Case Study: Service Processes

The following case about a local coffee shop explores the topic of service process design. As you read though the case, think about how the new drive$-$through process can be made into a positive experience for the shop's environmentally$-$minded clientele.

Tree Frog Caf$$ is a new coffee and sandwich shop that features organic products and ingredients. The owners value sustainable business practices and urban design and want to encourage their customers to walk or bike to their store or at least to come in and spend some time with their neighbours $($and$,$ of course, browse the product selection$).$

One challenge the owners face is that the retail site they have chosen came with an existing drive$-$through window system and lane in the parking lot. At first, the owners blocked off and didn't use the drive$-$through system, but their customers have been asking about it$,$ citing the busy parking lot and the convenience of staying in their cars in poor weather. The owners of the Tree Frog Caf$$ have decided to investigate the impact opening the drive$-$through might have on their business and the environment.

Consider a typical busy morning at the Tree Frog Caf$$: about $60$ customers arrive per hour $($the number of arrivals is Poisson distributed$).$ The Tree Frog Caf$$ uses mobile ordering and order kiosks, so that no customers wait before ordering. Instead, all the time they spend waiting and $\text{'}$in service' is spent waiting for the baristas and kitchen to prepare their food and drink order. The caf$$ can prepare one customer's order in an average of $45$ seconds $($service times are exponentially distributed$),$ and only works on one customer's order at a time.

Each customer buys some food and$/$or drinks, with an average profit margin to the caf$$ of $$3$ per customer. Also, $10\%$ of customers will buy a non$-$food product, with an additional average profit margin of $$5$ per purchase. If Tree Frog Caf$$ opens the drive$-$through, they expect that their total number of customers in the morning will increase by $20\%.$ Of this new total, they figure one third will use the drive$-$through. Assume that drive$-$through customers also use mobile ordering, order ahead of time, or that there are enough drive$-$through ordering stations that customers never have to wait to place their order. They only have to wait for the caf$$ to prepare their order. Service times for drive$-$through and walk$-$in customers will remain the same.

Drive$-$through customers buy the same amount of food and$/$or drinks as walk$-$in customers but never order non$-$food products.

The owners of the Tree Frog Caf$$ are considering two approaches to running the drive$-$through. The first is to treat all customers equally, serving them in the order they arrive at the restaurant regardless of whether they are drive$-$through or walk$-$in customers. However, they know that idling cars emit carbon dioxide, estimating that for every $10$ minutes a car idles it emits $0\mathrm{.}5$ kg of carbon dioxide. So the second approach they are considering is to $($quietly$)$ prioritize the drive$-$through customers. In this plan, they would always serve a drive$-$through customer first, even interrupting the service of a walk$-$in customer. The interrupted service of a walk$-$in customer can be resumed once there are no drive$-$through customers waiting. The owners believe this will reduce the idling cars' carbon dioxide emissions without upsetting their walk$-$in customers too much.

Help the Tree Frog Caf$$ decide what to do with its drive$-$through. Which plan makes the most money? Which plan is best for the environment? Can a compromise be found with carbon offsets?

Questions $$ Follow the Case Study Guidelines on Moodle

$1.$ What is the problem$/$issue addressed in the case?

$2.$ Assuming Poisson arrivals and exponential service, perform the following calculations $($see example $7\mathrm{.}1$ on page $226)$ for both in$-$house and drive$-$through examples. Be sure to show your formulas and calculations.

i$.$ Utilization of the service

ii$.$ Average number in the waiting line

iii. Average number in the system

iv$.$ Average waiting time in line

v$.$ Average waiting time in the system, including service.

$3.$ Which plan makes the most money? Which is best for the environment? Be sure to show your formulas and calculations

$4.$ Can a compromise be found with carbon offsets?

$5.$ What is your preferred solution? Give at least two pros and cons to your preferred solution.