From the article, this looks like it's for GM's "Cruise" program, which is already out there in limited scope in a couple cities. It's aself-driving car service limited to a small area of San Francisco and.. I want to say Austin?
They're already operating vehicles that are essentially "self-driving" now. This is about rolling out a new class of vehicle using the same technology, but without the human controls.
I don't know a lot about the service, or what, exactly it does, but I suspect it works well because the area the vehicles operate in is extremely limited and the vehicles can have an incredibly detailed, and up-to-date map of that area. I'd also wager the area selected is free of most obstacles and has only one type of terrain, i.e., "downtown low-speed streets" or similar.
That said, I can't imagine the NTSHA will allow a vehicle on the road without any sort of manual emergency control mechanism in place. Though, it may be very rudimentary, like others have suggested, a joystick and a throttle/brake intended to get the vehicle somewhere safe so people can get out.
A lot of science fiction writers try to address the problem of time when humanity becomes a space-faring race. Star Trek has the idea of a "Stardate" and instructed the script writers to just fucking make it up,
Meanwhile, Asimov in the Robots / Foundation universe, everyone still uses the idea of a 365-day / 24-hour day "year", even if no one remembers Earth (except a R. Daneel Olivaw and a few others).
And Kim Stanley Robinson in his Mars trilogy does what OP notes -- Martian years are longer, and the societies diverge pretty rapidly, within a generation, for a whole host of reasons.