A blog also has it and says "photo courtesy of RAND Corporation".
A search for "RAND corporation self-driving car" led to this report with the image on the cover. Opening the PDF led to this:
Cover image: Advertisement from 1957 for “America’s Independent Electric Light and Power Companies” (art by H. Miller). Text with original: “ELECTRICITY MAY BE THE DRIVER. One day your car may speed along an electric super-highway, its speed and steering automatically controlled by electronic devices embedded in the road. Highways will be made safe—by electricity! No traffic jams…no collisions…no driver fatigue.”
In a perfect world, we never leave our cars. We are just eternally with our friends and family on our racing living rooms. Passing cars deliver your amenities and you simply relieve yourself out the window. The future of a road-only world awaits!
The episode is set five billion years in the future on the planet New Earth, the remainder of humanity on the planet live in perpetual gridlock within the Motorway, a highway system beneath the city state of New New York.
Yeah this looks exactly like a train ride in a corridor coach. Actually it's probably similar to a flight on a golden-age-of-aviation airline too. Crazy what can be done with economies of scale applied to transportation, eh?