Beatrice Lang
The electric automatic traffic signal has been credited to multiple inventors, including Garrett Morgan, an African-American man born to former slaves, who patented the three-position traffic signal in 1923. The signal revolutionized transportation by adding a “caution” signal to the existing “stop” and “go” alerts, allowing traffic in all directions to stop and intersections to clear. This invention improved safety and traffic flow. However, the first electric traffic light was developed by Lester Wire, a policeman in Salt Lake City, Utah, in 1912, and installed in Cleveland, Ohio, in 1914.
| Characteristics | Values |
|---|---|
| Inventor | Garrett Augustus Morgan, Sr. |
| Birthplace | Paris, Kentucky |
| Birthdate | March 4, 1877 |
| Parents | Former slaves |
| Education | Grade school |
| Occupation | Inventor, businessman, newspaper owner |
| Other Inventions | Gas mask, smoke protector, ironing board |
| Traffic Signal Invention Date | 1923 |
| Traffic Signal Characteristics | T-shaped pole unit with three positions ("Stop", "Go", and "Caution") |
| Traffic Signal Patent | Yes |
| Patent Number | 1,475,024 |
| Patent Date | November 20, 1923 |
| Rights Sold To | General Electric Corporation |
| Sale Price | $40,000 |
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What You'll Learn
Garrett Morgan's three-position traffic signal
Garrett Augustus Morgan, Sr. was an American inventor who developed several commercial products, including the three-position traffic signal, which improved road safety across America. Morgan was born in Paris, Kentucky, in 1877 to formerly enslaved parents. He devoted his life to creating items that made the lives of everyday people safer and more convenient.
Morgan's three-position traffic signal was an important innovation in traffic management. It featured a T-shaped pole with three arms that controlled the flow of traffic through intersections. The third position, or 'warning' position, was an ancestor of today's yellow light. This position stopped traffic in all directions, giving drivers time to stop or get through the intersection safely. This feature made it safer for motorists and pedestrians to navigate intersections.
Morgan's design was also beneficial as it could be produced inexpensively, increasing the number of signals that could be installed. In 1923, Morgan was granted a patent for his three-position traffic signal. This patent was later sold to General Electric for $40,000, equivalent to over $700,000 today.
Before Morgan's invention, traffic signals were manually operated and featured only two positions: 'Stop' and 'Go'. This led to frequent collisions, as there was no interval between the commands. Morgan's innovation addressed this issue and formed the basis for modern-day traffic signals, contributing significantly to the development of Intelligent Transportation Systems.
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The first electric traffic light
The history of traffic lights is closely linked to the growth of the automobile. The first non-electric, gas-lit traffic lights were installed in London in 1868 to control the flow of horse-drawn carriages and pedestrians. Proposed by British railway engineer J.P. Knight, these early traffic lights used red and green gas lamps at night and were manually controlled by a police officer using semaphore arms during the day.
As automobile traffic increased in the early 20th century, the need for more efficient traffic control became pressing. In 1912, American policeman Lester Wire designed the first electric traffic light, which was installed in Cleveland, Ohio, in 1914. This early electric traffic light had just two colours, red and green, and a buzzer to indicate when the light was about to change.
However, these early electric traffic lights still lacked a crucial feature: a clear signal to warn drivers of an impending change from "Go" to "Stop". This shortcoming often led to abrupt stops or vehicles being stuck in intersections. To address this issue, Garrett Morgan, an American inventor, devised a solution: the three-position traffic signal. Morgan's design introduced a third, "Caution" or Yellow signal, which stopped traffic in all directions, allowing intersections to clear and providing time for pedestrians to cross safely.
On November 20, 1923, Morgan was granted a patent for his three-position traffic signal, which revolutionized traffic management and greatly improved safety on American roads. Morgan's invention formed the basis for the modern-day traffic signal and marked a significant step towards the development of Intelligent Transportation Systems.
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Inventor Lester Wire
In 1912, American policeman Lester Wire designed the first electric traffic light. At the time, he was sergeant of the Salt Lake City Police Department's first-ever traffic enforcement unit. Wire was just 24 years old when he came up with the idea for the traffic light, which he installed in downtown Salt Lake City, Utah, where he was born and raised.
