At Tim Hortons, the odd time I can walk between the cars in the drive thru line, get my coffee inside and walk between the same cars that haven't moved!I see long lines for fast food places (especially dunkin) around here all the time. Most of these places have empty parking lots- my coworker and I sometimes stop for an iced coffee during lunch, and we can walk in, order, and be back in the car in the time it takes 2 or 3 cars (out of a line of 10+) to move through the drive-through.
I tend to walk in anyways, even if there is no line, as usually I could use a walk and a stretch during a long drive. If I'm near work or home, I just wait until I get there for a coffee.