Elm Grove Police Department in Wisconsin developed an outdoor campaign to promote the concept, “Slower is Better.” Interactive billboards were placed by roads where speed had become an issue, feeding back to motorists the possible implications of their driving habits. The die-cut signs were placed over roadside radar trailers and were triggered by speeds above 25 mph.
http://thrivenowforyourfuture.com/ I love this. Look how they use nature as a canvas with the negative shapes in the subject matter. Very creative. You have to look at the billboards. I would of added a bit more direct response to it, but it is beautiful branding.