Why are taxis yellow in colour?

In 1907, car salesman John Hertz looked at his surplus of traded-in cars and decided to start a taxi business. Since taxis needed to stand out, the colour yellow was chosen. That was the result of a survey by the University of Chicago which conlcluded yellow was the easiest colour to spot. Hertz’s Chicago Yellow Cab Company was the first cab service to use the now-familiar moniker. In fact, when the entrepreneur established the Hertz Corporation in 1953, he also used yellow in the new logo.

John Hertz, Yellow Cab, Chicago, USA, Hertz’s Chicago Yellow Cab Company, First Cab Service