An underpass is a passage or tunnel built beneath a road, railroad, or other obstruction allowing people or vehicles to pass underneath it instead of going over it. Full definition
There were four in the version I played, ranging from old favourites (such as Battle Course 1 from the SNES original) to brand new stages like one based on Urchin Underpass from Splatoon. (tiredoldhack.com)
He also adorned a wall on the Institut du Monde Arabe in Paris, motorway underpasses in Qatar, walls in New York, Melbourne, Jeddah and London. (widewalls.ch)
The master plan even calls for reconstructing a freeway underpass at Interstate 696. (automobilemag.com)