Individuals moving about is usually more organised than “Brownian motion”. After all, Darwinian self-preservation urges us not to collide too often ! But it’s rarely just mass flow or fluid dynamics, as there’s a social and a psychological aspect.
Yes, one can model traffic (or a single vehicle’s mechanical) behaviour with maths. And your machine’s response to your use of its controls will obey physical laws, ensuring consistency. (That’s reassuring, because others may be fickle, sluggish, distracted, unwell). Rely on the great premise of experimental research: “If you always do what you’ve always done, you’ll always get what you always got.”
But we must keep in mind the ultimate logic, that we have control over only our OWN speed and direction, so should plan our movements to absorb others’ misjudgments or inabilities.