I looked it up, the fed highway administration states 14' as a safe minimum vertical clearance
which begs the question...if you're going to go through all the time and money to redo it...why only raise it 8"
Safety Eligibility
safety.fhwa.dot.gov
Some FAQ's posted with the video:
★★★ FREQUENTLY ASKED QUESTIONS ABOUT THE VIDEO / FACT UPDATES ★★★
1) North Carolina Law requires a height clearance of 13'6" - However, this bridge was built in 1940 and is NOT in violation because it was built prior to the current height standard. At the time of Its construction, it met all applicable criteria. The current standard cannot be applied retroactively, and re-building the bridge would be too costly. Lowering the road is also not an option due to a sewer line under it.
2) Why not just lower the road - The reason the road cannot be lowered is because there are sewer lines and water pipes below the roads surface, and the council could not lower the roads surface any further. Also if they wanted move the pipes, it would cost millions of dollars and will cause important utilities to be shut down for weeks or even months. So it’s not practical.
3) Why not lower the bridge, to make it obvious a truck won't fit through - For the same reason they have never raised the bridge, because the railroad company does not have to, they are legally within their rights not to raise or lower the bridge. Also a lot of traffic uses that bridge, it would cause more problems re-routing all that traffic that can still
JUST fit under it.
4) Why not just close the road, so no one can go through - Well maybe because most small trucks, buses & RV’s still do fit under the bridge, that the council did not want to interfere with re-routing all that traffic, just because 1 truck a month does not pay attention to warning signs, and crashes into the guard rail.
5) Why not just ban trucks past a certain height from using that bridge - Ok seems like a good idea, how will you inform all the random trucks using that bridge of that ban, will you use a sign stating the ban? I assume you will put that sign near the bridge somewhere, maybe right next to the BIG FLASHING SIGN saying "OVERHEIGHT MUST TURN" because obviously the truck drivers are reading all the signs at the bridge, right?
6) What happens to all the metal parts that break off the trucks - Jürgen Henn, the owner of the youtube channel Yovo68, picks up pieces of metal from Truck Accidents and sells them on his website, along with T-Shirts, now this man is an entrepreneur.
7) Waste of time and money raising the bridge only 8 inches - The main purpose of raising of the bridge another 8 inches, was to level out the 8-inch grade difference between the level crossing down the road and the bridge itself. The increased road clearance was only a side-effect of the project, its primary purpose was to level the grade of the tracks so the trains did not have to slow down and can run more efficiently.
Also found here:
Frequently Asked Questions about the 11foot8 canopener bridge in Durham, North Carolina.
11foot8.com