US Patent 1,475,024, granted on November 20, 1923, to Garrett A. Morgan of Cleveland, Ohio, is titled simply “Traffic Signal.” It does not describe the first traffic light. What it claims is narrower and more useful: a hand-cranked post that briefly halts every lane of an intersection before giving the right of way to cross traffic.
That gap matters, because one of the most repeated lines in American classroom history says Morgan “invented the traffic light.” The patent itself, which anyone can still read in full, shows an inventor improving a device that already existed. The earlier signals are well documented on both sides of the Atlantic.
Who Garrett Morgan was
Morgan was born in Kentucky on March 4, 1877, to parents who had been enslaved, and his schooling ended after the elementary grades. He reached Cleveland in 1895, fixed sewing machines for a clothing maker, then ran his own businesses: a repair shop from 1907, a tailoring firm that grew to 32 employees, a hair-care company and, from 1920, a weekly newspaper. He was famous before the signal. In July 1916 he and his brother wore his patented smoke hood into a gas-filled water intake tunnel under Lake Erie and carried out trapped men.
The signals that came first
By the time Morgan filed his application, street signals had a half-century of history behind them:
- December 9, 1868, London: railway engineer J. P. Knight’s semaphore, built by the signal makers Saxby & Farmer, went up outside the Houses of Parliament. It stood 22 feet tall, showed red or green from a gas lantern after dark and was worked by a constable with a crank. A gas leak blew it up on January 2, 1869, injuring the officer.
- 1908, Toledo, Ohio: a “Stop” and “Go” arm signal with kerosene-lit red and green lenses, changed by an officer who blew a whistle first.
- 1910s, Cleveland: an electric red-and-green light with a warning buzzer, based on work by Salt Lake City policeman Lester Wire, was installed at East 105th Street and Euclid Avenue, in Morgan’s own city.
- 1917, Salt Lake City: six intersections were tied to a single manual switch.
- 1920, Detroit: police officer William Potts added an amber lamp, producing a four-way, three-color light.
- February 27, 1922, Cleveland: Morgan files application serial number 539,403; it is granted 21 months later.
What the 1923 patent actually adds
The signal described in the patent is mechanical, not electric at heart. A standard carries a box-shaped indicator lettered “Stop” and “Go,” with two pivoting semaphore arms on either side. The first part of a turn of the crank lifts both arms upright, so drivers on every approach see “Stop.” Keep turning and the whole head swings 90 degrees; then the arms drop back to horizontal, cushioned by a small air dashpot, and the traffic that had been waiting gets to go. Two lamps inside the indicator light the lettering at night, and the drawings show optional bells.
Morgan explained the reason for the pause in the patent. Cars caught in the middle of the crossing, he wrote, “are given time to pass the vehicles, which are waiting,” which avoids crashes caused by “the over-anxiety of the waiting drivers, to start as soon as the signal to proceed is given.” He also argued that because the crank handled the sequence, the operator could keep his attention on the street.
The federal highway agency’s history of the device says most signals of the day had only two positions with no interval between them, and that Morgan’s could also be left at half-mast at night as a caution warning. That half-mast setting appears in later accounts, not in the seven claims of the patent.
The honest version of the claim
Morgan did not invent the traffic signal, the electric traffic light or the amber phase. The agency credits him as the first person to apply for and receive a US patent on a three-position signal, while noting that other inventors had tried, and even sold, similar devices. His real contribution was the all-way stop built into every change, which clears the intersection before cross traffic moves; the agency calls his design the basis for the modern signal.
It also paid. He later patented the design in Britain and Canada and sold the rights to General Electric for $40,000. His safety hood, by contrast, lost customers in some Southern cities once newspaper photographs showed that its inventor was Black.
Morgan received a federal citation for the signal shortly before he died in Cleveland on July 27, 1963, aged 86. He is buried in the city’s Lake View Cemetery, and his patent can still be looked up by its number, 1,475,024, with both sheets of drawings attached.
Further reading
- Wikipedia: Garrett Morgan
- Wikipedia: History of traffic lights
- FHWA: Safer Stop and Go: Garrett Morgan’s Traffic Signal Legacy
Image: Unknown photographer, Public domain via Wikimedia Commons
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