The history of the first traffic light dates back to December 9, 1868 , in London. This traffic regulation tool, which today is essential for us to manage the number of cars and pedestrians moving through cities, was inspired by gas lamps that were already used on railways.
The British John Peake Knight, precisely a railway engineer, who proposed using two gas lamps, one green and one red , so that it could be seen in the dark. In fact, those colors were already used on railroad tracks due to their intensity and visibility. However, it was a difficult mechanism that, after two months of operation, on January 2, 1869, exploded and caused the death of the operator in London.
As early as 1910, the engineer Ernest Sirrine made improvements to the Peake Knight traffic light: he designed an automatic model with the words stop (stop) and proceed (proceed). The green and red automatic lights were a 1912 occurrence of Lester Wire, a Salt Lake City police officer, and would be patented by William Ghiglieri and installed in the city of San Francisco five years later. The advantage is that the traffic light could be activated or deactivated on purpose by the police, for emergencies. It should be mentioned that this invention was never patented.
The three lights that currently regulate urban traffic around the world were completed when, in 1914, the American police officer William Potts added the color amber, as a transition stage between movement and arrest, at a traffic light in the city of Cleveland.
Finally, in 1936, Charles Marshall devised a rotating traffic light , which showed the seconds remaining before the green signal ends and the red signal appears. However, his invention was unsuccessful: it looked like a watch whose hands ran along the green, red, and briefly yellow signal.
It appears that this model was less intuitive and more difficult to understand. A rotating traffic light model (pictured) is kept in the Melbourne Museum. / WikiCommons.
How did the citizens welcome the arrival of the first traffic light?
Documented testimonies attest that pedestrians initially had great difficulty adapting to this new automatic lighting system. On the other hand, the opposite cannot be expected, as every time a new mill is installed among the population. It was not until the 1920s that the need to develop a traffic manual began to be considered, where it was collected that all road users had the same rights, whether they go on foot or by car, and where human life was considered to be above the right to travel at a certain speed.
Throughout the 20th century, traffic lights evolved. Gas lamps were eventually replaced by led lights, much more efficient and safe. In fact, they consume only 10% of the energy that the old incandescent lamps needed. Now, the traffic light is an essential civic element in cities, which equates the rights and safety of pedestrians and vehicle occupants.
