Autopista (Spanish for “highway”) comes from the words auto- (you can guess what that one means!) and pista, which is Spanish for “track” (think, train tracks, or the track that runners run on).
But where does pista come from? The Latin pistus (“to pound” — think of the motion of pounding something into dust as being a bit like the running around the track! Pounding the pavement!). From this Latin pistus, we get a few English words including… pizza (via Italian, of course! Think of the pounding needed to make the pizza dough!) and piston (the piston engine going in circles is a bit like running as well!).
Thus, we can see the p‑st of autopista maps to the p‑zz of pizza and the p‑st of piston.