The first traffic signal was invented by J. P. Knight, a railway signaling engineer. It was installed outside of the Houses of Parliament in London in 1868. At that time traffic signals looked more like the railway signals used during that time with "waving semaphore arms and red-green lamps, operated by gas for night use. Unfortunately, it exploded less than a month after being installed, killing a policeman. The accident discouraged further development until the era of the internal combustion engine." The modern traffic light is an American invention.
By the 1890s, traffic control was beginning to be a necessity. Earnest Sirrine from Chicago patented the first automated traffic control system in 1910. His system utilized the words STOP and PROCEED but neither were illuminated and were often difficult to read. Red-green systems were installed in Cleveland, Ohio in 1914. Three-color systems were installed in New York City in 1918 and were manually operated from a tower in the middle of the street. The first true traffic signals installed in London happened in 1925. Those signals were manually operated by a policeman using switches and were located at the junction of St. James's Street and Picadilly. In the first two decades of the 20th-century semaphoric traffic signals like one in London were widely used across the United States and each state had its own design of the device. The City of Paris, a traffic control device was placed atop a tower at the Rue Montmartre and Grande Boulevard. This tower signal was manned by a policewoman and she operated a revolving four-sided metal box on top of a glass showcase where the word "Stop" was painted in red and the word "Go" painted in white. The first vehicle-actuated signals in Britain occurred in 1932 but by some strange quirk of fate were also destroyed in a gas explosion.
An electric traffic light was developed in 1912 by Lester Wire, a policeman in Salt Lake City, Utah, who also used red-green lights. On 5 August 1914, the American Traffic Signal Company installed a traffic signal system on the corner of East 105th Street and Euclid Avenue in Cleveland, Ohio. It had two colors, red and green, and a buzzer, based on the design of James Hoge, to provide a warning for color changes. The design by James Hoge allowed police and fire stations to control the signals in case of emergency. The first four-way, three-color traffic light was created by police officer William Potts in Detroit, Michigan in 1920. Ashville, Ohio claims to be the home of the oldest working traffic light in the United States, used at an intersection of public roads from 1932 to 1982 when it was moved to a local museum.
This is probably way more than you wanted to know about the humble traffic light. But it will certainly give you something to think about the next time you are impatiently waiting for that red light to turn green.
Tomorrow is National Joygerm Day and I hope you'll stop back by for a look at joy and why it's contagious. It's the one gem you'll want to spread to everybody! Until then, I wish you