To Whom Is the Law Addressed?

This is not terribly interesting so far. Everyone knows what yellow lights mean before reading this statute. This and other laws function in society reasonably well, even without general public familiarity with their actual statutory formulations. At the same time, formulations seem to play an essential role in certain parts of our legal system.

This presents a puzzle: How is it that the written formulations matter, despite the fact that the citizenry never reads or encounters the formulations directly?