I took this picture with the intention to use it to replace the smoothness=very_horrible picture on the smoothness wiki. It’s very hard to find tracks with such horrible smoothness, and the one on the wiki and this one are about as bad as it gets without being completely impassable. I think the main disadvantage of the one currently used is that you can’t clearly see how deep the ruts are because they’re filled with water. I don’t think it’s surface=mud though because the surface is still firm enough to cause damage to a vehicle with insufficient clearance. The surface needs to be quite soft for these ruts to form anyway.
I think the picture proposed here shows clearly that the distance between the top and bottom of the rut (red lines) is more than 24 cm (green arrow). Maybe it should be cropped more to hide the fact that you could probably drive around it with a " heavy-duty off road vehicle" and get through. It requires good driving skills, which should not be a requirement if I conclude this correctly from this thread.