They made up the term jaywalking by combining "walking" with the term "jay" which was a slang term for a country bumpkin or idiot from out of town. They hired actors to spread the slur to refer to those out of towners that don't know how to "properly" behave around streets in a modern city. They even paid Boy Scouts to hand out warning cards and staged mock funerals
I suppose it didn’t work that well because as a rule a car or bike hitting a pedestrian is still almost always at fault.
All of this led to the 1928 Model Municipal Traffic Ordinance and notably a lot of laws in LA that shifted the liability to pedestrians instead of motorists.
Today if you "jaywalk" in most of the country you get called an asshole. It was an incredibly successful act of social engineering