First Traffic Light..1914

Inventing history:
Garrett Morgan and the traffic signal

In early 1922, African-American inventor Garrett Augustus Morgan designed a cross-shaped traffic signal, for which he submitted a patent application on February 27 of that year. The patent — which was not even among the first 50 traffic signal patents issued in the United States — was granted on November 20, 1923. For whatever reason, numerous writers and public figures have credited Morgan with inventing any or all of the following:

• world's first traffic signal
• first traffic signal to earn a patent
• first automatic traffic signal
• first traffic signal with a third "all-directional stop" phase
• first signal with a yellow light phase
• the basis for modern traffic signal systems

None of these claims are even remotely true, as rest of this page shows.

Myth: Garrett Morgan invented the first traffic signal

Some notable early signals, prior to Morgan's 1922 invention

London, 1868

The first known signal device for regulating street traffic was installed in 1868 in London, at the intersection of George and Bridge Streets near the Houses of Parliament. Designed by railroad signal engineer JP Knight, it had two semaphore arms which, when extended horizontally, meant "stop"; and when drooped at a 45-degree angle, meant "caution." At night, red and green gas lights accompanied the "stop" and "caution" positions (Sessions 1971;Mueller 1970).

By the signal "caution", all persons in charge of vehicles and horses are warned to pass over the crossing with care and due regard to the safety of foot passengers. The signal "stop" will only be displayed when it is necessary that vehicles and horses shall be actually stopped on each side of the crossing, to allow the passage of persons on foot; notice being thus given to all persons in charge of vehicles and horses to stop clear of the crossing.

Proclamation of Richard Mayne, London Police Commissioner, in 1868; quoted in Mueller 1970

Salt Lake City, about 1912

A contender for "inventor of the first electric traffic light" is Lester Wire of Salt Lake City (Sessions 1971).

Mr. Wire, who died in 1958, was a Salt Lake police officer who invented the first electric traffic light in 1912.... The first hand-made model was a wooden box with a slanted roof so rain and snow would fall off. The lights were colored with red and green dye and shone through circular openings. The box was mounted on a pole, and the wires were attached to the overhead trolley and light wires. It was operated by a policeman. In ensuing years, Mr. Wire improved upon the first model.

"Peak Named for Inventor," Deseret News (Salt Lake City), February 9, 1967

Cleveland, Ohio, 1914

On August 5, 1914, several years before Garrett Morgan invented his T-shaped semaphore-type signal, the American Traffic Signal Company installed red and green traffic lights at each corner of the intersection of 105th Street and Euclid Avenue in Cleveland (see this 1914 Motorist article documenting the debut of the lights).

The installation was patterned after the design of Cleveland inventor James Hoge (Sessions 1971; Mueller 1970), whose U.S. patent #1,251,666 describes a system of electrically powered stop-go indicators, each mounted on a corner post. In Hoge's design, the signals are wired to a manually operated switch housed inside a control booth, and are electrically interlocked in such a way as to make conflicting signals impossible. Also described in the patent is a system to allow communication between the signal controller and the police and fire departments. The Cleveland installation incorporated all of the above elements in some form or other, plus a bell to warn the drivers of color changes.

from Hoge's patent #1,251,666

William Potts' 4-way, red-yellow-green signals, Detroit, 1920

In October and December of 1920, a Detroit policeman named William Potts constructed several red-yellow-green light signal systems. Some lights were mounted atop "traffic towers" manned by policemen; others were overhead suspension lamps remarkably similar in form to a modern traffic light. The 4-direction traffic lamp pictured below is of the latter type, and is on display at the Henry Ford Museum in Dearborn, Michigan.

A 1920 vintage Potts signal, at the Henry Ford Museum.

William Potts

An entry in the museum's artifact database describes the item:

The world's first three-color, four-direction, elec. traffic lamp, was installed at the intersection of Woodward Ave. and Fort Street, Detroit, Michigan in October, 1920. It was designed by Superintendent (then inspector) William L. Potts of the Signal Bureau, Detroit Police Department. Basic design remains practically unchanged today. The signal remained in use until 1924 and became a part of the world's first synchronized signal system. This system extended from Jefferson to Adams on Woodward Avenue and was controlled manually from a tower at Woodward and Michigan.

museum archives, Henry Ford Museum & Greenfield Village (as of Jan 29 2003)

The meanings of the colored lights were essentially the same as today. Green meant "go"; red meant "stop"; and yellow (amber) meant "clear the intersection" (Mueller 1970). An analogous color scheme had been used by the railroads, where as early as 1899, the New York, New Haven and Hartford Railroad introduced a system wherein red, yellow, and green meant "stop", "caution", and "all clear" respectively (Brignano 1981).