until you received a traffic ticket in the mail. A hidden camera installed on the traffic light captured your infraction and your license plate.
Or you're in a rush, pulling up to a storefront and parking your car -- just for a minute -- in front of a fire hydrant. "No harm done," you think as you rush out with your package and pull away. That is, until you receive a mailed citation for the infraction. A device the size of a hockey puck was installed in front of the fire hydrant to alert officials of violations.
Thanks to an increasing number of surveillance cameras and detection devices recording driving habits (and violations), even when we think we're alone, we're not. But in some cases, these cameras have backfired. Chicago installed red-light cameras -- and then removed some of them at low-crash intersections. Los Angeles didn't have much luck getting citizens to voluntarily pay citations issued as the result of red-light cameras, so it removed them in 2011 [sources: Shannon, Byrne, Garrett].