> Back then a 'jay' was basically some sort of boor or doofus. If you translated it to more modern english it would literally be idiotwalking or similar.

If other cultures don’t have some kind of stigmatic word for “crossing the street without pedestrian right-of-way” then of course it is American-specific. Just like how saying “person who has several sexual partners” and “s***” are supposed to communicate two very different things.