I read this in the '80s in a school text book. It was either only a couple of pages long, or it was an excerpt. This version included an illustration (that may or may not have been part of the original); this illustration had a Moebius-like style to it.
Plot, at least the way I remember it: man drives through a deserted highway; his car breaks down (?), and he is assisted by a "road guardian" of sorts: a tank-sized vehicle with a humanoid face who comments on how little traffic this road gets and how little work he has to do. That is its purpose: to assist people on the road; but it feels unfulfilled due to the lack of drivers.
The illustration showed a big, tank-like vehicle with a humanoid face embedded, very much like Dumont in the original Tron movie. The illustration was all printed in shades of blue, I think.
