Friday, December 4, 2009

Red Light Green Light

Warning: This post has nothing to do with gardening, green-life style, or how to make your own detergent.

This post is what happens when you've spent your day in Christmas traffic jams, staring at traffic lights.

Why are traffic lights red, yellow and green? Who decided against orange, white and blue? Or red, white and blue for that matter?

It's things like this - thoughts I mull over while staring at 50 sets of red brakelights, and the all-powerful traffic signals- that drive me nuts until I know the answer.

In case you're the same way, here's the scoop.

It takes a very long distance to stop a train. So the first signal to stop a train was a fire built between the rails. Meanwhile in 1868, London had the first crude gas lantern designed to control carriage traffic. It used red and green glass plates that were operated manually by a policeman. When it exploded, killing the operator, it became the last traffic signal, until electricity was invented in the late 1800's.

One of the first uses for this new technology was an electronic railway signal: green was on top as the universal signal for "all clear"; red was below it, of picked to be the color for "stop", being the same color as the fire that was already used to stop the trains. Then white was added for the lowest signal, as a caution or warning light.

Eventually, in the early 1920s, automobiles had grown to such a volume that traffic was chaotic and out of control. An African American inventor, Garrett Morgan, designed and patented the first electronic traffic light. He chose to use the railway system light colors: red for danger or stop, green for proceed safely, and white for caution. The order was changed, to differentiate the lights from the railway signals.

Trains run on tracks, disregarding street lights. When a white railway bulb burnt out, it was not as big a problem as when a white traffic signal bulb burnt out, causing drivers to mistake the white bulb of the corner street lights for the signal, jamming on their brakes for no reason and thereby inventing the multiple vehicle pile-up.

Several hundred insurance claims later, white was exchanged for yellow, a color associated with sunny warmth and happiness. Now everyone would be happy about stopping for that red light.

Psychologically red creates tension and nervousness in the brain, alerting our thought process that a decision is imminent, while green is soothing and calm.

But I think the immortal words uttered by Jeff Bridges in Starman best explains traffic lights:

"Red light stop, green light go, yellow light go very fast."

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