Which of the following is a true statement regarding the properties of queuing diagrams?

The properties of queuing diagrams are fundamental in understanding how systems manage waiting lines, which is critical in civil engineering contexts involving traffic flow, service facilities, and many other applications.

One of the important truths about queuing systems is that the departure rate cannot exceed the service rate or capacity of the server. This principle is rooted in the operational constraints of the service system; if the departure rate were to exceed the service rate, it would imply that the server is providing service faster than it is able to handle, leading to an unstable system.

Cumulative departures can never exceed cumulative arrivals. This suggests that no more entities can leave a system than have entered it, as there is no provision for departures without a corresponding arrival within a defined timeframe. This relationship is crucial for maintaining the integrity of queuing analysis.

Moreover, the slope of D(t), which represents cumulative departures as a function of time, indeed indicates the departure rate. In graphical representation, the steeper the slope at any point in time, the higher the departure rate at that point, reflecting the dynamic nature of the queuing system.

Consequently, all the statements provided reinforce accepted principles of queuing theory. When all statements align with the principles of queuing diagrams, it validates that "