The world's first ever traffic lights were installed outside the British Houses of Parliament in London on December 10, 1868. The gas-lit traffic signal was operated by a policeman and exploded less than a month later, reportedly injuring its policeman operator.
The world's first-ever traffic lights were indeed installed outside the British Houses of Parliament in London, but the specific date of installation was December 10, 1868. The traffic signal was not electric but was gas-lit and operated by a police officer. It was designed by John Peake Knight, a railway engineer.
The signal had only two colors: red and green. Red indicated "stop," and green indicated "proceed." The gas-powered traffic light was manually operated by a police constable standing in a small hut nearby. The device had semaphoric arms that were manually turned to display the appropriate color.
Unfortunately, the experiment was short-lived. Less than a month after its installation, on January 2, 1869, the traffic signal exploded, injuring the police officer operating it. This early attempt at regulating traffic with a mechanical signal paved the way for the development of more sophisticated and safer traffic control systems that followed in the ensuing years.