Mathematics
The Mathematics of Traffic Flow and Queuing Theory
Quick fact
The same mathematics that describes how shock waves form in traffic—called kinematic wave theory—also explains why a minor disruption on a highway can cause a 'phantom traffic jam' that persists long after the cause is gone, a phenomenon observed in real traffic data and modeled with partial differential equations.
Why this is interesting
Have you ever been stuck in a traffic jam that seems to appear for no reason, then vanish just as mysteriously? Why does a single car merging onto a highway create a wave of brake lights that travels backward?