Well, and 7 to 8 feet is pretty standard parking garage clearances. Maybe not quite enough to fit that lifted truck, but high enough for most (if not all) regular cars.
While most parking garages are that low, bridges usually aren’t, not unless they are going over a waterway or pedestrian path. And even then, usually they are at least around 10’.
Of course, yes. And in the US, it would certainly be signed out the ying-yang as drivers would have repeatedly hit it. A bit like this 8-foot clearance underpass in Renton, WA.
The previous Renton bridge on the site: 6-6.
Back to the culverts. I noticed that in Victoria, BC there was a railroad that passed under a
round culvert. Now it's a trail. Sometimes in the 70s, Seattle Times cartoonist Alan Pratt drew a proposed solution to traffic problems. The first panel was an exaggerated spaghetti interchange, and panel two was the same interchange, but built with culverts. The logic was that since culverts are so common, they must be cheaper, and if only the state could build highways with all culverts, they would be affordable. With the Seattle Times archive available online, I've been trying to find this cartoon, with no luck.
Also, the Snoqualmie Pass
Wildlife Crossing was built as a culvert, then filled in.