Traffic LightsThe world's first traffic lights were installed near London's House of Commons (intersection of George and Bridge Streets) in 1868. They were invented by J P Knight.
Among the many early traffic signals or lights created the following are noted:
- Earnest Sirrine of Chicago, Illinois patented (976,939) perhaps the first automatic street traffic system in 1910. Sirrine's system used the non illuminated words "stop" and "proceed".
- Lester Wire of Salt Lake City, Utah invented (unpatented) an electric traffic light in 1912 that used red and green lights.
- James Hoge patented (1,251,666) manually controlled traffic lights in 1913, which were installed in Cleveland, Ohio a year later by the American Traffic Signal Company. Hoge's electric-powered lights used the illuminated words "stop" and "move".
- William Ghiglieri of San Francisco, California patented (1,224,632) perhaps the first automatic traffic signal using colored lights (red and green) in 1917. Ghiglieri's traffic signal had the option of being either manual or automatic.
- Around 1920, William Potts a Detroit policeman, invented (unpatented) several automatic electric traffic light systems including an overhanging four-way, red, green, and yellow light system. The first to use a yellow light.
- Garrett Morgan was issued a patent for an inexpensive to produce manual traffic signal in 1923.