I was sitting in my car on the way home from work the other day, stuck in traffic, bored out of my mind. I was thinking to myself, I could fly past all these cars and be home in 15 minutes if everyone just moved to the side of the road. An unoriginal notion, I’m sure. Alas, I was stopped at a traffic light, unable to move. Then I thought, how strange it is that everyone accepts the authority of a traffic light, and that thought made me wonder how that came to be (hey, better than thinking about the traffic itself). As it turns out, its origin had a dim start.

Like most things in history, it’s very difficult to determine for certain who invented the traffic light first. In 1868, a semaphore signal was invented in London and used red and green lights attached to arms which were controlled by police officers to manage the flow of traffic. Like this one:

Courtesy of http://www.londonremembers.com/subjects/first-traffic-lights-in-world

One year later, a traffic signal exploded due to a leak in a gas line and it severely injured the policeman who was operating the semaphore. To no surprise, the method was discontinued immediately. But (near) death begets life, and a new system arose.

The tri-colored traffic signal we use today was based on the semaphore method that was used for directing railroad traffic. Red lights were used to indicate danger, white lights indicated safety, and green lights indicated caution. Wait, doesn’t green mean go? That phrase is so ingrained in our society, it seems strange that the color would have a different meaning. Well, since red has generally always been a sign of danger, transportation officials decided to keep red as the universal color for warning. Green was most likely chosen to signify caution because it is vivid, yet contrasts red nicely without being distracting. With that in mind, it’s obvious that a method for directing rail road traffic was necessary, but why did it become necessary to direct street traffic?

At the beginning of the 20th century in America, automobiles were just being invented. Granted, they were rudimentary, but a machine nonetheless. Add pedestrians, horses, horse drawn carriages, and bicycles to the mix, and the streets were filled with a chaotic surge of traffic. If only there was a way to control the congestion…

In 1912, a Utah policeman named Lester Wire developed a traffic signal, sort of. His apparatus was a handmade wooden box with red and green lights on a pole that attached to wires which were used for trollies and electric lights. His intentions were noble, but it wasn’t quite advanced enough.

Then in 1914, in the hot spot of Cleveland, Ohio, the first electric signal was installed. It was based on an invention created by a man named James Hoge. His system contained just two colors, red for stop and green for go, which were mounted on four corners of an intersection. It was wired to a manually operated switch Hoge got a patent for his “Municipal Traffic Control System” in 1918 and his invention is often considered to be the first electric traffic signal.

However, there is some dispute. There are other inventors who are credited for creating the first electric traffic signal, but for the most part, inventors improved upon Hoge’s design. A Detroit policeman named William Potts developed a the first four-way tri-colored traffic signal using red, green, and amber lights. In 1923, Garret Morgan, the son of two former slaves, designed a T-shaped traffic signal that resembled a semaphore. One thing is for certain: by 1920, an amber colored light was used in most traffic signals to indicate that the light was about to change.

Garrett Morgan’s patent for his traffic signal

As simple as traffic lights are (it’s only a mechanism of 3 colored lights, after all), we all accept their authority because they work! And we as a society have to give ourselves some credit for all agreeing that it’s better to wait our turn and avoid an accident than rush to our next location in disarray.  Next time I’m sitting in traffic, instead of getting irritated and cursing the poor guy in front of me, I will let my mind wander peacefully and think about the topics of my next blog posts.

Did you find this interesting? Want to read about something else? Comment below!


Bailey, Diane. How the Automobile Changed History. North Mankato, MN: Abdo Publishing, 2015. https://books.google.com/books?id=zOIuCgAAQBAJ&pg=PA45&dq=history+of+traffic+lights&hl=en&sa=X&ved=0ahUKEwiC1PrrytzJAhWGOj4KHZP1CpQQ6AEIRzAH#v=onepage&q=history%20of%20traffic%20lights&f=false.

Berkin, Carol, Christopher L. Miller, Robert W. Cherny, and James L. Gormly. Making America: A History of the United States. 6th ed. Vol. 2. Boston: Wadsworth Cengage Learning, 2012. https://books.google.com/books?id=MXcIAAAAQBAJ&pg=PT240&dq=history+of+traffic+lights&hl=en&sa=X&ved=0ahUKEwj13sWjy9zJAhUMaD4KHX_xAE04ChDoAQgkMAA#v=onepage&q=history%20of%20traffic%20lights&f=false.

Curley, Robert, ed. The Complete History of Railroads: Trade, Transport, and Expansion. New York: Britannica Educational Publishing, 2012. https://books.google.com/books?id=idabAAAAQBAJ&pg=PA99&dq=railroad+lights+history&hl=en&sa=X&ved=0ahUKEwjKkfLF79zJAhVGeD4KHS1EAzEQ6AEILzAC#v=onepage&q=railroad%20lights%20history&f=false.