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A professor with a way to reduce time spent at red lights
Attacking a commuting scourge. (Photo: Richard Drew / AP)

You know the routine — wait at one red light, only to meet another at the next intersection, and another. In cities, we are spending 40% of our time idling, according to Stephen Smith, a professor at Carnegie Mellon University. The time adds up: the average American spends 42 hours a year in traffic — almost two complete days, says Inrix, an analytics firm. New Yorkers spend more than twice as long — 89 hours.

Why it matters: Smith says our traffic systems have not changed in a half-century. Down the road, we will have self-driving cars. Before then, though, we can enjoy less road anxiety.