These are awesome because you can take your sleeping baby out of the car, carry them with you without waking them up, and put them back in the car without waking them up. Shopping is 10x faster this way than when you have to spend most of your time comforting/distracting an awake and fussy baby.
Can we apply some if this science for making car seats for taller people. I am so unhappy when seat ends midway of my thigh or shoulders ram into headrest (mostly airplane problem).
https://us.britax.com/car-seats/marathon-70/ (see specifications)
Those detachable seats you see mom's carrying in the supermarket weigh about 10 pounds, and the base will be about the same.
We have this one, which is what I'd consider the gold standard. It's ISOFIX, and only rearward-facing since kids under 4 should not be facing front, and it's won basically every test there is:
http://www.besafe.com/product-int/izi-kid-x2-i-size/
It weighs 40.6 lbs. Quite a bit of structural steel in there, including a full integral roll bar and a brace against being rear-ended, both of which your linked Britax seat lacks.
Also bloody expensive, but if there's one thing I won't skimp on, it's the safety of my children.
https://us.britax.com/car-seats/marathon/https://us.britax.c...
So maybe in Europe you are going to have a harder time with self driving cars because you need heavier car seats, but you'll probably find a workable compromise. Yu can just build your base into the center seat or something.
Would Ubering with something like this work?
Even the ones for babies, that people for some reason I can't fathom like to carry around in the supermarket, are actually also 20+ lbs, you've just left 15 lbs remaining in the car occupying a seat while you're shopping. And they're also bulky.
2. could happen for children aged 4+ in a minivan-sized car. I've already seen it on some long distance buses. For younger kids however, they really need to sit facing rearward, but also must be well protect against side impacts, so it's very tricky to make something retractable that doesn't take a huge amount of space.