DETROIT — As self-driving cars become increasingly real, automakers are already reimagining how passengers may actually ride in the cars, without the need to pay such close attention to the road.

In at least one case, envisioned by Mercedes, the design would borrow more from the vintage carriages still on the road in “Downton Abbey” than briefcase cars in “The Jetsons.”

The Mercedes F 015 Luxury in Motion concept car, on display at the North American International Auto Show in Detroit, features what the company describes as “four rotating lounge chairs that allow a face-to-face seat configuration.” In other words, the driver (and front passenger, too) can swivel around and make direct eye contact with the people in the back.

This concept actually goes back a long way. Horse-drawn carriages commonly offered vis-à-vis seating for passengers, and it has been a feature of self-driving car fantasies at least since the 1950s. In the late 1960s, Chrysler Imperials could briefly be ordered with an option that included a swiveling front passenger seat and a folding table for on-the-road business meetings — a kind of precursor to the custom conversion vans of the 1970s.