This is the Yaxi Expressway in southwest China's Sichuan province. It features some of the highest and longest bridges in the world.
Here's a little article about it: https://themindcircle.com/yaxi-expressway-traversing-the-clouds/
Side note: am i the only one who finds this crazy scary to look at? I'm sure it's awesome driving on it, but looking at it from afar it looks wild.
Yeah, i'm not saying it's not safe, just the thought of a highway being that high up in the air feels...unnatural somehow.
I get why they do it though. You want to minimize elevation changes and avoid doing what roads through mountains usually do which is a lot of winding curves to climb up and down the mountain. That would massively slow down traffic and is way less safe.
My gut feeling says roads should be at ground level if possible but actually that would be bad in this case. If this were at a lower elevation you'd need a lot more tunnels to go through the mountains, and tunnels are vastly more expensive and time consuming to build than viaducts and bridges.
China also loves to elevate not just roads but also its train tracks on viaducts, even when they're not necessarily dealing with mountainous terrain. You sometimes see very highly elevated railway viaducts in flat, open farmland. And again this intuitively "feels" wrong, but the reasons for this are actually very logical:
Firstly you minimize environmental impacts when you just have to place support pillars instead of an entire road or train track on the ground. You can leave the space below free to be used more or less normally.
Secondly having a road or track elevated protects it from floods, and China has gotten so good at building these that it's faster and cheaper than an elevated earth embankment.
And lastly, it's a way to guarantee no animals or people wander onto the tracks and cause accidents.
A lot of these reasons also apply when it comes to highways too, so yeah, logically it makes sense. Structurally it's probably very well engineered and maintained. And yet despite knowing all that i just look at it and i get this weird feeling that cars just aren't supposed to be that high up in the air...