All I remember about Superman IV right now is that Nuclear Man was terrible, and the ridiculous scene with Superman carrying the woman in outer space. I still don't know how she was alive during it. It was like the writers had stopped caring at that point!
Oh, it could have been even worse. Just check out the deleted scenes on the Superman IV blu-ray and you'll see stuff that is so awful you'll want to gouge your eyes out afterwards.
Well obviously it wasn't the most ideal place, but they didn't have a whole lot of time or options. And the tornado didn't appear to be actually passing over the overpass anyway
, so it was more them just getting out of the tornado's path.