You Glide Your Finely Tuned Eldorado into the Parking Lot

You glide your finely tuned Eldorado into the parking lot of your favorite fast food establishment and get in the line for drive through service.After screaming your order into the speaker and receiving what you assume is the go-ahead,you proceed to the first window to pay,and then to the second window to pick up this evening's meal,mystery meat between two buns with a large sugar water that has been colored brown and carbonated.As you exit the parking lot,you ponder the vicissitudes of this ________ channel ________ phase queuing system.