4

3 vehicles in Queue

1 vehicle

(3 vehicles Waiting)

being

served

5 5

4

3

2

1

Toll Booth

4 vehicles in System

Shorthand notation for queuing model:

x / y / z

x = arrival process (D, M or G)

y = service process (D, M or G)

z = number of servers

Most common queuing model:

M / M / 1

r = l/m