That looks to be a bridge over a drainage/irrigation ditch. It's likely, then, that it is a privately owned structure and not a public right of way. Therefore, the landowner, or some such private party is responsible for maintaining it. It may have been one of those cases where, "We'll get to fixing that bridge someday." Well, I guess it's now Someday!
John Deeres have their doors to the left side of the instrument console, at the front of the cab, so the operator should have been able to open the door and step carefully (As would anyone following his footsteps
) out of the cab to safety.