The traffic light was Wire's solution to the chaos of automobile traffic in the early 20th century. Motorists could drive however they wanted, turning or stopping anywhere, and pedestrians had to move out of the way at the risk of being hit. Wire's invention was a red and green light system, with red meaning "stop" and green meaning "go". The lights were placed in a box on top of a pole in the middle of the intersection.
Unfortunately for Wire, he never patented his invention and by the 1960s, the original models had been lost. In 1923, Garrett Morgan patented his own three-way traffic light with stop" and "go" signals, as well as a third signal for pedestrians. Morgan eventually sold his patent to General Electric, which began mass-producing traffic lights. Wire's invention, however, played a significant role in the development and adoption of the traffic light in the United States. Replicas of his original traffic light have been built and are on display in Salt Lake City.
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The yellow light
In 1912, American policeman Lester Wire designed the first electric traffic light, which was installed in Cleveland, Ohio, in 1914. This early traffic signal featured red and green lights and a buzzer to indicate an upcoming change. However, it did not include a dedicated caution signal.
The need for a caution light became apparent as traffic increased and intersections became more complex. In 1920, William Potts, a policeman in Detroit, introduced the first four-way, three-coloured traffic lights with yellow lights to indicate an upcoming change. Detroit became the first city to implement this system.
Around the same time, Garrett Augustus Morgan, an American inventor, witnessed a collision between an automobile and a horse-drawn carriage in Cleveland, Ohio. He recognised the problem of abrupt stops and the lack of warning before the "Go" signal switched to "Stop". Determined to improve road safety, Morgan invented a T-shaped traffic signal with three positions: "Stop", "Go", and "Caution". His design allowed traffic in all directions to stop temporarily, providing a window for intersections to clear and pedestrians to cross safely.
On November 20, 1923, Morgan was granted Patent No. 1,475,024 for his three-position traffic signal, which included the yellow "Caution" light. His invention revolutionised transportation and improved road safety across America's streets and roadways, forming the basis for the modern-day traffic signal.
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Traffic lights in Europe
The world's first traffic light was installed in London on December 10, 1868, at the intersection of George and Bridge Street near the Houses of Parliament. Proposed by British railway engineer J.P. Knight, the system was composed of two mobile signs attached to pivoting arms that were manipulated by a lever. The post was topped with a gas-lit semaphore to ensure visibility.
However, the first traffic lights in Europe with electric automation were installed in 1922 in Paris (Rue de Rivoli, Boulevard de Sebastopol) and Hamburg (Stephan Square). The first electric traffic light was developed in 1912 by Lester Wire, a policeman in Salt Lake City, Utah. It was installed by the American Traffic Signal Company on the corner of East 105th Street and Euclid Avenue in Cleveland, Ohio. It had two colours, red and green, and a buzzer, based on the design of James Hoge, to provide a warning for colour changes.
In 1924, the first electric traffic light in Europe was installed at Potsdamer Platz in Berlin. The five-sided traffic light was mounted on a tower and was primarily manual with some automation, requiring only a single police officer to manage it. The traffic light in Berlin was a square tower with a clock at the top and a cabin for the policeman. The lights were red, green, and blue (instead of yellow) as well as white, which indicated that pedestrians could cross the street.
The evolution of traffic lights has continued over the years, with the rise of computers in the 1950s bringing about computerized detection and improved traffic flow. Today, with the advent of self-driving cars and upcoming technologies, researchers are exploring scenarios where traditional traffic signals may become obsolete, with autonomous vehicles communicating directly with each other to navigate intersections safely.
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Frequently asked questions
Garrett Augustus Morgan, Sr. invented the first electric automatic traffic signal.
Morgan's electric automatic traffic signal introduced a third, "caution" signal. This allowed traffic in all directions to stop and intersections to clear, and for pedestrians to cross before traffic started moving again.
Morgan patented his traffic signal on 20 November 1923.
Morgan also invented a gas mask, which he used to rescue several men trapped during an explosion in an underground tunnel beneath Lake Erie.
