You know the feeling: you're cruising down the freeway when all of a sudden, and without apparent cause, a traffic jam brings you to a standstill. Before long, traffic is flowing again, and you have no idea what triggered the problem. Sure, you have your theories, but wouldn't the whole thing have been far less frustrating if you had had a mathematical model that could explain it? Well, you're in luck, because that's just what a team of mathematicians from the Universities of Exeter, Bristol and Budapest have created. The model "revealed that slowing down below a critical speed when reacting to an [unexpected] event, a driver would force the car behind to slow down further and the next car back to reduce its speed further still."
The end result is that "several miles back, cars would finally grind to a halt, with drivers oblivious to the reason for their delay." While the findings might seem fairly intuitive, they were previously unknown and poorly understood. It turns out that high volumes of traffic are not necessarily the cause of jams; rather, the model demonstrates that "it really matters how hard you brake" when reacting to unfolding events, because a sudden stop in the flow of traffic can cause a chain reaction several miles back. So this holiday season, be sure to drive smoothly. Or, better yet, if possible, take a train, bus, bicycle, or other contraption, and don't drive at all!