alt Hacker NewsYeah, anyone who has had to work with USPS bar codes should know that internally these are called routing codes, and they come in 5, 9 and even 11 digit variants. The 11-digit one narrows down to a specific delivery point, but even that isn’t enough to derive an address (just enough to know whether you’re looking at the right one or not). Zip+4 codes also change frequently because they aren’t based on locations but on delivery routes and sequencing.
> 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