News
traffic light evolution
The first non-electric gas-lit traffic signal
1868
England, London
The invention of railway signal engineer J.P. Knight
The first electric traffic light
1912
U.S., Utah, Salt Lake City
The invention of policeman Lester Wire
The first four-way and three-colored traffic light
1920
Detroit, Michigan
The invention of a policeman named William Potts
The first double sided traffic light
2016
Armenia, Yerevan
The invention of