Crowd density (people per square metre) and crowd flow (people per metre per minute) are relalated.
Which converts to the following density versus flow diagram (animated below)
Which is often illustrated as the diagram below.
And can be illustrated using the following space metric (feet and metres)
As density increased flow increases, but only until critical density is reached. This critical density can be different for different events/crowds. As density (people per square metre) increases above the critical density the crowd flow begins to drop. Crowd flow is also a function of the crowd order, armies marching can achieve a greater flow rate at higher densities than a mixed demographic crowd. Order in the crowd can increase the capacity density as the graph below indicates.
