Red Light, Green Light: The Science Behind Traffic Signal Systems

Here's a riddle for you: What's green and yellow, but most often red?Give up? It's a traffic light -- you know, those things you hit on your way into the office each morning. But how do they work? And why don't they ever seem to be synced up? Support the show: http://wnpr.org/donateSee omnystudio.com/listener for privacy information.