As I stand in line at the checkout lane, shopping cart filled with groceries, I wait for the shopper in front of me to place down the distinct yellow bar behind her groceries as a definitive, nonverbal, mark that she is indeed finished unloading her groceries. It represents and ending and yet a beginning; it is now my turn to transfer all of my groceries to the conveyor. I consider it a race of consideration for my fellow shopper. I must keep up with the movement of the belt and I try to unload everything and stamp down my victory bar behind the Dr Skipper to trade off the never ending relay race of grocery shopping.
The checkout lane divider bars are possibly the simplest interaction one performs at the grocery store but perhaps the most important. The plain plastic bar segments off different buyers' goods, it interacts with the belt movement to halt motion while the previous person pays, and ensures that I don't have to pay for my neighbor's grapes. The bar continues in a seamless circular set of interactions:
1) I pickup my bar from its resting place
2) It rides along with my groceries until its position stops the belt
3) The cashier moves the bar back to its narrow track conveniently pushing its bar brothers further down the line
A perfect yellow bar that can even serve as advertising space, the checkout lane divider bar proves to be a simple yet effective design.
