[exDM69]

> Level 4 may work on a sunny day, but a small change in rain or road conditions could downgrade the system to Level 1.

This isn't the way it works. If a car says it can do "Level 4 on a sunny day" it means when you sit in the car and engage the autopilot (and it says it's safe to engage), then no human intervention will not be required during the course of the trip. If conditions change, the car will be parked without human assistance and wait for help (what happens next is outside of the scope). You could be sitting in the back seat, or your kids could be in the car alone on their way to school.

"Level 4 on a sunny day on some pre-certified highways" is ok. "Level 4 in San Francisco traffic" is also ok, and much harder. "Level 4 unless it starts raining and we'll deteriorate to Level 3" is Level 3, not 4.

This is the definition of autonomy levels from SAE, and they're pretty strictly defined.

[JumpCrisscross]

> This is the definition of autonomy levels from SAE

It's still domain dependent, right? If the rules say we're flattening precipitation and visibility within normal bounds, fine, but sometimes you have abnormal weather and badly-maintained roads. It is useful to compare hypothetical cars that autonomously navigate conditions no humans would dare.

EDIT: Never mind. The point of "Level 4" is it is competent in all reasonable operating domains.

[exDM69]

> It's still domain dependent, right? If the rules say we're flattening precipitation and visibility within normal bounds, fine, but sometimes you have abnormal weather and badly-maintained roads

No, it's not.

In Level 4, if there's "abnormal weather and badly-maintained roads", the car must be able to deal with the situation and enter a safe state. It can say "please sit down and wait for assistance" but it may not say, "take over the wheel".

In practice you'd probably disengage the autonomy and drive yourself, you take control and it does not give you control. If you can't sit on the back seat drinking beer or send the car to drive your kids to school (we're not considering legislation issues here), it's not Level 4.

This is an important distinction. "Level 3 in most conditions" is good enough to pass as "full autonomy" for most people, but Level 4 is a requirement for not absolving the humans on board for any legal responsibility.

[JumpCrisscross]

Got it. That's helpful. So Cruise/GM are 4G'ing a Level 3 vehicle?

[exDM69]

It's impossible to tell the level of autonomy from this article. What was shown in this article could qualify as Level 2, 3, 4 or 5.

To provide proof of Level 4 autonomy with video (in certain conditions), it would need to show adverse and exceptional conditions, such as terrible weather, accidents ahead, all routes to destination blocked or any other situation short of a force majeure disaster and then provide a safe contingency for that.

In San Francisco, that would probably mean finding a parking lot where it is safe to wait for assistance from your Transport Service Provide(tm). In rural northern Europe where I'm from, it would mean parking on the side of the road and calling your wife/mom/friend to pick you up :)