Mr. Big Ideas
I've always thought this was the simplest solution, Dave Thomas (God rest his soul) got halfway there: Weatherproof touchpad to place your OWN order (actually have it your way the right way) display screen showing each item and running total (Duh). Then you drive up, pick up and pay. You see, you don't need a diesel, a vanful of lil' screamers is enough noise for total confusion!!!