Safety Naked to the Eye: History of Traffic Lights
When you were young, you were probably taught how to follow directions. More importantly, you were taught how to do this from visual cues or signs. You were taught that a red sign with big white letters saying “STOP” indicated to stop moving. Further on that, you were taught to associate the color red with ceasing or cancelling. And going off this, it’s complement color, green, means to go or to carry on. Now there’s really nothing saying these colors or symbols have to mean any of this. However, arbitrary ideas and patterns of thought like this are what’s fed to us at the earliest of ages. And it’s done for great reason, our own safety and convenience. This kind of subliminal learning is what makes the innovation of traffic lights so effective.
Before traffic lights, traffic was maintained by people themselves. Officers would be assigned in certain roads to maintain the flow of traffic. This was around the 1700–1800s, so at least it wasn’t during a time period like ours where rush hour is hell. However, the immediate problem with this is the possibility of human error. What if an officer slacked at the job? What if one was out sick? What if they all died in a crazy boat accident? The point is that relying on humans to provide a necessary service to protect and regulate people on a daily and hourly basis was not realistic. So, machines were soon built for this purpose!
The first few traffic lights were built with the thought that traffic itself was getting much, much worse. You’d have streets filled up with horse carriages not knowing when they could go. So, taking inspiration from early railway systems, traditional automobile traffic lights were born. These were powered by gas and still had to be operated by man, but they were a step above what was the system before. Due to how the lighting worked, levers were used during the day and the lights were used at night. Originally, the lights had writing on them as well. They read “Stop” on the red light and “Go” on green. As an early invention, this was likely designed with wanting to instill that idea of these concepts being color coded. Despite the actual technology not even being electrically powered, there’s a lot of computing concepts present in this early stage.
The original traffic light’s biggest downfall was actual power and functionality. There was even an incident where one exploded during operations. Another downside of course is that these lights were only designed with “Stop” and “Go” in mind. With cars and general automobiles becoming more and more readily available to the public, you couldn’t simply have drivers “stop” or “go” on the fly. This also affected the officers who managed the lights themselves. You can’t expect the lights to be changed properly if the lights on every street weren’t all manned at the same time by individual officers. This is when the electric traffic light came to be. It was designed in the US around the early 1900s. They used a yellow light to signify “slow down.” It was also chosen because it was already a super common color involved in train signs that directed the conductor to adjust speeds. This is an example of adapting other design philosophies into other projects.
Another huge innovation came with this step of the traffic light’s history. Traffic lights were now designed with a set timer in mind respective to the kind of street it was in. This way, the lights were more automated and didn’t require supervision from officers anymore. This also gave the traffic system more structure as well. For example, traffic lights that are perpendicular to other lights on the street would be on the opposite schedule of each other to avoid causing accidents where the streets merge. The first error that comes to mind is “what if the lights desync from the pattern and cause an accident?” The designers did think of this and so, they allowed police stations and emergency centers to manage traffic lights from afar. This was a good fail-safe designed in mind if the machinery itself fails.
Even with all of these great innovations, there were still improvements to be made upon the system. For one, the designs used for traffic lights were very bulky and actually blocked in traffic itself. As well, it became harder and harder to maintain the levers used. They were very small and hard to see. Combine the fact that they were already built onto a clunky looking tower and you can tell this lead into accidents. This lead to levers being phased out from designs and the more modern traffic light being designed with a more compact design. This also meant getting rid of extraneous design, like the words on the lights. More was on the way though, because with the rise of computers, traffic was about to be even more automatized.
A new way to gauge traffic came with the technological revolution: pressure plates. Streets were now having pressure plates installed into them to track when a car would approach a light. This would give the lights a more realistic and on the fly schedule as opposed to just having a set schedule to just work off of. It works that when a red light is on, the plates signal the light to change soon when they can tell a car has stepped on it. It also affected the green light, if enough cars were waiting on the opposite side of traffic. The reason this was so effective is because one computer could manage an entire grid of traffic. The power of just one computer made the system work so seamlessly. To this day, this is the traffic system we use.
