Is it me or do they? Every time I'm behind one they look like they don't track straight. It looks as though the rear tracks about an inch or so to the right. I know it could be an optical illusion or parallax thing going on. I've followed to where I'm more towards the center line but still can see the whole left side. Even the front and rear tire appear to follow different tracks ( I realized all the camber on the Twin I Beam might make it look that way ).
When the roads are wider, I've moved way over to the right and don't notice seeing the whole right side of them. It's not just one, it's all the Ford vans I see. I've seen cars before that have had collision damage and drive dog leg and the Ford vans appear to do the same. Try it the next time you're behind one. I haven't noticed this with GM or Dodge vans.