When customers use the drive-thru at a quick-service restaurant, they feel they are entering the fast lane. But maybe that lane isn’t as fast as once thought. In fact, data shows drive-thru service getting slower, specifically 20 seconds slower.

Have you ever wondered what’s driving this speed erosion? And, more importantly, what can foodservice operators do about it? A variety of factors may play a role in the drive-thru slowdown, including:

• A more transient, less trained workforce
• Less labor available due to not being able to find employees
• Less labor deployed due to scheduling challenges that could impact cost and profitability
• Menu innovation slowing customer order times at the menu board
• Menu assembly complexity slowing down the assembly times

As the industry deals with these challenges, the demand for off-premise continues to grow. Off-premise now accounts for 60 percent of all restaurant occasions, according to a study from The National Restaurant Association and Technomic. Naturally, drive-thrus play a key role in off-premise consumption. Which leads one to wonder if an increase in vehicles is contributing to drive-thru congestion, too?

The truth is that consumers have no shortage of options to purchase food they will consume off-premise and some of off-premise may even be more convenient than spending an extra 20 seconds in the drive-thru. And the competition for off-premise sales will only become more intense as operators continue to implement innovative ideas to bring restaurant quality food to a customer’s home or office as they strive to combat flat or declining customer traffic. One example could be the use of drones or robots to deliver food. Third-party delivery companies are testing such ideas today.

So, the only logical response is to enhance speed of service, right? Not so fast my friend.

While speed of service remains an important metric in drive-thru service, throughput is even more important.

Let’s start by explaining the difference between the two:

Speed of service is the measure of time that begins when a customer joins the line until the person drives off. In contrast, throughput represents the rate at which cars move in each period.

If you don’t believe or understand this, visit a Chick-fil-A drive-thru to see art in motion. While your total time in the drive-thru line may be longer than a typical QSR, it may not feel that way since you are moving every 15 to 30 seconds. Further, employees outside of the building engage with you along the way, which helps facilitate the rate of movement. The net impact is a time that’s longer but may feel faster. In addition, the restaurant’s throughput is ginormous.

Try the following exercise, which is about a six-minute drive-thru experience and let me know what you think.

You get in a line that is 12 cars deep (number of cars from start of line to the window) that moves every 30 seconds, compared to a line that is 6 cars deep but moves every 60 seconds. In both scenarios your total speed of service is 6 minutes, but I would contend that the latter example will seem as if the experience took longer. But if this was not enough, in the prior example, the system throughput is 12 cars in the 6-minute period, while in the latter, only 6 cars are served. The net result: 6 more cars of throughput in the same 6-minute period. Is this making sense yet?

We should replace the notion of speed of service with throughput. After all, the greater the throughput the greater the sales. It is not that speed of service is not irrelevant, it is just that throughput is more relevant, and this is how we “show you the money.”

So, what are you doing to drive improve the drive-thru experience? Whether you are a designer, a supplier, or an operator of a brand, what do you have to offer a concept to improve throughput in the drive-thru?