You might have stopped at a few today. A red stop sign. But why red?
They weren’t always red, or any color at all actually. Prior to the 1920s they didn’t have any specific color or shape. Then in 1922 they made them yellow octagons. The red faded too quickly so yellow was the best visually.
30 years later in the 50s fade-resistant enamel was invented and they decided to change the signs back to red. They’ve been that way ever since.
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