According to a recent study done in Seoul, at Soongsil University, most people are stress and alarmed by aggressive car horns.  People would have a more positive reaction to something not as aggressive and starting, like a duck’s quack.

After testing a range of different sounds, the researchers discovered a duck’s quack would work perfectly.

“A group of 100 test listeners evaluated different sounds for qualities including stress and loudness, with the duck noise coming out on top.”

Source: http://metro.co.uk/2017/06/27/car-horns-should-be-replaced-by-duck-quacks-science-says-6738683/