I think this is a repurposed former Railroad truss. Notice the pin-connections are at deck level rather than below. This is a very narrow bridge for a one-lane bridge. Piers appear to be of newer design than the bridge, which also suggests this bridge was moved in, after being retired at original site.
Photo taken by Gene McCluney in May 2007
BH Photo #128957
Judging by photo 4, I'm going to say that this was a relocated railroad bridge.