The first traffic light was installed
England in 1868, long before the invention of cars. It was used
prevent pedestrians from being trampled by the horses. The device
looked like railway signals. Semaphore arms were used in the
but green and red lamps were used at night to represent "caution" and
A policeman had to turn a lever to change the light. The first
traffic lights like those we are using were installed in the 1920's in
Detroit, Michigan, USA.
Source of information: Extraordinary
Behind the Invention of Ordinary Things* by
Don L. Wulffson
*This book is out of print. You
for it in your local library.
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