James B. Hoge invented the first practical electric traffic light, installed in Cleveland in 1914.
Hoge’s system used electrically operated red and green lights and a control mechanism that allowed police or traffic officers to manage the signals. It was installed at the intersection of Euclid Avenue and East 105th Street in Cleveland, Ohio.
Earlier traffic-control devices existed. London used a gas-lit signal in 1868, and other inventors proposed semaphore or manually controlled systems. Hoge’s contribution was an electrically operated design suited to growing automobile traffic.
Garrett Morgan is commonly associated with a later traffic-signal patent, granted in 1923. Morgan’s design added a warning position, but it did not make him the inventor of the first practical electric traffic light.