Even though road signs are as old as the roads (the Romans had already erected bollards out of stone columns along these in order to indicate the distances to Rome), the installation of a real signalling system does not begin until the end of the 19th century. Almost a century after the invention of the first “automotive” vehicle (which “moves by itself”) by the Frenchman Joseph Cugnot, in 1771.
Gas lantern...
Drivers not all being able to read or not reading the language of the country they are traveling through, it is necessary to set up signage without text, made up of pictograms and colors. The very first traffic light was erected in London on December 10, 1868. It was in fact a gas lantern mounted on a steel base 7 meters high. On one side, it is red to say "stop", on the other it is green for "attention". It is turned with a lever. For the record, the agent in charge of its operation was seriously injured when it exploded a fortnight later.
... at traffic lights
But it was in 1914, in Cleveland, USA, that the first electric red light was installed . It is visible from a distance and from any point of the intersection it regulates, and operates fairly summarily:at red you stop, at the bell you start. It was Garrett Augustus Morgan, a sort of “Geo Trouvetout” and inventor, among other things, of the gas mask that saved so many lives during the Great War, who developed it. He also sold his patent to the General Electric Company for 40,000 dollars at the time. On May 5, 1923, this electric red light was installed in Paris at the intersection of boulevards Saint-Denis and Sébastopol, before the green and orange lights - the traffic light that we know - appeared. It has since been one of the major elements in the regulation of automobile, rail and river traffic.