What's the likely cause for congestion during your commute? Collision? Construction? Guess again. Most congestion is caused by traffic waves, "a phenomenon that’s been exasperating drivers since the first cars started coming off Ford’s assembly line a century ago," writes Matthew Green.
"The simplest explanation for why traffic waves happen is that drivers have relatively slow reaction times: if the car in front of you suddenly slows down, it’ll likely take you a second or so to hit the brakes. The slower your reaction time, the harder you have to brake to compensate and keep a safe distance. The same goes for the car behind you, which has to brake even harder than you did in order to slow down faster. And so on down the road, in a domino-like effect," he explains.
To see this effect in action, play with the interactive visualization created by programmer Lewis Lehe, a civil engineering graduate student at UC Berkeley.