We barely have aisles in many of NYC's supermarkets and no worries about shopping cart placement in parking lots.We don't have one way aisles in the stores I go to. But, when I go during the elderly & high risk people hour, it's kind of like playing "Human Pac Man." We'll walk to the end of an aisle and look down it. If we see someone already in the aisle, we'll go shop a different aisle until that one clears. And once you start walking down a particular aisle, no backing up or backtracing.
I accidentally did that once, as I realized I passed what I wanted. I turned to back up and there was already a person there, 6ft behind me, waiting for me to move forward. So, I just kept moving forward, instead of being rude and getting in her space. She had politely left 6 ft behind me, until I moved forward, even though I was in the space she wanted to get to. So, I wasn't going to back up. It was my fault that I wasn't looking more carefully in the first place.
When I was a teenager I worked one summer doing inventory counts in supermarkets. They were all in different parts of Long Island and gave me my first look of "real" supermarkets.10 different types of mashed potatoes! An entire aisle of tomato products. Dizzying.