### Parking Theory 2013-01-09

It's funny to observe people in their cars. I saw someone wait a good minute and a half for someone to pull out of a spot when a spot was available just two spots further away. You might think that those few steps they saved are totally worth it; but this was a grocery store, which leads into something everyone seems to ignore.

Cart returns significantly affect the distance you need to walk.

Above we have a rough drawing of a parking lot, the cart returns are indicated by the grey horse-shoe shaped object, the numbers indicate the number of meters from the grocery's door. Each letter indicates a shopper who has parked their car in that respective spot

Each shopper must from their car to the grocery store, do their shopping, then walk from the door to their car, load it up with groceries, return the cart at the nearest cart return, and finally return to their car to leave.

The distance walked horizontally will be the same for each trip, so we can exclude those.

Shopper A: 11 meters from car to door, 12 meters from car to cart return.

So the math for A ends up being 11 meters to the door, 11 meters to load the car, 12 meters to return the cart, and 12 meters to return to the car.

```
11 + 11 + 12 + 12 = 46
```

Shopper B: 15 meters from car to door, 8 meters from car to cart return.

```
15 + 15 + 8 + 8 = 46
```

Shopper C: 19 meters from car to door, 4 meters from car to cart return.

```
19 + 19 + 4 + 4 = 46
```

I'm sure you've caught the trend here, A, B, and C all have to walk 46 meters to complete their shopping trip.

The math changes quite a bit when the cart returns are placed more unevenly, and when there are spots further away from the door than cart returns in this example, but as a general rule it's usually best to find a spot that is reasonably close to the door, but also very close to a cart return.

Enjoy your stress-free parking,

Sarah