[raisedbyninjas]

We're talking about exceptional circumstances. With hundreds of millions of autonomous vehicles on the road, 1 in a billion is next Tuesday. We can minimize the need for this decision, but leaving the behavior undefined will just lead to headaches when it does happen.

[bryanlarsen]

We have currently ~30,000 fatalities in a year. What portion of these are trolley problems? Less than 1 in a million, I'd bet. What percentage of those trolley problems are entirely avoidable through proper defensive driving techniques?