Fast food really is getting slower

If speed is of the essence, you might want to consider delaying your lunch break until the afternoon.

That's when fast-food giants stay truest to their promise of speed, according to a new study. From 2:30 p.m. to 4 p.m., the average wait time at a fast food drive-thru clocked in just north of 173 seconds, according to QSR magazine's annual Drive-Thru Performance Study conducted with Insula Research.

An employee hands a drive-thru customer his food order a McDonald's Corp. restaurant in Oak Brook, Illinois.
Tim Boyle | Bloomberg | Getty Images
An employee hands a drive-thru customer his food order a McDonald's Corp. restaurant in Oak Brook, Illinois.

Right behind this came the breakfast period, where the average wait was nearly 175 seconds.

Both segments are considerably faster than the average wait time of 203.29 seconds across all five parts of the day.

Read MorePizza titans avoid Italy...for now

"I think it's safe to say that the slowdown continues … that drive-thrus do appear to be getting slower," said Sam Oches, editor of QSR magazine.

This year's average time at 23 brands is significantly slower than last year's average of 180.83 seconds, when only seven brands were included.

Vote
Vote to see results
Total Votes:

Not a Scientific Survey. Results may not total 100% due to rounding.

Dialing back the speed has coincided with an increasing number of premium options, which can slow fast-food operators who rely on set processes and relatively simple items for getting food out the door quickly. Still, Oches said the operators surveyed weren't that worried.

"None of them are freaking out about this," he said in a phone interview. "If it does take a couple more seconds to do that, I think they're OK with that."

While operators surveyed weren't that concerned, their corporate heads have discussed speed at length.

Read MoreCouple leaves $100 tip for bad service. Here's why

The need for speed is part of the reason that McDonald's has focused on simplifying its product offerings.

"[I]n addition to making it easier for customers to order their favorite products, this will reduce complexity in our restaurants, which, in turn, should enhance accuracy and speed of service," McDonald's chief Don Thompson said on the company's most recent conference call.

At the beginning of this year, rival Burger King launched the Restaurant Excellence Visit program to improve its operations.

"Since the REV program has been in place, we've already seen tangible results," Burger King executive Alexandre Macedo told analysts recently. "Overall guest satisfaction scores have improved 11 percent and speed-of-service has improved 9 percent, but there is still much room to improve."

In addition to being the speediest, the afternoon time period was the busiest. On average, there were 1.98 cars in line.

Broken down by category, burger chains proved to be the speediest segment, followed by chicken chains and then sandwich chains.

Speed doesn't equal accuracy though, QSR found. Burger chains were the least accurate while sandwich restaurants got orders correct the most often, with an 87.5 percent accuracy rate.