I accidentally found this tunnel in the UK, where the A51 was straightened in the 1960s, cutting the yard off from most of the adjacent land. The viewpoint is from the resulting 'loop' of the old road.
The 'new' road runs across the top, left to right (and vice versa).
It's only visible from a very small area and few people will have spotted it - I've gone past many times and only know it's there because, to settle a pointless debate, I googled how many branches of Subway were in the vicinity. That location seemed very unlikely, until I investigated.
https://www.google.co.uk/maps/@52.8698612,-2.0918099,3a,90y,77.04h,84.52t/data=!3m7!1e1!3m5!1soVY3Z_7mmFI3E3myGj6_tQ!2e0!5s20110701T000000!7i13312!8i6656
It would certainly be a struggle to operate there today by crossing the main road all the time.
There are farm tunnels under the R433, either side of Rathdowney, these days.