The Google overview shows shadows. A slab would not create that much of one. Street view angled over reveals bridges as twin steel deck girders.
I think it may be an error. At least in the last 30+ years there has never been a through truss bridge there.
I have been going over these bridges since the early 1990s, and I do not remember a truss bridge at this location.
I would agree these bridges are lost.
Looking at the google system I don't think this is a truss bridge at all. Looks more like a poorly maintained concrete slab bridge. This is the future of these slab bridges, they are not going to last a century like the truss bridges they are replacing. They will more then likely end up like this bridge, structurally deficient after only 45 years in service.