Who invented Traffic Light?

Lester Wire, 1912

Who invented Traffic Light ? Traffic lights are a technology with many claims to paternity. If we mean the present red yellow green system, its first appearance was in New York in 1918 or perhaps Detroit in 1920. In all probability, it was in the USA and in response to the growing volumes of traffic as the factories of Henry Ford and others poured out cars cheap enough for the average person to buy.

Attempts to control traffic by signals dated back at least 50 years earlier to a signal post with movable arms like railway semaphores set up to outside parliament house in London in 1868. Red and green gas lamps provided warnings at night, although according to reports the signal blew up after a year of use, killing a policeman and discouraging further experiment.

History of Invention:

The first electric traffic signals, though with only red and green lights, were the work of Salt Lake City policeman Lester Wire in 1912. Placed in charge of the traffic squad, he sought to ease the chaos on the city roads caused by the increasing popularity of automobiles. He also wanted to save fellow policemen from standing in the rain to direct traffic.

Instead they could control the lights from a shelter nearby. Wire refined his system but never patented it, and died having received no royalties.

In 1923 Afro-American inventor and sewing machine repairman Garrett Morgan, patented a cheap and simple traffic control system, using hand- cranked movable arms. This became quite popular, and the myth grew that Morgan had invented traffic signals, which is clearly not so. The US patent office had issued 50 patents before his.

Early systems could be operated either automatically, the lights changing at set time intervals, or manually, controlled by a policeman able to view the state of the traffic and make appropriate adjustments. Not until the 1960s were electronic circuits inserted in the roads to monitor traffic flows, so that the cycling of the lights could be adjusted to minimize delays. From the 1980s, information technology allowed a variety of light change cycles to be applied at any particular intersection as traffic conditions changed, and the succession of lights down a stretch of road to be coordinated.