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But Why: A Podcast for Curious Kids

Why does green mean go and red mean stop?

5/1/202636 min

Why is there traffic? How do traffic lights work? How do they know when to turn red and green? Why does green mean go and red mean stop? Why are cars able to go faster than they are allowed to go with the speed limit? Why do we drive on the right side of the road in the United States? Why are some roads bigger than others?  Answers to your traffic questions with Mike Knodler, professor and director of the Transportation Center at the University of Massachusetts.

Download our learning guides: PDF | Google Slide | Transcript

Clips

Inside a Traffic Light Brain
Signals Talk To Each Other
Why Red Is On Top
The Octagon’s Hidden Message
Yellow Doesn’t Mean Floor It
Build More Roads, Get More Cars
Why We Drive On the Right

Transcript preview

First 90 seconds

  1. Speaker 00:00

    Want to help shape future episodes of But Why? Join the But Why Fan Club. Along with other great perks, fan club members now get previews of upcoming episodes and can send questions on the topics we're working on. Beyond the perks, But Why Fan Club members play a big role in supporting our work and help keep this show free for curious kids everywhere. To learn more or join the fan club, head to butwhykids.org/donate. Thanks and stay curious.

  2. Jane Lindholm· Host0:26

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