General comment: I have not posted the responses above to be superior, to try to contradict anyone, to try to prove my worth, etc. in any way. I used to have many of the same mindsets that many of you have posted in this thread. One day I posted one of the summary charts for the 5 different levels and thought "man, this really is very vague / open to interpretation, etc.". Knowing that the SAE is made up of, duh, Engineers and being one by classical education, I knew this couldn't be the case. So a-searching I went. I was able to, as I posted above, download the whole J3106 paper and spend some quality time reading it. At first, I got lost in the endless loop of definitions. Definitions upon definitions upon definitions. Once I got through those, and read the text of the premise, it made much more sense. I would urge all of you, if you are truly interested, to download the paper and spend time reading it. It's not light reading. It's a technical paper. You need to read all the words and understand how they fit together. You can't skim it. As one of my old bosses said to me a long time ago "all of those notes aren't on the plan for the hell of it, read 'em". If you take some time to read through it, it makes sense. I hope what I posted in previous posts helps clarify.
For anyone who can't find it, the document is at this link: J3016: Taxonomy and Definitions for Terms Related to On-Road Motor Vehicle Automated Driving Systems - SAE International
I want to echo what Needsdecaf wrote. When I first tried to understand the SAE levels, they seemed really complicated. I had folks on this forum correcting me all the time. I think part of the problem is that there is lot of misinformation out there. There are articles written by "journalists" who try to make it is simple for "regular people" but actually get it wrong. I see articles all the time that get the levels very wrong. I am not saying I am an expert. But after reading the SAE document in detail and really putting it all together, I can say the SAE levels make a lot more sense to me now than they used it. Now, I feel like the SAE levels are very clear and really great ways to classify autonomous driving.
2027-2030, thereabouts, and with a wildly different sensor suite than we see in our current cars, and I still doubt it'll be truly "level 5" at that point. But by then I imagine we'll be able to sleep in the car while it drives us places in most conditions.
By the way, everyone on this list appears to be arguing / interpreting Level 5 not but the SAE definition of intent, but a different definition of actually being implemented.