"requires human intervention every 13 miles" is a horrible metric, because it makes it sound it's not so bad until you remember that the moments for intervention are unpredictable and are also when you're just about to die.
It’s like supervising a teenager learning to drive, ready to take over at anytime.
It’s a lot less stressful to just drive myself.
As of now, I’d trust a teenager I’ve personally taught over some ML system any time.
I'm not saying that 13 per mile is good enough, but the metric does seem useful.