here is what's called a pigtail bridge in the Custer State Park in the Badlands National Forest of South Dakota, right by Mt Rushmore

on the Iron Mountain scenic road, a 17-mile journey with 14 switchbacks, 314 hairpin curves, 3 pigtail bridges, and 3 narrow tunnels

the tunnels leading to Mount Rushmore were perfectly aligned so as you enter, Mount Rushmore is framed majestically at the far end. It teases visitors the entire way, building excitement for the participants. The Pigtail Bridges compliment the road by solving a problem and providing an exciting corkscrew route down the mountain.

https://traveltheparks.com/why-drive-iron-mountain-road-custer-state-park-to-keystone-sd/

https://myxoadventures.com/the-pigtail-bridges-of-iron-mountain-road/

https://www.hmdb.org/m.asp?m=89460