As of 2012: the truss is now just an ornament, repainted and resting on a concrete stringer bridge. The road was widened in 2002.
Hunterdon County NJ has truss bridges everywhere. Dozens of them, maybe as many as 100. Through trusses and ponies, we've got iron and steel bridges that were built just this year, and a wide selection dating all the way back to 1868, and a wooden covered bridge even older than that.
Once upon a time, back when New Jersey really was the "Garden State" and this was a sleepy rural county, all of our single lane bridges could do the job, many of them still spanning creeks and rivers on unpaved roads. But when the big highway went through in the 60s, and the county opened up to suburban and exurban development, these bridges soon became inadequate. And quite a few had to be replaced. Not to mention that, with all our streams, creeks, and rivers, we've got a lot of seasonal flooding going on, and many of the old bridges get swept away.
So the county set out to do bridge upgrading and replacement. And found that in order to get federal dollars to help, they had to meet federal width and strength specifications. And money is always tight anyway. So when these old truss bridges got widened, out came the trusses and in went the concrete.
And then the trusses went back on. Huh? Why? Sure, I'd like to say "Oh we have this great sense of history here, and are all proud of our past, and willing to spend whatever it takes to keep that old time rural feel alive", but that's probably nonsense. The truth is, it's probably much cheaper for the county to just give the old trusses a coat of paint and then screw them to the top of the concrete spans than it is for them to bring in a guy with a torch and cut them up for scrap and haul them away. And they DO make outstanding secondary crash barriers.
At some point in the 21st century the county-wide decision was made to make some extra effort to at least make these old bridges semi-functional if possible, but for a decade or so the approach was to just bolt them back on and walk away. This bridge is one of those now, but at least the truss is still around. It's just another single exhibit roadside museum, and the only folks who will notice that are those reading this web site.