The first electric traffic light installed in Cleveland, Ohio, dates to 1914. The American Traffic Signal Company installed it in August at East 105th Street and Euclid Avenue.
The Cleveland installation grew out of experiments with electrically operated traffic control. Lester Wire, a Salt Lake City police officer, developed an electric traffic light in 1912. The Cleveland signal used red and green lights and included a buzzer to warn road users that the signal was changing. Its design was associated with earlier work by James Hoge, whose system allowed police and fire officials to control signals in emergencies.
This was not yet the modern three-color signal. The familiar red-yellow-green arrangement came later. In 1920, Detroit police officer William Potts created the first four-way, three-color traffic light, adding amber as a transition warning between go and stop.
The history is often simplified because several “firsts” overlap: invention, installation, automation, and the first three-color design are different milestones. Cleveland’s 1914 date specifically refers to the installation of an early electric signal there.