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Origin of Traffic Lights

08 May 2020

Gas-fuelled Traffic Lights

Traffic lights are located in almost all major junctions in cities and towns around the world to control the traffic flow. Although their purpose is to regulate the flow of traffic, traffic lights came into existence long before cars were invented. A British railway engineer, John Peake Knight, proposed the adapting of railway signalling systems using semaphore arms for controlling the flow of traffic, as a solution to an emerging problem due to heavy traffic caused by horse carriages in the area, and to allow pedestrians to safely cross the roads. On December 10, 1868, the first gas-fuelled traffic lights were installed outside the Houses of Parliament in London. The gas-fuelled lights were manually controlled by a police officer using semaphore arms. During day time, the semaphore arms would be raised or lowered by the police officer, signalling vehicles whether they should proceed or stop. At night, instead of arms, these gas-fuelled traffic lights were used.

The system worked very well until the policeman who is operating the traffic light was severely injured by an explosion due to a leak to one of the gas lines that was supplying the lamps. Because of the accident, the gas-fuelled traffic light system was immediately dropped in England despite its early success.

In the United States, traffic signalling is done by policemen. In the early 1900s, towers had been built to allow officers have a better view of the traffic. During this time, officers could either use red and green lights or simply just wave their arms to let traffic know when to stop or go.

Electric Traffic Lights

In the early 1900’s, technology was developing very quickly, and with the growth of industrialisation and with the invention of cars, the traffic on the roads increased rapidly which signified a need for better traffic system.

The first electric traffic light had only red and green lights, and did not have an amber light like modern-day traffic signals. Instead of an amber light, it had a buzzer sound that was used to indicate that the light would be changing soon.

In 1912, an American policeman, Lester Wire, came up with the idea of the first electric traffic light. These lights were first installed in Cleveland, Ohio, on August 5, 1914.

In 1920, Detroit became the first to use the red, amber, and green lights to control road traffic. A policeman in Detroit Michigan named William L. Potts invented the four-way, three-color traffic signal using red, amber and green lights that were being used in railroad systems. Many inventors eventually come up with different designs. However, most of these traffic lights usually needed a person to push or flip a switch to change the light.

Traffic Lights That Detect Vehicle Honks

In the late 1920s, automatic traffic lights were invented. The first ones were operated by changing the lights at fixed timed intervals. However, this sometimes caused unnecessary waiting for vehicles when there were no vehicles passing from the opposite side of the road. As a solution to this problem, an inventor named Charles Adler Jr. had the idea of inventing a signal that could detect vehicles’ honking and change signals accordingly. A microphone was mounted on a pole at the intersection and once the vehicle stopped, all they need do is honk their horn and the light would change. And to keep people from continually honking in order to change the light, it was set that once the light was tripped it wouldn’t change again for the next 10 seconds.

Computer-controlled Traffic Lights

In the 1950s, with the invention of computers, traffic lights also started to become computerised. The changing of lights was made quicker due to computerised detection. As computers started to evolve, traffic light control also improved and became easier. In 1967, the city of Toronto was the first to use more advanced computers which are capable of better vehicle detection. Thanks to computers, the traffic of a city could now be predicted, monitored and controlled. The computer also monitors the weather and their operation can be changed according to the current weather condition. The lights can also be adjusted in case of emergencies which increases road safety as a result.

Traffic Lights with Countdown Timer

In the 1990s, countdown timers on traffic lights were introduced. These timers are extremely useful for pedestrians to see if there is enough time to cross the intersection, and for drivers to know the amount of time left before the light changes.

As technology advances, traffic signals will continue to improve over time. We cannot tell or predict how far can traffic lights improve or evolve. However, all of these improvements will all be a waste if people are undisciplined and don’t follow traffic rules.

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