My gut instinct was that they're definitely not built in the '60's; they look fairly new to me.
I looked it up, and sure enough: Both the Roanoke River and US 158 bridges were built in 1999/2000, per NC's bridge inventory (see page 133).
I see. It says 1999. They must have been replaced then cause the highway opened in the 60s.
Compare it to the Dunn bridges and those haven't been replaced since then?
Yes, the Dunn bridges are original 1955 structures.
Here are some tips on figuring out this kind of question in NC...
- Original 1960s bridges on NC interstates have no shoulders at all and have the railing style like this (many covered by guard rail now) -
https://goo.gl/maps/kKDP1BiQw6cBb5CVACould a 1960s bridge be rehabbed instead of rebuilt entirely? The modern railing gives a hint but not the whole story...
Compare the underneath of the US 158 interchange which has modern piers -
https://goo.gl/maps/mJpo9VdwrV13gVUg9Compare the underneath at Exit 97 which has original piers, plus new piers added to get shoulders onto it -
https://goo.gl/maps/mSkGGd2BzzZzQ1Tv8On the first bridge I link way above, the surface has been rehabbed but nothing else.
The US 158 interchange used to be really dangerous northbound because the on-ramp from US 158 ended entirely before the adjacent railroad bridge and there was next to no merge area. This has always been a very busy interchange.
For bridge dates in general:
If you want to know when a bridge was built (or rebuilt - sometimes they have original and rebuilt dates) go here -
http://bridgereports.com/If you want to know when a bridge rebuilt entirely since 2011 was built prior to replacement, go here -
https://web.archive.org/web/20110501230146/http://www.uglybridges.com/