Ask HN: How would autonomous vehicles handle emergency services right of way?

happened to me this morning on the way to work. cars moved themselves into bus lanes and past the line on red lights etc. it's all very dynamic where everyone is looking at what everyone else is doing and we collectively iterate to a solution so the fire engine can get past and get on with its journey. my question is - this happens regularly on an annual basis but how would an autonomous vehicle handle the situation? what rules get to be ignored under this circumstance? surely we're not going to compile enough data to treat it statistically so the chances of it screwing up have to be orders of magnitude higher... I can see worst case scenario edge cases all the way down.