Well before Bubb Rubb and Lil’ Sis annoyed their neighbours in aughts Oakland, Edwardian motorists in Britain had Stentophone Whistles to aggrieve their fellow citizens.
Unlike their modern Californian descendants, the neighbours in Olde Scotland need not have feared the constant noise, as the brass original was cable operated: you have to pull a string to get the noise.
Can’t say I’ve managed to find much out about the Stentophone Company and their products other than that those whistles are pretty pricey these days and that they were already an appreciated curio in 1953. The mention in that coronation rally article suggests that people already used them to pimp their Renaults in 1911.
This particular example was attached to an utterly charming 10 hp Swift tourer from 1914.
(Photo credits: tappz at Flickr, CC0)