I make it a point to avoid drive-through and their idling as much as possible. Turn it off, walk in.

One problem with that is the number of fast-food restaurants and banks that have "only drive through window" hours, while banning pedestrians and cyclists from using the window.

I switched banks to one with the logic to have a well-lit pedestrian window available anytime the drive-through is open. Even though I don't use it too often (ATM 95% of the time) I wish more places would follow suit.

I have never thought about it from a fuel savings stand point. I avoid drive throughs because I hate communicating over those horrible sqwauk boxes. I might dash through one if there are no cars in line, but it is not one of my favorite things. I just prefer to deal with people face to face.