I've just finished adding the MAX light rail Yellow Line in Portland.

I've decided that streets being mis-positioned are not the biggest problem with Tiger data. Rather, layers and intersections are. Now that I have read the Tiger documentation, I see that it does clearly state that there is no discrimination among overlapping layers (overpasses, underpasses) and that intersection points are put where the various paths cross. It is what it is.

Portland has several freeway interchanges with bridges, multiple layers of overpasses, train tracks, light rail tracks, and surface streets below. Unraveling the layers can be daunting. I started out being cautious, trying to preserve as many of the original nodes and ways as I could. Now I'm finding that it is quicker to go in and delete all of the intersecting nodes and ways in the middle and just lay down new ones as needed.

Of course, I still don't have anything to complain about. It does still mean that 99% of the mapping is already done, compared to the countries where folks are starting from zero.