Your car has gone the wrong way down an express lane some distance, and deactivated when a semi trailer traveling 75mph in the opposite direction is detected. There is no shoulder, and it's stopping distance plus yours is greater than the remaining distance between you (.1 mile is way insufficient)

”Wrong way down an express lane” is super contrived. Those are the kinds of clear cut issues that self driving is guaranteed to be better at than humans.

If semi can stop in 6 seconds sounding horn would do it.

Every crash is avoidable by definition.

Human error/poor decisions, mechanical/electronic failures, acts of god could all reasonably be labelled as reasons.

Regardless of time.

Not every crash is physically avoidable _given a time constraint_. When you're a millisecond from impact, there's nothing you can do. One second, there exist many cases where there's nothing you can do.

10 seconds before impending collision, and it's hard to imagine the case where there's no time to react in some way that avoids the accident.