Question

During the Coronavirus pandemic, Bobby’s restaurant is only open for drive-through and wants to provide quick service to their customers to minimize the risk of exposure. They currently have assigned one lane to serve the drive-through crowd. Bobby recognizes that having a lengthy line is likely to deter other customers from arriving at the restaurant. Now, Bobby needs to figure out if he needs to open a second drive-through lane or not. He spends a couple of days to observe the patterns of arrival for customers and notes how long it takes for service to be provided to each customer from the time they enter the drive-through lane until they leave. He finds that the average time between the arrivals of customers is about 1 minute with a “give and take” of about 30 seconds (0.5 minutes). He also notices that the average service time is about 45 seconds (0.75 minutes) per customer with a “give and take” of about 45 seconds (0.75 minutes). He estimates the hourly cost of having a queue would be about $15 per customer lost and his cost of opening a new lane would be about $20 per hour. Use excel to display your solution.

1.Should Bobby open up another lane? Does he need another lane, or can his restaurant sustain as is?

2.What would you recommend he should do? HINT: the “give and take” refers to “standard deviation”

Answer 1

Single lane cost :

avg customer arrival rate = 1+/- 0.5 min

avg customer service rate = 0.75+/-0.75 min

Max Time/Customer = 1.75+1.25 min = 3min, therefore Customers catered in 24 hrs = 480 and Total cost per customer =7200$

Min Time/Customer = 1.75-1.25min = 0.5min, therefore Customers catered in 24 hrs = 2880 and Total cost per customer =43200$

Double lane cost:

480$ for 24 hrs .

The cost of building a double lane is too less as compared to cost of maintaining just a single lane and loosing customers. Hence he should go for the 2 lane solution.