[scirocco]

A bed. With seat belt :)

[barney54]

In the future cars might be so safe you don't need a seat belt. Another thing that changes with autonomy is a reduction of crash-related features.

[Piskvorrr]

Improbable, unless you can handwave terrain away. (And deer. And malfunctions. And...) There's so many things a car can impact besides other cars that a non-seatbelt in a car is far less likely than cars being replaced by some other form of transport.

[lddemi]

Imagine something like a modern first class cabin with the concept of 180 degree flat bed-seats.