Fundamental diagram

The fundamental diagram is a graphical representation used in various fields, such as traffic flow or ecology, to describe the relationship between key variables. In traffic, for example, it shows how vehicle density (number of cars per mile) relates to traffic flow (the number of cars passing a point per hour). As density increases, flow rises to a peak, then decreases as congestion sets in. This diagram helps to understand optimal traffic conditions, predict congestion, and improve transportation planning. Essentially, it provides insights into how systems operate under different conditions.