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0 pointsfn-mote18d ago0 comments

> Zip+4 codes also change frequently because they aren’t based on locations but on delivery routes and sequencing.

This was news for me. I know the few zip+4 I memorize never change.

I think the source for the parent is AI slop. See [1].

> Due to an increase in population or to the improve postal operations, the US Postal Service® will occasionally add a new ZIP Code or change ZIP Code boundaries.

The plus four digits encode:

> [67] : Sector or Several Blocks

> [89] : Segment or One Side of a Street

Note that this contradicts the parent.

[1]: https://faq.usps.com/s/article/ZIP-Code-The-Basics

0 comments

twodave18d ago

The census bureau (very) periodically publishes zip code data (which is where some places get their geolocation info). If you work with enough addresses you’ll find some zip+4s that are wildly far away from where they used to be. There are paid services that have better accuracy, but I’m not sure how they acquire their data.

bombcar18d ago

Some people don't realize just how much you can "customize" deliverability with the post office, especially if you're big (like a school or large business) - you can have something that looks like your physical address, but is actually really a maildrop/PO Box at the nearby post office.

You can do relatively complex forwarding that would only appear to the end users if they can decode the barcode.

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