The History and Current Use of Traffic Lights

Traffic signs save lives but what is their history and how do they work today?
Loukia Papadopoulos

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Traffic lights today are crucial to any road infrastructure providing safety and ensuring that all car journeys run smoothly. But have you ever wondered where they come from and how they work? 

The very first traffic light was installed back in 1868, near the Houses of Parliament in London. Unlike today's automatic lights, this one was gas-powered and lit and put out by hand.  

Further lights followed but all of them had one problem: they tended to explode every once in a while. It took till 1914 for the first electric traffic lights (manually operated from a control booth) to be installed in the city of Cleveland, Ohio. 

These lights were missing the yellow shade, however. They were red and green with the third color either being white or an audible buzzer. Why? Because designers followed the same pattern used in railroads.

On railroad tracks, red meant danger and green meant to proceed with caution, so early light designers followed that model. As traffic lights kept being installed people noticed a significant decrease in accidents.

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