William Potts (May 1883 – 1947), a Detroit police officer, is credited with inventing the modern, three-lens
traffic light
Traffic lights, traffic signals, or stoplights – known also as robots in South Africa are signalling devices positioned at intersection (road), road intersections, pedestrian crossings, and other locations in order to control flows of traf ...
in
Detroit
Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at th ...
in 1920. (The two-lens, red/green traffic signal was invented in London in 1868 by
John Peake Knight
John Peake Knight (13 December 1828 – 23 July 1886) was an English railway manager and inventor, credited with inventing the traffic light in 1868.
Biography
Knight was born in Nottingham and attended Nottingham High School. His elementary s ...
).
Biography
William Potts was born in
Bad Axe, Michigan. The
1900 census lists Potts as 17 years old and a police officer. By 1910, he was married to Grace (Baker) Potts, and they subsequently had 4 children. Potts became the 'superintendent, signal person police' for the city of Detroit.
The old system of police directing traffic had become increasing outmoded; two-color signals, with green and red lights, already existed, but they did not leave drivers sufficient time to stop at high speeds. Some municipalities experimented with leaving the green on for a few seconds after the red was illuminated, to caution the driver that the right of way was soon to change. In 1917, Potts devised a new system by inventing a 'yellow' or 'amber' light which would shine after the green light and before the red light to indicate the impending transition.
In 1920, Potts designed the first four-way, three-color traffic signal tower, which was installed at the intersection of Woodward and Michigan Avenues in Detroit in October 1920.
Mr. Trafficlight
''Motor News'', March 1947.
See also
* Traffic light
Traffic lights, traffic signals, or stoplights – known also as robots in South Africa are signalling devices positioned at intersection (road), road intersections, pedestrian crossings, and other locations in order to control flows of traf ...
* Traffic-light signalling and operation
In traffic engineering, there are regional and national variations in traffic light operation. This may be in the standard traffic light sequence (such as the inclusion of a red-amber phase) or by the use of special signals (such as flashing amb ...
References
Humorously referenced in "The Magicians" season 5 episode 5.
External links
* http://didyouknow.org/trafficlights/
* http://signalfan.freeservers.com/historical/pottssig1.htm
1883 births
1947 deaths
Detroit Police Department officers
Traffic signals
People from Bad Axe, Michigan
20th-century American inventors
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