Roadtrip

This was made in August of '09, when I went on a camping trip with some friends of mine.  I love road trips. We drove "Up North" as we Michiganders like to call it, to a camp site. We got to kayaking, tubing, and made food over a fire. It was a fun time. But the whole way there and back in the car, I remember seeing all these signs and thinking I wonder who came up with all of them. Who is in charge of designing the signs that dictate the behavior of traffic?