1. CHAPTER 18
Waiting Lines

2. Waiting lines are non-value added occurrences
Disney World
Waiting in lines does not add enjoyment
Waiting in lines does not generate revenue
Waiting lines are non-value added occurrences

3. Waiting Lines
Queuing theory: Mathematical approach to the analysis of waiting lines.
Goal of queuing analysis is to minimize the sum of two costs
Customer waiting costs
Service capacity costs
Waiting lines are non-value added occurrences

4. Implications of Waiting Lines
Cost to provide waiting space
Loss of business
Customers leaving
Customers refusing to wait
Loss of goodwill
Reduction in customer satisfaction
Congestion may disrupt other business operations

5. Queuing Analysis Figure 18.1 Cost Service capacity Optimum Total cost
Customer
waiting cost
Capacity
cost = +
Total cost
Cost
Cost of service capacity
Cost of customers
waiting
Service capacity
Optimum

6. System Characteristics
Population Source
Infinite source: customer arrivals are unrestricted
Finite source: number of potential customers is limited
Number of observers (channels)
Arrival and service patterns
Queue discipline (order of service)

7. Elements of Queuing System
Figure 18.2
Arrivals
Service
Waiting
line
Exit
Processing
order
System

8. Queuing Systems Multiple channel Multiple phase Figure 18.3
Channel: A server in a service system

9. Poisson Distribution
Figure 18.4

10. Waiting line Models Patient Reneging Jockeying Balking
Customers enter the waiting line and remain until served
Reneging
Waiting customers grow impatient and leave the line
Jockeying
Customers may switch to another line
Balking
Upon arriving, decide the line is too long and decide not to enter the line

11. Waiting Time vs. Utilization
Figure 18.6
System Utilization
Average number on time waiting in line
100%

12. System Performance Measured by: Average number of customers waiting
Average time customers wait
System utilization
Implied cost
Probability that an arrival will have to wait

13. Queuing Models: Infinite-Source
Single channel, exponential service time
Single channel, constant service time
Multiple channel, exponential service time
Multiple priority service, exponential service time

14. Priority Model Arrivals Service Waiting line Exit Processing order
System 1 2 3
Arrivals are assigned
a priority as they arrive

15. Finite-Source Formulas
Table 18.6
Average number being served
Service factor
Average number waiting
Average waiting time
Average number running
Number in population

16. Finite-Source Queuing
Not waiting or
being served
Waiting
Being
served J L H U W T

17. Other Approaches Reduce perceived waiting time
Magazines in waiting rooms
Radio/television
In-flight movies
Filling out forms
Derive benefits from waiting
Place impulse items near checkout
Advertise other goods/services

18. Managing Queues by Business Rules
Queuing
QAP9
Managing Queues by Business Rules

19. Waiting Line Management
DWL5
Disney Fast Pass Results/Distributing Queues

20. Fast Pass at Disney’s Animal Kingdom—Statistics
Pilot Queue System
DWL6
Fast Pass at Disney’s Animal Kingdom—Statistics

21. Other Queue Perception Improvers
DWL7
Disney World—Traditional Queue Improvement Methods