Have you ever wondered why traffic lights are red, green, and yellow? While the mysteries of God and consciousness may remain elusive, the story behind traffic lights is firmly grounded in history and science.

The Beginnings of Traffic Control
Before traffic lights, intersections relied on police officers manually directing vehicles. This system was inefficient and prone to mistakes, paving the way for a better solution.

The Red-Green Gaslight Era (1868)
John Peake Knight introduced the first traffic signal in London, combining red and green gaslights with mechanical arms to manage traffic. This "Semaphore" was innovative but flawed, leading to its eventual replacement by electric signals.

Electric Traffic Signals Take Over
In 1912, Lester Wire in Salt Lake City installed the first electric traffic signal. It retained the red-green concept but lacked automation and the now-familiar yellow light. Police officers had to manually switch the signals.

Enter the Yellow Light (1920)
William Potts of Detroit added a yellow phase to address accidents caused by abrupt red-green transitions. This innovation gave drivers a chance to slow down, significantly improving traffic flow and safety.

The Science Behind the Colors
Why red, yellow, and green? It’s all about visibility. Red has the longest wavelength, making it visible from greater distances. Green and yellow were chosen for their contrast and effectiveness in conveying caution and permission.

Thanks to years of ingenuity and a bit of physics, traffic lights have become a universal language for road safety!