Atlanta Toll Plaza Design
The air traffic 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 the 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 toll 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 that 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. It 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 as 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 lane(s) without other preference. Similarly, those who need assistance from a tollbooth collector choose to join a full-service tollbooth lane without any other preference.
4. Once a driver chooses a lane it is impossible to switch lanes because of the volume of traffic at the toll booth plaza.
5. All car arrival and tollbooth service times may be assumed to follow an exponential distribution.
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.