Originally Posted by
aztimm
I worked at McDonald's in high school and college. We weren't afraid to ask someone to park if their order would take long, then someone ran their food out to them. That kept the main line moving, especially if the following vehicles were getting mostly normal things that were ready.
Culver's and some McDonaldses do that, though some locations have space problems for where to put the cars and still have the drive-thru line moving.
A common problem with that is having too big a menu. Inevitably someone wants some item that has to be dropped in the fryer (or otherwise made ready) and presto, there's the delay.
I won't get in the drive-thru if I see even one car there, but past a certain level (say 4 or 5) it's almost inevitable that doing that will take more time and cause more gas to be burned than going inside.