I learned an expression " Jaywalking is dangerous" in a book.
Is there any other way to say Jaywalking is dangerous?
I will say " Walking across the road without following the traffic signals is dangerous."
But this doesn't sound idiomatic, does it???
I never thought of it as crossing against the red light -- as well as in the middle of the street -- but indeed it is. Here's what the Online Etymology Dictionary says about its origin: jaywalking: by 1912 in Amer.Eng. (said in original citation to be a Kansas City term), from jay, perhaps with notion of boldness and impudence. Related: Jaywalk; jaywalker.
From a Wiki article -- just to prove that Kansas folks like Jays -- The Kansas Jayhawks football program is the intercollegiate football program of the University of Kansas Jayhawks. One assumes they do jayrunning, however.