101 Years of the traffic light!
Yesterday marked the 101st anniversary of the first electric traffic light signal system, or ‘robots’ as we call them in South Africa! These systems have shaped the way in which we travel.
On 5 August 1914 – some engineers decided to install a pair of green and red traffic lights facing each side of a four way intersection – in Cleveland. Starting out as a simple experiment – this idea has shaped the way roads around the world work and was honoured yesterday in a Google Doodle!
From a technical point of view this traffic light system wasn’t all that impressive, but they allowed police officers to sit in a booth displaying either a red or green light – saving them the risk of standing in the middle of a busy intersection.
This may give you an idea as to why these were so significant – before the emergence of these traffic light systems, intersections were chaotic. Horses, handcarts, merchants, pedestrians and whatever else filled the roadways – enough so that police officers tasked with trying to control the flows of traffic, were scared for their own safety.
Combined with the emergence of cars, which were much faster than these other forms of road travel – an alarming number of deaths and crashes occurred. Prompting further involvement from police departments to get involved.
The first set of driving rules implemented involved sets of traffic circles, one-way streets and pedestrian crosswalks. Although the most significant of these was for drivers making a left turn through an intersection, being required to turn at a hard right angle. This may seem obvious to us now, but clearly many accidents occurred as a result of drivers taking a left turn and driving straight into oncoming traffic!
These rules prohibited soft left turns, requiring drivers to stay in their lane until turning at a hard angle and therefore missing oncoming cars that were turning right. These first driving rules allowed traffic at intersections to flow smoothly for the first time.
At first, police enforced this rule by whistling at cars that cut corners, but in 1904 – the idea of building a small post in the middle of each intersection (marked “C” in the diagram) emerged.
As more and more cars arrived on the roads, standing at the centre of a busy intersection became increasingly dangerous. It also gave police a poor view, leading long lines of traffic to form — sometimes trapping fire trucks and ambulances.
Finally, in 1914, at the corner of Euclid Avenue and East 105th Street — one of the busiest intersections in Cleveland — the city hired the American Traffic Signal Company to implement an enduring system that had been patented by Clevelander James Hoge a year earlier.
Hoge’s original 1913 patent submission, which used lights with words printed on them. Its design was simple: An operator in a booth flipped a switch to illuminate either a red or green light on wires suspended above each side of the intersection.
As Cleveland director of public safety Alfred A. Benesch wrote in 1915:
“It takes the traffic officer out of the center of the street and places him at a corner of the sidewalk and at an elevation from which he can see over the heads of the crowd.”
If a fire engine arrived the traffic operator could throw an emergency switch, clearing the intersection of all traffic and allowing the emergency vehicle to pass.
In 1920, Detroit policeman William Potts introduced the yellow traffic light; soon after, cities such as New York and Philadelphia began introducing lights with linked circuits, allowing many intersections to change at the same moment. Eventually, the traffic light system became the standard control mechanism for busy urban intersections.
If police departments, engineers, and auto enthusiasts hadn’t figured out a way to minimize the carnage, that might never have changed. But they managed to do so, by forcing pedestrians to use crosswalks, writing rules to standardize the flow of traffic, and, crucially, regulating activity at intersections, where a disproportionate amount of accidents occurred.
Source: Vox.com