Foodservice by Design

Team members from PROFITALITY discuss how industrial engineering can be applied to the foodservice industry.

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Keeping Drive-Thrus in the Fast Lane

Over the years, drive-thru as a sales channel has been the cornerstone of many successful quick-service restaurants. During the pandemic, though, the importance of drive-thru sales became even more important when this form of service became one of the only ways customers could get food from restaurants. While all of this may seem alluring to some, never lose sight of the simple fact that a poorly designed and poorly run drive-thru will impact a restaurant’s ability to generate revenue.

ignacio goris 650Ignacio Goris, Labor GuruTo drive home this point, so to speak, let’s say a counter service restaurant takes 10 orders in a relatively short period of time, which ultimately slams the kitchen. While it may take longer than normal to provide the food and a few customers may get frustrated, the fact remains the restaurant still collects the revenue. In the drive-thru, though, if the cars do not move frequently enough, it may cause a backup and deter additional guests from ordering. In this instance, the guests leave frustrated and hungry while the restaurant collects no money.

To help restaurants troubleshoot their drive-thru operations, here is a list of designs and processes that drive-thru operators should review.

The Drive-Thru Timer

Most drive-thru concepts have timers to track performance. Even though they provide valuable information, the use and importance of these timers have been taken out of context. It’s not the speed of service but how many cars an operation can serve during a defined period that will determine whether a concept has a successful drive-thru operation.

Emphasizing only speed of service, in many cases, creates the wrong behaviors. Specifically, instead of processing more cars and providing better service, staff strive to manage the timer.

Let’s say, a concept sets a target of three minutes in the drive-thru as its gold standard. From the time the car joins the drive-thru queue all employees become solely dedicated to that car. With a flow rate of one car every three minutes, the restaurant could only process the transactions from 20 cars per hour, which is very low compared to 60, 120 or 180 cars per hour that successful concepts consistently serve. Other concepts not as focused on the timer, but more on throughput, may not hit the 3-minute time goal, but cars move constantly, and that’s the secret to a successful operation. If a car moves every 30 seconds an operator can expect to process 120 cars per hour. In a 10-car stack, the customer’s time from order to delivery will still be 5 minutes but the guest will be moving constantly.

The ideal drive-thru system is the one in which all key stations work in balance to process the same number of cars or orders. Most systems have three or four stations, depending on whether payment is separate or together with the order pickup. Those stations are:

  • Order taking number per order boards
  • Food production: one or more production lines that get packaged and expedited to be delivered to the car
  • Payment station: stand-alone or part of the pickup window
  • Pickup area: Single window, two-window pickup (the second window for delayed items) or door setup to walk up and down the stack

One of the most critical goals that concepts fail to achieve is having the food and beverage order beat the car to the pickup window. This is the key to keeping everything flowing.

Order Taking

The most common setups have a single order board, which can become the slowest point in the process. Typical order times range from 45 to 75 seconds, which, if no delays develop downstream, could turn into 48 to 80 cars per hour. To accommodate more cars per hour, a concept must add multiple order points. Typical implementation includes a second order board with a dedicated lane, which may require a significant capital investment. A technology-driven solution that many concepts embrace today is arming staff with tablets and dispatching them to take orders from the queued-up cars. This approach allows the operation to open multiple order points, and it breaks the physical barrier of the order post, allowing for order takers to flow through the system, thus creating a larger car stack. 

Food Production and The Car Stack

Food production represents the hardest and most complex section since it includes several moving parts with different cycle times. I will refrain from discussing the production system’s design since that is a much larger issue for another blog. Most relevant to this discussion, though, is the concept of production time. Production equals cooking/assembly time plus packing and expediting time. Given that several workstations may need to simultaneously produce food, any delay at any station will slow the entire system. The total production time must be shorter than the total car stack times during the average non-delay window time. If the production time is slower, the window will have to wait for production.

From a design standpoint, the car stack represents one of the most critical aspects and varies by concept. For example, cook-to-order concepts with 3-to-5-minute cook cycles need a larger car stack compared to concepts that cook, hold and assemble to order or concepts that only expedite or bag the orders on demand. As an example, a concept of cooking to order with a 5-minute cook time plus 30 seconds assembly time and 30 seconds bagging time mean a total production time of 6 minutes, which would need a car stack of 6 to be able to consistently achieve 60 cars per hour. If their stack is only three cars it is unlikely that they could push more than 30 cars unless they pull cars forward. This will not make the restaurant’s speed of service take longer, but it will limit its throughput since there would only be three spots for cars to use while waiting after they place their orders. Since the restaurant needs 6 minutes to produce the orders it will take 2 minutes per car or a maximum of 30 cars per hour.

Window Time: the Achilles Heel of many Drive-Thru Operations

To maximize throughput the food must be ready by the time the guest gets to the pickup window. Staff must quickly collect payment and deliver the food. How quick? industry leaders can do this in 20 seconds or less. Typically, the biggest hurdle is that the food is not ready when the car arrives and when it is ready it takes longer than necessary to hand off the order to the customer. This gets more complex if the operator needs to collect the payment at the pickup window.

The best-designed systems have a bagging area separate from the window so they can work on orders for cars that are not at the window yet. In this scenario, it is the bagger’s responsibility to ensure all items for the next order are ready and that the order next to the register coincides with the next car up.

To keep the system flowing, orders experiencing significant delays due to a production issue need to be pulled up and the order taken to them when ready. Systems with pull-up windows or doors incorporate dealing with these orders into the design and it is recommended for concepts with long production/cooking times. 

Paying for the Orders

At some point in the quest for additional throughput, taking payment at the delivery window will slow the system and adding a payment station prevents some delays that end up costing the system some cars and money. Adding payment stations to the design is important since in an ideal world there is space for one car between the payment and pickup window and at least three to four cars between the payment and order stations.

Breaking the Fixed Station Paradigm

Concepts have pushed the envelope in the drive-thru to achieve throughputs of more than 180 cars per hour, which is physically impossible in a traditional setup given that it takes 7 to 8 seconds for a car to start, clear a station and have the next car arrive, leaving only 12 to 13 seconds to take orders, receive payment or deliver the food. For this to happen, concepts have been breaking tteh physical barriers set up by a drive-thru window, by positioning employees outside and allowing for the flexibility to add more employees if needed and move up and down the car stack to break the sequential aspects of traditional drive-thrus.

These represent just a few areas that are important to consider as you think about drive-thru design. But the most important is to think about it as a system that needs to be in perfect balance for it to flow and achieve the highest possible throughput. There are a few tools that you should use that will help on optimizing a drive-thru design such as capacity planning spreadsheets and computer simulation. Thank you for reading and please drive up!