Electric traffic light
Semáforo eléctrico
- Date
- 1912–1914 · confidence high
- Place
- Cleveland, Ohio, United States
- Credited to
- James Hoge (Cleveland, 1914); Lester Wire (Salt Lake City, 1912); William Potts (three-light, Detroit, 1920); Garrett Morgan (1923)
- People
- 👤 John Peake Knight1828–1886
- Field
- Movement
⚠️ Disputed: the sources disagree.
What it is
Electric light signal that regulates a crossing without an officer. Detroit's three-colour version (1920) spread worldwide.
Several US cities claim to have had the first; Garrett Morgan patented a mechanical signal with a caution position.
What it led to
- Traffic engineering and the city adapted to the car
- Automatic control and green-wave signal timing
- Centralised traffic control systems
Built on
- Practical incandescent light bulb1879
- Gasoline automobile1886
- London gas traffic signal (1868)
Made possible
- Centralised traffic control
- Pedestrian traffic light