My headcanon is that during construction the measurements where taken wrong and instead of rebuilding the section to properly fit an offramp, people just continued by building a sharper turn.

I believe it. They redid a sweeping highway interchange overpass here, and several months after they finished, after numerous cars had crashed straight into the bridge wall at the beginning of the sweeping left turn, realized that the point where the bridge meets the ramp was misaligned due to a "miscalculation." This left the road with a flatter 'X' shape, and when you began the 60MPH turn and your front tires unloaded over the misaligned section, you lost traction and skid straight into the side of the bridge. They wound up 'redoing' it but you still have to slow way down when you go over that section.