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Science in the City
Traffic Signal Science (Clip)
Date: May 25, 2011
Running Time: 00:04:12

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Red means stop, green means go—simple enough, right? But traffic lights are just a small part of the sophisticated science of traffic engineering. San Francisco Traffic Engineer Eddie Tsui takes us on a wild ride through his world, from computer simulations to ever-evolving detection technologies.
Urban environments like San Francisco are full of mysterious natural and human-made phenomena. Why are there so many one-footed pigeons? Where does the sewage go? Why is our “summer” in May and September? The Exploratorium is “taking it outside" to explore these and other questions in engineering, ecology, optics, waves, geology, architecture, weather, and more. Look for new episodes once a month.