Red means Stop, Green Means Go!

I was reading “Go Dogs, Go” (which I would recommend to any parent) to my two year old daughter when we came to the page where a bird is crossing the street and barrage of dogs driving cars are barreling down the road to get to a party in a tree, when the bird yells, “Red means Stop, Green means Go.”  She then looked at me with her inquisitive eyes and asked, “why is green go and red stop?” Not knowing the answer, I had to save face and told her, “Mommy was going to sing her some songs.”  I was saved by misdirection. But that had me thinking of the why is green meant for go and red meant for stop? This lead me down a rabbit hole which lead into some fascinating discoveries and people along the way.

When attacking this I was not sure what I was going to discover along the way but with anything you do find yourself going down rabbit holes and trying not to get sidetracked. I start learning that red has always been associated with danger i.e. fire, blood, The Romans, the devil, the redzone in football when your team is already losing. It also turns out red has longest wavelength of all the colors which enables it to be seen from great distances, best for penetrating areas and situations such as fog or dusty areas, and to top it off is one of softest lights. While green on the other hand has a shorter wave length and more pleasant or is easier on the eye, associated with a more calming influence in life; nature, hope, renewal, St. Patty’s Da, that one I just threw in. But why red and green? Why not orange and blue or two other colors? I carried on with my research and find out that the first traffic light color system originated from navigational lights from old wooden ships. They would use the lights for marking entrances and boundaries for ports and harbors. Red glass was used for making red lanterns, not because it could be seen from great distances or that is best for penetrating through fog, no, science coincidently proved that years later. It was thanks to the abundance of port or wine bottles that was available and readily consumed at the time thanks to love of alcohol. Green glass was also used at the time to make lanterns but because light colored glass would expose the sunlight much easier than a dark colored glass or red colored, the green would alter the liquids integrity, longevity, and taste, therefore not as much green glass was around. This gradually evolved to identify red with port and green with starboard. The fact that having alcohol not only decide but create traffic directions is another just perfect amount of irony.

 Naturally, as time progressed and technology flourished, factory machines took light of this color-coded system and used red to indicate that the machines were off and green that they were running or on. The railroads took inspiration from this and soon adopted the color-coded signal system, but took it a step further by using red as danger, green as proceed with caution and then added white as a third color communicating safety or all is good. At the time colored blubs were not around yet, so colored lenses were used in its place. However, over time lenses would weaken and fall out of place. There was particular case when the red lens dislodged from the socket and what was left remaining was brilliantly beaming white light communicating all is safe to an oncoming train. This caused a massive incident involving two trains in catastrophic collision, because of this unfortunateness the white was replaced with yellow, which brings us to the modern-day traffic light.

Pictured: Lester Wire

As with most firsts, there is debate on who was the very first, who made it better, and who capsized on it. My findings have four different men all contributing in different ways to the traffic light. J.P Knight from London in 1868 can be credited for creating the very first traffic light using a semaphore, an apparatus or device to communicate signals over long distances. However this system was not a success, it only lasted a few years due to it killing the police officers operating it in an explosion. Years later in 1912 Lester Wire, a policeman in Salt Lake City can be credited with the first actual electric traffic light using red and green lights. His invention took inspiration from the railroad lights just like the railroads did from the factories before that, and the factories from the ships.

 Prior to his invention police officers would be standing in the middle of busy intersections on small platforms slightly higher than a kitchen ladder directing two if not four way traffic. You have to remember driving a car at this time was relatively new, there were no laws, no rules, no lanes, no crosswalks, no driving exams, it was pure chaos, think GTA Vice City or San Andres for those of you who know the game. You could do whatever you wanted, wherever you wanted, however you wanted. It has been said that pedestrians in the street were "fair game" if they did not move out of the way fast enough. Pretty much modern day LA.

 Fast forward eight years and some 1,650 miles and we arrive in Detroit where officer William Potts created his three-color, four-way traffic signal. The addition of the amber color light was finally adopted and was for caution, but it was the positioning of it that really made all the difference.  Having the light placed in between the red and green communicated to drivers to slow down as the green light proceeded it and the red was soon to follow. By the mid-1930’s the three-color signal was the ruling standard for all lights and it is still being used today, all of the world.

