The modern stop light doesn’t have a single “creator,” but a few key inventors shaped it into what we know today.

The Very First Traffic Light

  • In 1868, British railway engineer John Peake Knight designed what’s widely considered the first traffic signal, installed near the Houses of Parliament in London.
  • It used semaphore arms by day and red/green gas lamps by night, and a police officer operated it manually.
  • This early signal exploded after a gas leak and was removed within weeks, so traffic lights didn’t immediately catch on.

The First Electric Traffic Lights

  • In 1912, Lester Farnsworth Wire , a police officer in Salt Lake City, created one of the first electric traffic lights using red and green lights mounted on a pole in the middle of an intersection.
  • In 1914, James Hoge in Cleveland patented a “municipal traffic control system” that alternated illuminated “Stop” and “Move” signs at intersections, often cited as the first electric traffic signal system used by a city.

The Three‑Color Stop Light

  • In 1920, Detroit police officer William Potts developed automatic systems that introduced the now-familiar three‑color scheme, adding the yellow (amber) “caution” light.
  • In 1923, Garrett Morgan patented a T‑shaped, three‑position signal that stopped all directions briefly before changing, an important safety innovation and a forerunner of the modern three‑way light.

So, Who “Created the Stop Light”?

If you’re asking “who created the stop light,” people usually mean:

  • First traffic signal at all: John Peake Knight (gas‑lit signal, London, 1868).
  • First practical electric city system: James Hoge (Cleveland, 1914).
  • First three‑color system like today’s lights: William Potts , with a major safety upgrade by Garrett Morgan.

In other words, the stop light evolved over time, and several inventors each contributed a crucial piece of what we now see at every intersection.

Information gathered from public forums or data available on the internet and portrayed here.