We need a radically new car seat design, either:
1. Super portable and quick to install/remove, or
2. Built into the car, safe for all ages, easily extended/retracted.
eg. "I need a 4wd vehicle for 2 adults and 2 bikes to take me to X park at 10am tomorrow."
The cost savings for car rental are predicated on increased utilization. Increased utilization is predicated on each car having more people using it on any given day. And these things don't scale infinitely -- each car can only serve a particular locality.
The number of variations that you propose is a fast geometric progression. Kids 0-12 months or so need different car seats from kids 12mo to about 3y need different car seats for older kids. The idea that you could support high utilization on "I want a car that has already installed a carseat for a 1-2year old + a carseat for a 5 year old plus a bike rack" is nuts.
(Regardless, also, parents carry a mountain of stuff that's THEIRS. The heck with a car seat, I need board books, toys, snacks, and wipes in the car.)
Only if you're an engineer. To a marketing person, you bundle groups of features together and price them at various tiers.
But I don't need or want to buy a wheel, batteries, cameras, lasers, etc. Those also should be upgraded as technology gets better but my box doesn't really need to be anything but a box.
So what if I could sit in my box and have a transporter thing come over and clip onto me and take me away? You could have child seats and I could have a lazyboy chair, or I might need 8 seats and you need storage space.
This would then let the actual transporters take other types of cargo too, rather than having a people vs items split. It would allow a pony-express style swapover rather than needing huge range in a single one. It would even allow completely different types of transport, what if my pod could just be clipped onto a big train and whip me to the other side of europe?
This would all likely have other downsides, but is a fun thing to think about.
TL;DR shipping containers
I really want to see a day, where I drive my car to work. It then drives other people around and picks me when I am finished.
You don't need drastically different car seat.
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.
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.
Would Ubering with something like this work?
