Where does this come from, and can I check it?

The mechanical traffic signal introduced a warning caution position between stop and go. The figure is taken from United States Patent and Trademark Office, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a technology fact?

Yes. It sits on the Technology shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Garrett Morgan patented an early automatic three-position traffic signal in 1923

The mechanical traffic signal introduced a warning caution position between stop and go

African American inventor Garrett Morgan received a patent in 1923 for a T-shaped mechanical traffic signal post. His design introduced a warning interval signal to alert drivers that traffic was about to change direction, preventing collisions at busy road intersections. He later sold the patent rights to the General Electric Corporation.

Where this comes from

United States Patent and Trademark Office

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

Go further

Technology trivia History trivia

More facts like this

Alexander Graham Bell was granted the fundamental telephone patent in 1876Bell transmitted the words Mr Watson come here I want to see you across electric wires The pneumatic inflatable tyre was patented by John Boyd Dunlop in 1888Air-filled rubber tubes cushioned road impact to transform bicycle and car transportation Standard railway tracks measure four feet eight and a half inches wideTraditional wagon wheel spacing established global railway track gauge dimensions Escalator steps feature grooved cleats that interlock with end platesInterlocking step grooves sweep debris away at landing terminals for rider safety Escalator handrails move slightly faster than steps for rider safetyCalibrated forward handrail bias stops passenger arms from dragging backward Standard traffic signals arrange red at top and green at bottomVertical light positioning assists colour-blind drivers across international roads

Tags: traffic, transport, inventions

Garrett Morgan patented an early automatic three-position traffic signal in 1923: the short answers

Where does this come from, and can I check it?: The mechanical traffic signal introduced a warning caution position between stop and go. The figure is taken from United States Patent and Trademark Office, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a technology fact?: Yes. It sits on the Technology shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.