09 December 2015

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Facts History of Traffic Lights Traffic Signals

Facts History of Traffic Lights Traffic Signals

Traffic light is device using which the flow of the people, vehicles and goods is controlled regulated.

Definition of the traffic control –
traffic control is the supervision of the movement of people, goods, or vehicles to ensure efficiency and safety.
Traffic lights also known as traffic signals, signal lights, traffic lamps, stop lights or traffic control signals are signaling devices installed or positioned at the road intersections, crossings to control flow of traffic.

The meaning of colors –
Green – Allows traffic to proceed in the direction
Yellow – Provides warning that the signal will be changing from green to red
Red –Prohibits any traffic from moving, waiting time and must allow others to walk or move, Red must wait.

The world's first traffic lights were installed near London's House of Commons intersection of George and Bridge Streets in 1868. They were invented by J P Knight and constructed by the railway signal engineers of Saxby and Farmer.

The design combined three semaphore arms with red and green gas lamps for night time use, on a pillar, operated by a police constable. The gas lantern was turned with a lever at its base so that the appropriate light faced traffic.

It exploded on January 2, 1869 as result of lean in one of the gas lines underneath the pavement, killing the policeman who was operating it.
After that this system of traffic control was stopped reason – security and safety

In 1912, a Salt Lake City, Utah, police officer named Lester Wire mounted a handmade wooden box with colored red and green lights on a pole, with the wires attached to overhead trolley and light wires. Most prominently, the inventor Garrett Morgan has been given credit for having invented the traffic signal based on his T-shaped design, patented in 1923 and later reportedly sold to General Electric.

The world’s first electric traffic signal is put into place on the corner of Euclid Avenue and East 105th Street in Cleveland, Ohio, on December 9,1914

The oldest electric traffic signal system is on display at a museum in Ashville, Ohio. Its installation cost $1,500 in 1914.

In 1920, yellow light was added to the first electric traffic signal in Cleveland. The traffic signal with yellow light was introduced to other cities including New York and Philadelphia.

The first traffic light with countdown timer was installed in Hampton, Virginia, in 1996. The use of countdown timers was a success in decreasing the number of accidents by 52%.

The first company to add timers in traffic lights was Crouse Hinds. They built railroad signals and were the first company to place timers in traffic lights in Houston, which was their home city.

1722 –
Traffic cops were appointed to control the flow of traffic on London Bridge.
Three men were given the task of directing traffic coming in and out of either London or Southwark. Each officer would help direct traffic coming out of Southwark into London and he made sure all traffic stayed on the west end of the bridge. A second officer would direct traffic on the east end of the bridge to control the flow of people leaving London and going into Southwark.


The first traffic control device appeared near the British House of Parliament at the intersection of George and Bridge Streets. The device was made in response to the desire by a Select Committee to use railway signals on highways. The device had lights and it used arms which extended outwards. It was operated manually by a police officer. The signal was 22 feet high and crowned with a gas light. The light was called the semaphore and had arms that would extend horizontally that commanded drivers to "Stop" and then the arms would lower to a 45 degrees angle to tell drivers to proceed with "Caution". At night a red light would command "Stop" and a green light would mean use "Caution".
The man behind this new and different invention was John Peake Knight a railroad engineer. The main reason for the traffic light was that there was an overflow of horse-drawn traffic over Westminster Bridge which forced thousands of pedestrians to walk next to the house of Parliament.

But Knight’s invention was not to last long. After only a month of use the device exploded and injured the police officer who was operating the light.

In the first two decades of the 20th century semaphore traffic signals, like the one in London, were in use all over the United States with each state having its own design of the device.

One good example was from Toledo, Ohio in 1908. The words “Stop” and “Go” were in white on a green background and the lights had red and green lenses illuminated by kerosene lamps for night travelers and the arms where eight feet above ground. Controlled by a traffic officer who would blow a whistle before changing the commands on this signal to help alert travelers of the change, the design was also used in Philadelphia and Detroit. The example in Ohio was the first time America tried to use a more visible form of traffic control that evolved the use of semaphore. The device that was used in Ohio was designed based on the use of railroad signals.

As Christopher Finch writes in his “Highways to Heaven: The AUTO Biography of America” (1992), the first traffic island was put into use in San Francisco, California in 1907; left-hand drive became standard in American cars in 1908; the first center painted dividing line appeared in 1911, in Michigan; and the first “No Left Turn” sign would debut in Buffalo, New York, in 1916.

Earnest Sirrine of Chicago, Illinois patented (976,939) perhaps the first automatic street traffic system in 1910. Sirrine's system used the non-illuminated words "stop" and "proceed".

Lester Wire of Salt Lake City, Utah invented (unpatented) an electric traffic light in 1912 that used red and green lights.

Based on a design by James Hoge, who received U.S. patent 1,251,666 for his “Municipal Traffic Control System” in 1918, it consisted of four pairs of red and green lights that served as stop-go indicators, each mounted on a corner post. Wired to a manually operated switch inside a control booth, the system was configured so that conflicting signals were impossible.

William Ghiglieri of San Francisco, California patented (1,224,632) perhaps the first automatic traffic signal using colored lights (red and green) in 1917. Ghiglieri's traffic signal had the option of being either manual or automatic.

Around 1920, William Potts a Detroit policeman, invented (unpatented) several automatic electric traffic light systems including an overhanging four-way, red, green, and yellow light system. The first to use a yellow light.

In 1912, a traffic control device was placed on top a tower in Paris at the Rue Montmartre and Grande Boulevard. This tower signal was manned by a police woman and she operated a revolving four-sided metal box on top of a glass showcase where the word “Stop” was painted in red and the word “Go” painted in white. The traffic tower was featured in The Rider and Driver Magazine

The tower was the first innovation that used the three-colored traffic signal and appeared first in the City of Detroit, where the first three-colored traffic light was built at the intersection of Michigan and Woodward Avenues in 1920. The man behind this three-color traffic light was police officer William Potts of Detroit. He was concerned about how police officers at four different lights signals could not change their lights all at the same time. The answer was a third light that was colored amber, which was the same color used on the railroad. Potts also placed a timer with the light to help coordinate a four-way set of lights in the city. The traffic tower soon used twelve floodlights to control traffic and the reason for a tower in the first place was that at the time the intersection was one of the busiest in world, with over 20,000 vehicles daily. The twelve-light system did not become available until 1928 and another feature of the light system was that hoods were placed over the light and each lens was sand-blasted to increase daytime visibility.

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Wednesday, December 9, 2015

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8 comments:

JAMSHED AZMI December 10, 2015  

Oh... A nice post here. Interesting post.

Destination Infinity December 10, 2015  

Didn't know traffic lights have so much history. But I wish people of India show some respect for these traffic lights even when the police is not there to monitor them.

Destination Infinity

lina@happy family December 10, 2015  

My first time to know the history of traffic lights. Interesting.

Bikram December 10, 2015  

wowow .. i had no clue there was so much history behind a simple traffic light .. thank you SM

Bikram's