I think 50 years is being overly pessimistic. Self-driving in temperate climates is probably pretty close (<10 years). Waymo has pilot programs currently underway in California and Arizona[1][2].
The thing is, I see no way to have full self driving without AGI. And I don't think humanity is anywhere close to developing AGI. Without AGI you can have level 4++ self driving, maybe, but not level 5.
> The thing is, I see no way to have full self driving without AGI.
Why? AGI seems like a significantly harder problem than self driving cars (itself a hard problem admittedly).
What I personally think will happen is we'll meet somewhere in the middle: we can redesign roads/cars to make solving the problem of self driving easier.
I would say that I would feel comfortable falling asleep in a 5 while it is driving nontrivial distance and/or road conditions, but I would not feel comfortable doing so in a 4++.
[1]: https://techcrunch.com/2019/09/16/waymos-robotaxi-pilot-surp...
[2]: https://www.theverge.com/2019/10/10/20907901/waymo-driverles...