Others have tried to explain it in terms of what is known as chaos theory. They suggest that at certain moments, when a highway is becoming crowded, the flow of cars is so unstable that a major tie-up can arise from something as minor as a single driver riding the brakes a split second too long. One approach likens sudden slowdowns to phase changes, which happen in nature, for instance, when steam turns to water or water to ice. In light traffic, motorists drive as they like. As the road grows crowded, drivers suddenly find themselves being carried along in the traffic stream, moving at a common speed and often unable to change lanes.
People adjust their routes based on yesterday's backups or today's traffic forecasts.
Molecules, moreover, exist to collide into each other. For motorists, that's not so wise. So although physicists often are drawn to traffic because they recognize similarities with their traditional work, it is the human element that makes it so intoxicating. I think it's cool as hell. The paternity of traffic science is widely attributed to Robert Herman, known as the father of the Big Bang because he accurately predicted the microwave echoes of the creation of the universe long before they were detected.