Apparently the car used in the 1960s television show was built from a 1955 Ford Lincoln Futura concept car that never worked. So no clue there.
I was thinking about this because I asked my daughter why Batman doesn’t just drive around honking his horn with his eyes closed listening to everything around him. “Robin! That sounds like the Joker!”
Then I realized that I have no idea if I’ve ever seen the batmobile go “BEEP” in the comics or heard the car horn sound in the movies. “BIFF!” “BAM!” “POW!” “HONK?”
I can put “Batman” and “batmobile” tags on this post, but no “car horn”