The other day I was looking around and found what was described as an older Interstate sign. But it looked nothing like I had ever seen before.
After asking a few people on misc.transport.road, I figured out it was an old prototype sign from the 1950's. When the Interstates were first being constructed, a contest was held amongst the states to design a shield for the fledgling highway system. In all there were something like 100 entries. The winning design was a combination of Texas and Missouri.
Well, the shield was designed by Texas, so Missouri must have had the “right” color scheme. There are actually a couple websites with pictures of some of the other rejected designs.
This comes from Idaho... I'm guessing that's a eagle?
The state isn't identified on this one, but a couple people have commented it looks like a Civil Defense sign.
This just in: H.I. Goldman reports on Roadgeek that it is an modified Civil Defense Logo 'The three-point triangle also represented a connection with Canada and Mexico "in a mutual bond of friendship and defense."' This shield was designed by Minnesota.
This seems simple enough, but it reminds me of the old Illinois Tollway logo.