I won't pretend I know exactly which parts of which roads, but I have read numerous times that the area is generally considered to be high risk, and I suppose it's no suprise. If you have roads going past one of the most famous monuments in the world, you're going to get drivers gawping at it!

I can imagine the Sanctuary, if rebuilt, might be worse as that road is dodgy anyway, and especially as that is the start of a national trail too with people parking up etc.
Although if they sorted that area out with speed limiting (I dunno, lots of signs/speed bumps/whatever it is works best) and made a 'proper' car park for the ridgeway start and the sanctuary itself (rather than the pot-holed nightmare it is currently), then perhaps things could be different.