History of Traffic Lights Timeline

(1868–Present)

This timeline traces the development of traffic lights from nineteenth-century gas signals to modern computerized and LED systems. More Less

Go to: Timeline | Event List | Key Facts | Directory

Origins and early signals

Traffic lights introduced in London

Dec 1868

Traffic lights were first introduced in London in December 1868 to assist police officers who were controlling traffic. This marked the beginning of the modern effort to manage increasingly busy urban roadways with dedicated signals.

Image source: Traffic light

First red-and-green signals installed

Dec 9, 1868

On 9 December 1868, the first manually operated traffic signals showing a red or green light at night were installed outside the Houses of Parliament in London. The device adapted railway-style signaling principles for street traffic.

London signal explodes

Jan 2, 1869

The pioneering London traffic light exploded on 2 January 1869 because of a gas leak. The explosion injured the policeman operating it and ended the first experiment with illuminated traffic signals.

Early signals differ from modern lights

1875 - 1899

Traffic lights used in the late 19th century were very different from the standardized signals familiar today. Early designs varied considerably in their mechanisms, appearance, operation, and placement.

Global adoption

Traffic lights spread internationally

1880

Despite the failure of London's first traffic light in 1869, traffic lights had spread around the world by 1880. Their adoption reflected the growing pressure to control traffic in expanding cities.

Semaphore signals spread across the United States

1900 - 1919

During the first two decades of the 20th century, semaphore traffic signals modeled on London's device were used throughout the United States. Each state had its own design, so American traffic-control equipment was not yet standardized.

Toledo installs a semaphore signal

1908

Toledo, Ohio, provided an example of the semaphore traffic signals used in the United States in the early 20th century. Its 1908 device illustrates the variety of locally designed systems then in use.

Traffic control tower installed in Paris

1912

In 1912, a traffic-control device was placed on top of a tower in Paris at the intersection of rue Montmartre and boulevard Montmartre. The installation represented an approach in which elevated equipment helped direct traffic at a busy junction.

Wolverhampton trials automated traffic lights

1927

In 1927, Wolverhampton became the first British town to introduce automated traffic lights. The trial took place in Princes Square at the junction of Lichfield Street and Princess Street.

Leeds opens permanent automated signals

Mar 1928

Great Britain's first permanent automated traffic lights opened in Leeds in March 1928. They were installed at the corner of Park Row and Bond Street, following the earlier Wolverhampton trial.

Ashville traffic light enters service

1932 - 1982

Ashville, Ohio, claims to be home to the world's oldest working traffic light. It was used at an intersection of public roads from 1932 until 1982, when it was moved to a local museum.

First traffic light installed in Asia

1949

The first traffic light on the continent of Asia was installed in Haifa, Israel, in 1949. The installation marked the expansion of electrically controlled road signaling into Asian urban traffic networks.

First South Indian traffic light installed

1953

The first traffic light in South India was installed at Egmore Junction in Chennai in 1953. The signal brought automated intersection control to a major South Indian city.

Bangalore installs its first traffic light

1963

The city of Bangalore installed its first traffic light at Corporation Circle in 1963. The installation formed part of the expansion of formal traffic management in Indian cities.

Automation and standardization

Lester Wire develops an electric traffic light

1912

Lester Wire, a policeman in Salt Lake City, Utah, developed the first electric traffic light in 1912. The development moved traffic signaling toward electrically powered devices rather than manually operated or gas-based mechanisms.

Interconnected signals installed in Salt Lake City

1917

Salt Lake City installed the first interconnected traffic signal system in 1917. Six connected intersections were controlled simultaneously from a manual switch, establishing an early form of coordinated urban signal control.

William Potts creates the four-way signal

1920

In 1920, Detroit police officer William Potts created the first four-way, three-color traffic light. The design incorporated the red, yellow, and green arrangement that became fundamental to modern intersection signaling.

Los Angeles installs automated signals

Oct 1920

Los Angeles installed its first automated traffic signals at five locations on Broadway in October 1920. The installation marked a shift from manually operated traffic control toward automatic urban systems.

Automatic timers begin controlling traffic towers

1922

Traffic towers were beginning to be controlled by automatic timers in 1922. Timer-based operation reduced reliance on continuous human control and made signal cycles more predictable.

Los Angeles expands Acme signal installations

1923

By 1923, Los Angeles had installed 31 Acme traffic-control devices. The expansion demonstrated the city's rapid adoption of automated equipment across its street network.

Morgan receives patent for three-position signal

Nov 20, 1923

Patent No. 1,475,024 was granted on 20 November 1923 for Garrett Morgan's three-position traffic signal. The patent documented a traffic-control design with an additional position beyond the simple stop-and-go arrangement.

Image source: Garrett Morgan

First staggered traffic system installed

1926

The first staggered traffic signal system was installed on Sixteenth Street in Washington, D.C., in 1926. The arrangement led to a doubling of commuting speed by coordinating movement along the street.

Twelve-light system invented

1928

The twelve-light traffic signal system was invented in 1928. Its development reflects the continuing experimentation with signal configurations during the period when traffic-control technology was becoming standardized.

Towers and semaphores phased out

1930

By 1930, traffic towers and semaphore signals had been phased out. Their replacement by more compact and automated traffic lights marked a major transition in the design of urban signal systems.

Computerization and LEDs

Computerized traffic control demonstrated in Denver

1952

Denver provided one of the best historical examples of computerized control of traffic lights in 1952. The example showed how computing could be applied to coordinate signal operation.

Silec patent describes traffic-light technology

1957

A patent filed by the Silec Society in 1957 explained the technology associated with this developing traffic-signal approach. The patent represents the period's effort to document and protect advances in signal control.

Toronto adopts advanced vehicle-detection computers

1967

Toronto became the first city to use more advanced computers for traffic signals in 1967. These computers improved vehicle detection, allowing signal operation to respond more effectively to traffic conditions.

Incandescent traffic lamps become more efficient

1980

In 1980, incandescent traffic-light lamps were improved through the use of a lower 12-volt voltage. The changes increased lamp lifetime and reduced energy consumption.

Electro-techs develops the California LED system

1981

The LED traffic-light system was created by Electro-techs in Corona, California. The company had been created by Raymond Deese in 1981, preceding its work on the first LED main traffic light placed in service in California.

Image source: Light-emitting diode

Electro-techs develops the California LED system

Garbarini introduces a commercial LED product

1988

In 1988, Garbarini, a French plant, distributed the first commercial LED product for traffic signaling: an LED repeater called the Design 2000. The product marked an important step toward LED-based traffic equipment.

First LED main traffic light enters service

1989

The first LED main traffic light was put into service in California in 1989. LEDs offered a more efficient alternative to traditional incandescent lamps and helped establish a new generation of traffic signals.

Key Facts

The first known traffic signal was installed outside the British Parliament in London in 1868 and used red and green gas lamps.
The early London signal was operated manually and exploded in January 1869, injuring the police officer controlling it.
Electric traffic lights emerged in the United States in the early twentieth century, with a three-color signal installed in Cleveland, Ohio, in 1914.
William Potts helped develop the first four-way, three-color traffic signal in Detroit in 1920.
Modern traffic lights use LEDs, sensors, timers, cameras, and computer networks to manage traffic efficiently and improve road safety.

Source

This History of Traffic Lights timeline was generated with the help of AI, using information found on the internet.

We work hard to keep these timelines accurate, but mistakes do get through. If you spot one, email us at [email protected] and we'll fix it for future visitors.

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