I have been driving around Evansville for over 40 years and have noticed several decades of street signs. I believe the oldest can be found downtown near the river, Do you have any idea how old this one is?

It's probably not as old as the houses on First street but may be older than this one I found on Mulberry. This blue and white one is stuck on the side of a very old brick building. The sign's location behind a power line pipe makes it a little hard to see.

Here's one in my neighborhood. I have spotted about a half dozen of these mainly in the area of Evansville that was built in the 1950's. They are very hard to see but maybe that was the idea to have them blend in with the grass and trees around them. 

Here's the street sign that is the newest and the most visible. These are all across the US and in many foreign countries. It must be that combination of green and white that makes it easier to read.

If you have a different style in your neighborhood just leave a comment below and I'll try to take a picture of it and post it for everyone to see.