We now come to Garrett A. Morgan the last of the four musketeers, he might have been late to the game but had an ace up his sleeve. Garrett was already a well established inventor at the time having created hair products and the first proven gas mask, a device so successful the US Government used the blueprints for WWI. His vision started as he was walking down the street and witnessed a horrific accident between a horse drawn carriage and a car at a problematic intersection in Cleveland, after observing what I can only image as absolute carnage, he invented his traffic signal. It was powered by batteries or electricity if available from overhead wires. Much like Potts before him, his too featured three positions, but slightly different; Stop, Go, and an all-directional Stop position were the three positions. The third position paused traffic in all directions before allowing vehicles to proceed on either of the intersection's perpendicular roads. This was a great feature, not only did it enhance safety for motorists at intersections but also made pedestrian crossings safer, as no cars were allowed to move. In addition to the “all stop” he also incorporated noise. By using bells to signal that the traffic signal was changing directions was brilliant, it allowed pedestrians to cross roads with much more confidence and safely. Martin Knopp, associate administrator for the Federal Highway Administration’s Office of Operations is quoted saying, “Consideration of all modes of travel and improving safety for everyone, especially with an emphasis on vulnerable road users, continues in today’s development of traffic control devices,” about Morgan’s traffic stop. The ace up Morgan’s sleeve was that he was the first to apply and acquire not only for a US Patent but a Great Britain and Canadian patent as well, this giving him the ability and upper hand to use and sell his traffic signal nationally and internationally. His traffic management system was used so prominently throughout America that GE purchased it for $40,000 ($709,000 adjusted) and it was not until Potts’ came about with the tricolor lights that eventually took over.

Pictured: Garrett Morgan and his Traffic Light

Today, we still rely on tri-colored lights, sounds, and timers, but traffic signal systems have become much more advanced. Inductive loops now detect waiting vehicles by measuring the metal in cars; moving magnets create an electric current as vehicles pass over, signaling the system that a car is waiting. The traffic lights themselves have improved as well—they are now larger, equipped to be visible in any lighting condition, and use energy-efficient LED bulbs. Many lights also have sensors to detect the strobing lights of EMS, police, and fire trucks, automatically granting them the right of way. However, these advancements come with a cost. A typical traffic light setup ranges from $250,000 to $500,000, with annual maintenance around $8,000. As a result, some cities and towns explore alternatives like stop signs, yield signs, and traffic circles.

Green and Red have become more than stop and go on traffic lights, they have become so mundane, so common in our day to day lives that we don’t acknowledge or realize how important, vital, necessary, and reliant we are on them. They are used in almost all aspects of our lives, all over the world to convey safety and danger without a need for a translator. Paratroopers use them when in a plane prepping for a jump, they are used for measuring oxygen pressure when scuba diving, hospital gauges, fuel gauges, needle gauges, product sales growth, traffic maps, anything you can think of, they have become synonymous as the ying and yang tool for safety and information. Hell Tom Cruise used a stick of bubble gum where half was green and the other half red then yelling, “Red Light, Green Light”, then throwing it on a helicopter at the end of Mission Impossible to save the day. These colors made the impossible mission possible and saved Tom Cruise in the process.  

Eager and waiting for my daughter to wake up, I was now fully ready to answer the question of why Red and Green lights are the ones we use. Once awake I was planting seeds to get her full attention towards me hoping she would ask the question again as I now was prepared. I was asked nothing about colors. Crickets. Nothing. Zilch. It was not until my wife engaged and saw my struggle and gave her a strawberry and green grape then started playing stop and go with eating the fruit that she finally asked me why red and green. Excited but then a calmness came over me and realizing that she was only two and had the attention span of a flea, I simply answered, “because those are pretty colors”, she agreed adding some of her other favorites to the mix and then threw her plate of fruit all over the floor, saying green light Daddy.