Given this, answer the following questions:
1. Draw a diagram of the process using the format in Exhibit 7.3.
2. Consider a base case where a customer arrives every 40 seconds and the Customer Service Champion can handle 120 customers per hour. There are two Food Champions, each capable of handling 100 orders per hour. How long should it take to be served by the restaurant (from the time a customer enters the kiosk queue until her food is delivered)? Use queuing models to estimate this.
3. On average, how busy are the Customer Service Champions and the two Food Champions?
4. On average, how many cars do you expect to have in the drive-through line? (Include those waiting to place orders and those waiting for food.)
5. If the restaurant runs a sale and the customer arrival rate increases by 20 percent, how would this change the total time expected to serve a customer? How would this change the average number of cars in the drive-through line?
6. Currently, relatively few customers (less than 0.5 percent) order the Crunchwrap Supreme. What would happen if the restaurant ran the sale, demand jumped on the Crunchwrap Supreme, and 30 percent of the orders were for this item? Take a quantitative approach to answering this question. Assume that the Customer Service Champion never helps the Food Champions and that these two processes remain independent.
7. For the type of analysis done in this case, what are the key assumptions? What would be the impact on our analysis if these assumptions were not true?
8. Could this type of analysis be used for other service-type businesses? Give examples to support your answer.
The following scenario was written by a reporter who became a Taco Bell worker for a few hours to experience what it's like to work in the drive-thru window at one of the most high-tech, quick-serve restaurant chains in the world. As you read, visualize how you could analyze a Taco Bell using the queuing models we discussed in this chapter. After the scenario, we will give you some hints related to how you can model the Quick Service (QS) restaurant and then we will ask you a series of questions related to your model.
It must always be, "Hi, how are you today?" Never, "Hi, how are you?" "Hi, how's it going?" or "Welcome to Taco Bell." Never, "What will it be today?" or, even worse, "What do you want?" Every Taco Bell Service Champion memorizes the order script before his first shift. The folks who work the drive-thru windows at the Taco Bell here in Tustin, California, about 35 miles south of Los Angeles, and everywhere else, are called Service Champions. Those who work the food production line are called Food Champions.