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Traffic Lights Are So Much Weirder Than You Realize

Season 14 Episode 1 | 17m 13s

Why are stop lights red? The common explanation about red light traveling farther through fog is actually wrong. The real story involves early railroads, deadly accidents, an exploding gas traffic light, forgotten inventors, and even the evolution of primate color vision. Here’s how history and biology accidentally created the nearly perfect traffic signal.

Aired: 03/09/26
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