Multiple Server Waiting Line Analysis - Oper Mgmt
CASE STUDY. Multiple server model - waiting line analysis. There are 10 possible alternatives, and the best one must be selected using the information provided. All calculations must be shown (for every alternative), and a thorough explanation of why that design combination was chosen must be included. FOLLOW THE INSTRUCTIONS OF THE ATTACHED JPEG FILE & ANSWER ALL QUESTIONS WITH CALCULATIONS SHOWN.
Atlanta Toll Plaza Design V
The traffic control engineer, Carol Jones P.E., with the City of Atlanta wants to evaluate the design of
one of their highway tollbooth plaza locations. The tollbooths will be configured as either full-service
booths or automated booths. Automated booths take only exact change while a full-service booth
employee will handle credit cards, cash and make change. Carol has to consider that all tollbooth
employees are members of a union, but her main concern is the time drivers spend in the system and
ultimately the total cost of the tollbooth system’s final design.
The tollbooth system must have at least seven tollbooths but no more than ten tollbooths of any
configuration. Due to union rules, the system must have at least six manned tollbooths but in all design
options, at least one of the tollbooths must be an exact change tollbooth. No toll plaza design may
include more than four automated tollbooths.
Ms. Jones knows that the cost to operate an automated tollbooth is $5.00 per hour and $15.00 per hour
to staff and operate a full-service tollbooth. Automated booths can serve 20 cars per minute while full-
service booths can only serve 10 cars per minute on average. Because this is one of the busiest
thoroughfares into and out of downtown Atlanta, it has been determined that it costs passengers
$25.00 per hour if they have to wait at the toll plaza.
Traffic data with respect to the highway site planned for the system is as follows:
1. On average, 60 cars per minute arrive at the planned toll plaza location during the peak driving
hours.
2. lt is known that 15% of drivers arriving at the plaza use exact change. The other drivers need
assistance to pay the toll.
3. Drivers are equally likely to choose any of the respective» tollbooth lanes. This means that
drivers who use exact change choose to join any of the available exact change lanels) without
other preference. Similarly, those who need assistance from a tollbooth collector choose to join
a full-service tollbooth lane without other preference.
4. Once a driver chooses a lane it is impossible to switch lanes because of the volume of traffic at
the toll- plaza.
5. All car arrival and tollbooth service times may be assumed to follow an exponential distribution.
Assignment
Ms. Jones has asked you to write a report that gives a recommendation for the preferred design of the
newest Atlanta toll plaza. In your report make the recommendation with supporting data and
explanation about why the recommendation is the preferred design. Be sure to include any
assumptions made in your analysis and attach the calculations as appendices. Refer to the appendices as
needed to provide support for your report’s recommendation and conclusions.