So you want to know more about Traffic Lights, eh?
That's not a problem with so much rich information available in the world today. The traffic light, which is an especially renowned invention, can be seen in almost every city in the world, in one form or another. With traffic lights all over, it's only a matter of time before you ask yourself, "Where did these crazy useful things come from?"
In this article, we are going to explore the rich birth and history of the traffic signal a.k.a the common traffic light.
In the Democratic Republic of Congo, traffic cops are still in use in five major cities. There's only one real difference they've made in modern times: these cops are Robots. They are designed to swivel at the waste, use articulated arms to direct traffic with red and green lights, and they have recording devices that allow them to report offenders to the proper authorities.
First, the Traffic Control through the ages
Believe it or not, we humans have not be all that diligent in recording "pre-traffic signal" control methods. There are plenty of hypothesis floating around, but it really wasn't until the days of Julius Caesar took up the task, that anyone thought traffic control was really worth documenting. Even then, it wasn't exactly a thorough report, but they did at least highlight a few of the ways in which Rome handled traffic control, which mostly consisted of creating laws that outlawed travel on certain roads by anyone considered "less important" than politicians and other nobleman. It was touch and go trying to control traffic on the rest of the roads, especially since Rome's design of the times was horribly planned, and included openings from all sides of the empire, to allow traffic to flow into one central area, where of course, everyone got log jammed. Because of this, Julius's top minds had to toy with various strategies that could control the flow of incoming traffic from around the continent. They started with a general ban on all wheel based traffic during the daytime, and then began allowing limited numbers of carts and wagons in slowly.
This sort of limited traffic control was really all that existed except in small creative towns that remain undocumented. It wasn't until Leonardo Da Vinci came along with his loveably eccentric ways and began to play with ideas for separating pedestrian traffic from wheel based traffic. His idea was to segregate the two and create separate "byways" for pedestrians, getting them out of the path of incoming wagons and carts. This became a major improvement.
Following this, the first traffic regulation signs came into existence when King Peter II of Portugal had signs manufactured that described which traffic should give way to other traffic; essentially creating the worlds first yield signs.
It wasn't until the 18th century, when trains and railways came into common use, that traffic control received any further sophisication. This was when the first true traffic cops where hired to ensure a proper flow in both directions over the London bridge. There's speculation that traffic police existed before this moment in history, but there are no documented officers with the sole duty of controlling traffic until 1772, when the lord mayor of London created the position. He began with 3 traffic control officers, whose sole job was to make sure all traffic crossing the bridge stayed to the left, creating an easy flow of traffic in each direction.
Traffic control methods began to really take flight after this, bringing forth the first speed limit law in the UK '1832, that designated "furious driving" as illegal. After some time playing with various speed limits for trains, it was determined that 14 miles per hour was the speed achieved when a person rode a horse at a furious speed, and most open roadways were set to that limit, with lower and lower speeds as travelers came into more populated areas.
With the birth of trains and railways came the first true traffic signaling devices, starting with a ball and chain device that "blocked" certain trains onto separate tracks so that other trains could clear the tracks and then allow the blocked trains to disembark as needed. This became necessary when more than one train would use the same tracks within the same day. As more and more trains were used, the sophistication of the signals grew. With those developments, travel by train became that much more popular, which lessened the burden on roads by wagons, but created bottlenecks at train terminals and roads to them.
Then Joseph James Steven's came along and brought the Semaphore signal to the railway. The semaphore was originally invented much earlier as a form of visual telegraph, but for various reasons it never became truly popular for anyone outside of the Navy. True to the original semaphore system, Joseph James's setup created the use of signals that could be interpreted to mean different things to train drivers depending on the color of the signal and the angle the signal was at.
John Peake Knight
Earnest Sirrine's traffic signal
Lester Farnsworth Wire
James Hoge's Traffic Light System
Garrett Morgan, Inventor of the Traffic Signal
The Five Forefathers of Traffic Lights
With horse drawn carriage accidents increasing at an alarming rate in London, John Peake Knight came into the lime light as he created a revolving gas illuminated signaling system that would allow for a traffic officer to control the flow of pedestrians, using a system based on the semaphore used with trains. This grew in popularity until one of them had a gas leak and seriously injured the controlling officer. Knight can be credited as the first to actually invent the traffic "light", since he was the first to illuminate his signals.
By 1870, all of the illuminated signals were removed and in 1910, Earnst Sirrine took up the task of creating better traffic signaling devices for his hometown Chicago. Earnest took things a few steps forward and one step back by removing the illumination and color, then adding words to the signals like "Stop" and "Proceed". Earnst then followed that up with electricity that allowed the signs to be somewhat automated.
A Salt Lake City police detective by the name of Lester Farnsworth Wire was the next forefather to be credited with genuine traffic signal improvements with his version of the electric traffic signal in 1912. Wire was the first to use both colored light bulbs and trolly cables to operate his "birdhouse" traffic light design. These signals could be easily controlled by an officer who held a switch at the bottom of the pole. His design would become the basic design for almost all of our modern traffic lights. Sadly, he didn't patent his design and because of this, many scholars dispute whether he was actually the first to come up with this design.
6 years later, a fellow by the name of James Hoge in Cleveland, patented a new electric traffic signal that he had been perfecting for several years prior. His system made use of more than one bulb of each color and was able to handle more than one direction of traffic by making use of four pairs of red and green lights on a pole that sat on top of a booth. Inside the booth was your faithful traffic control officer, who operated each set of lights to create a smooth flow of traffic.
Last, but certainly not least, we meet a man name Garrett Morgan who lived in Chicago and was a major witness to a horrible traffic accident that prompted him to take up the task of making traffic signals even better. He came up with a traffic signal that could be easily hand cranked by an officer, and then added features like an "All Stop" signal that stopped all flows of traffic before allowing another flow to proceed through the light. Morgan also added a general caution signal when there was no operator at the box, which would later become the "yellow" light and then added bells and whistles to warn of signal changes.
From there on out, more and more folks came out to improve upon the traffic light until it became the signal we know it as today. If you enjoyed this hub, or know something more you'd like to add, please comment below!
machiningdesign on September 13, 2017:
This is very interesting. Thanks for sharing.
OSBERT JOEL C from CHENNAI on September 12, 2017:
Great and informative article