It's open to traffic, providing the road isn't under water.
This bridge sits next SR 157. Is it still open or closed?
I cleaned your photo of the plaque up Tom, hope you don't mind. This is the best I was able to do. It's a little more legible.
Here are a few pictures of this bridge. Couldn't get any good shots due to high water and trees. The water was right to the bottom of the bridge, in fact the road to the north was completely under water. The photo of the plaque didn't turn out well, but you can barely make out the date.