A manually-controlled gas-powered light-switch on London Bridge was the first traffic signal. It was never popular and, in 1869, exploded and hurt the policeman controlling the switch.
Subsequently, there were countless versions of semaphore lights to control traffic. None gained commercial acceptance.
Morgan, who invented the gas mask, also invented and patented the modern traffic signal. General Electric purchased his traffic signal patent for $40,000 in 1923.
As an African American, Morgan (“the Black Edison”), repeatedly struggled to gain acceptance in business circles.
Morgan lost all his money in 1929, due to the Great Depression. He sought government funds as a reward for a daring rescue in 1916, where he and his gas masks saved the lives of 32 people.
He had been written out of the account due to racism, despite that the town Mayor confirmed his ingenuity and heroinism.