History of Traffic Lights

Imagine this: streets filled with horse-drawn carriages and bustling crowds of pedestrians, all zig-zagging without any sense of direction. Believe it or not, this was the scenario before traffic lights entered the scene. Let’s take a look at the vibrant history of traffic lights!

Who invented traffic lights?

Traffic lights are an important staple of modern life. Yet, not many people think about the man behind such an essential invention. John Peake Knight, a railway signal engineer, is credited with the invention of traffic lights. In 1868, this smart inventor came up with an idea! He wanted to make railways safer. He created a traffic signal to help trains pass without crashing. His invention had three arms that pointed in different directions, and also consisted of red and green lights powered by gas. These lights allowed the drivers to see the traffic signal at night.

The very first traffic light was set up in London on December 9, 1868, just outside the Parliament building. Before this, police officers had to control the traffic, which was tough because there were so many horse-drawn carriages crossing Westminster Bridge. The streets were dangerously packed, and pedestrians had to squeeze close to the carriages. However, the new traffic light made things easier and simpler. It had three arms and gas lamps that shone red or green at night. A police officer would stand next to it and use a lever to switch the lights. If the light was green, it meant “Caution,” and red meant “Stop.”

Unfortunately, this early traffic light didn’t last very long. Just a few weeks after it was installed, on January 2, 1869, there was a gas leak, and the lamp exploded, hurting the police officer who was operating it. But wait, the story of traffic lights is not over yet!

The first electric traffic signal

Far away from London, in Utah, USA, in 1912 another clever policeman named Lester Wire had an idea. He got inspired by the red and green lights used on railroads and decided to make a traffic signal for roads. Lester Wire’s design had two lights—red for “Stop” and green for “Go”—and was controlled by switches in police and fire stations.

Then entered William Potts in 1920. He used to work in Detroit, Michigan, and noticed that traffic lights at four-way intersections were a complete mess. They just couldn’t sync up! So, Potts got a little creative. He added a third light: yellow, because it was already a color people saw on stop signs and railroad crossings, signaling “Caution.” That way, drivers would know when to slow down before stopping. Thanks to Potts, traffic lights became much easier to use at busy crossings!

By 1922, big cities across America started setting up traffic control towers with timers. These timers managed the flow of traffic automatically, without the need for constant manual intervention. Now they didn’t need police officers at every corner to flip switches all day long. New York City was the first to install one of these fancy new signals, and soon other big cities like Chicago, Philadelphia, and Detroit followed the trend.

Then came Garrett Morgan in 1923 with a game-changer. He invented a T-shaped pole with three signals: Stop, Go, and a clever new one in the middle—”Slow Down,” like a yellow light. Plus, his design had an all-direction stop signal too, so emergency vehicles could pass through safely. Quite naturally, this was a big hit, and Morgan sold his idea to General Electric for $40,000, which was a huge sum back then! Thanks to these smart inventors, our roads are a lot safer and far less chaotic today.

While John Peake Knight was the first to come up with an idea for traffic lights, the invention of the modern traffic signal is the result of the tireless perseverance and ingenious curiosity of multiple innovators. That is how science works! Someone comes up with an idea and over many years the idea is perfected into its modern version by multiple contributors.

Welcome to the world of modern traffic lights!

Computers have revolutionized almost every single aspect of our lives, and they have transformed the landscape of traffic signals too! In the modern age, traffic lights are equipped with sensors that are able to detect the amount of traffic at any intersection and accordingly provide the appropriate color signal.

Back in the 1950s, for the first time ever, traffic signals were installed that weren’t operated by timing or police inspectors. These smart signals could actually sense the cars on the road, like magic! They made use of six pressure-sensitive detectors to measure how many vehicles were coming and going. Just imagine the very busy road feeling the movement of cars rolling over it, and then deciding when to change the lights. Pretty neat, right?

Smarter and better traffic signals: Adaptive Traffic Control Systems (ATCS)

Ever wish traffic lights were smart enough to know when you’re in a hurry? Meet Adaptive Traffic Control Systems (ATCS)—the traffic lights with a brain! These systems use sensors and clever computer algorithms to adjust signals in real-time to ensure that traffic flows smoothly.

Here’s how they work: ATCS gather data from all sorts of detectors—loops buried under the pavement, cameras, radar, and even connected vehicles (they are quite the traffic spies). They put all this traffic information into algorithms and adjust the lights on the spot. Moreover, they’re always learning, using the data gathered from the detectors to predict future traffic patterns. Yes, they can sometimes predict the future, too!