When art and signage collide...

 (Photo from Eavacuteer.org)

So I was pretty hesitant to check out the latest New Orleans public art project when I heard that it was made of stick figures. How good could they be?
But I've got to admit that Douglas Kornfeld's 17 sculptures of universal symbol-type figures hailing a passing vehicle are pretty engaging. Easy to understand and big enough to see.
They're going to be placed at designated spots around town to help people get transportation out of danger should another hurricane slam into that beleagured city.
This brings up the whole question of double duty art.
Although a lot of public sculpture is informally used as meeting spots for people, giving directions, etc., pieces specifically designed for signage give rise to the question- "Is it good art, or good signage?"
Can this work be both at once?
I'm looking for more examples and welcome remarks and links...
 http://www.boston.com/news/local/massachusetts/articles/2012/03/07/sculptor_chosen_for_orleans_evacuation_art/