who made the stop light

The stop light (traffic light) doesn’t have a single “inventor” – several people created key versions over time, each adding something important.

Quick Scoop

1. The very first traffic signal (1868 – London)

• In 1868, John Peake Knight , a British railway engineer, designed what is widely considered the first traffic signal, installed near the Houses of Parliament in London.

• It used semaphore arms by day and gas-powered red/green lamps by night, and it was manually operated by a police officer.

• After a gas explosion injured the officer about a month later, the system was removed, so it didn’t kick off widespread adoption.

2. First electric traffic light (1910s – U.S.)

• In 1912, Lester Farnsworth Wire , a police officer in Salt Lake City, built one of the first electric traffic lights using red and green lights on a pole, manually switched.

• In 1914, a system based on James Hoge’s design was installed in Cleveland; it used illuminated words like “Stop” and “Move” and is often credited as the first electric traffic signal to get a patent and real deployment.

3. The three-color stoplight we know today

• In 1920, William Potts , a Detroit police officer, created a four‑way, three‑color electric traffic light (adding the amber/yellow “caution” light) and coordinated signals at busy intersections.

• His work set the pattern of red–yellow–green that became standard in the following decades.

4. Garrett Morgan and the “all-stop” safety idea

• In 1923, Garrett Morgan patented a T‑shaped, electric, automatic traffic signal that introduced a third “position” to stop all directions of traffic before changing from go to stop.

• This made intersections safer by giving drivers and pedestrians a buffer instead of an instant flip from one direction to another.

• He later sold the rights to General Electric, which helped spread the concept more widely.

5. So, who “made the stop light”?

If you’re asking “who made the first stop light ever?”

• John Peake Knight (London, 1868) is often cited for the first traffic signal at all.

If you mean “who made the modern, electric, three-color stoplight?”

• William Potts gets credit for the first four-way, three-color electric signal (red, yellow, green) in 1920.

If you’ve heard about an inventor in U.S. and civil-rights history lessons:

• Garrett Morgan is famous for his 1923 three-position signal that added the all‑directions “stop” interval and greatly improved safety.

You can think of it like this:

• Knight – first traffic signal idea (gas, semaphores).
• Wire & Hoge – early electric stop/go lights.
• Potts – first three-color, four‑way electric system.
• Morgan – patented three-position system with an all‑stop phase.

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