The main objective of the yellow lights (used first in military vehicles) was not to be such an easy target.
The Government enacted a law on the 3rd of November, 1936 stating that all vehicles put into production in 1937 are required to have yellow headlights. The French being who they are, didn't abandon these headlights until 1993 when forced by the European Unions conformity standards.
http://www.french-cars-in-america.com/why-did-france-have-yellow-headlights
The color is called 'Selective Yellow'.
ReplyDeleteOriginally optional for automotive applications since the twenties, many countries including North America, Europe, New Zealand and Japan once allowed this in headlights but now only in Fog lights. Today all countries are required to install white in new builds. But most still have a retrospective allowance for prior installations as it was legal at time of manufacture.
The French made this law because of the perceived advantages of Selective yellow. The benefit comes from the filtration of essentially the Blue- violet wavelengths. It was found this band contributed most to the dazzling effect to humans when white light is projected toward the eye in conditions involving rain and snow. It was found Selective Yellow helped with general brightness and clarity with a reduction of glare under these conditions.
Ray-Ban got started in 1937 with green lenses for US pilots reporting headaches from extreme glare. Then in 1938 released their yellow ones for shooters because it "sharpens detail and minimizes haze by filtering out blue light, making it ideal for misty conditions."
Still marketed today as HD Vision eyewear or the equally as stylish clip on visor.