1923 - Garrett Morgan of Cleveland invented the first three-position traffic light.
November 20, 1923:
On this day in 1923, the U.S. Patent Office grants Patent No. 1,475,074 to 46-year-old inventor and newspaperman Garrett Morgan for his three-position traffic signal. Though Morgan's was not the first traffic signal (that one had been installed in London in 1868), it was an important innovation nonetheless: By having a third position besides just "Stop" and "Go," it regulated crossing vehicles more safely than earlier signals had.