The first efficient traffic signal was invented in 1923 by Garrett A. Morgan. Garrett A. Morgan was an African- American inventor. As soon as the automobiles were introduced in the 20th century the condition of traffic deteriorated and the roads were full of accidents. There was an urgent need to control traffic, many inventors came forward with their inventions of traffic signals and most of them were manually operated. In 1923 Morgan of Cleveland, Ohio got the patent for his traffic signal. It was a t-shaped rod which managed three activities- stop, go and all stop for all directions. All stop was the time for pedestrians to cross the road safely. This was also a manually operated signal. The rights of his invention were sold to General Electric Corporation by him. It was a good deal that paid him $ 40,000.
Garrett A. Morgan shifted to Ohio at the age of fourteen in search of job. He worked as a handyman for a landowner but continued his studies. In 1895, he moved to Cleveland and there he worked for a cloth manufacturer, repairing sewing machines for him. In 1907, he started his own shop of sewing machine and shoe repair. After two years he set up another business, a tailoring shop which used all the material made by Morgan. His inquisitive nature proved that the liquid used to polish the needle not only straightened the fabric but also hair and this was another invention of his.
I was under the impression that William Potts invented the 3 signal system in 1920. https://en.wikipedia.org/wiki/William_Potts_(inventor)
Steven Bergstrom says
J. P. Knight invented the traffic light in 1868, which wasn’t as efficient as Morgan’s, but should certainly be noted.