You read the summary and not the case, didn't you?
bread truck parked on the highway,
The truck was therefore on the wrong side of the road.
It has been held that, where one unlawfully parks a truck upon a highway
Maybe you didn't mean to imply in your post that parking in a legitimate parking space on the wrong side of the road is negligence per se. If that was your intention, then I was wrong. But if you intended to imply that parking on the side of a street that isn't a highway in a legitimate parking space but facing the wrong direction is negligence per se then you have not shown that with this case.
EDIT - and right hand side is where all vehicles drive in America. If the law meant Driver's side, it should have specified that. Or are all Post Office delivery trucks in violation of the law?