Amazon, USPS, and Broken Routing Software

19 April, 2021 - 3 min read

Hello ,

Your package has a delivery exception. We attempted to deliver your package at 4:27 pm on September 20, 2020 in TOWN A, VT 12345 but could not access the delivery location. We will redeliver on the next business day.

We noticed the problem 3 years ago, soon after moving into our house. Initially our packages were getting delivered, but not to us. You see, we live in a small town in southern Vermont on a dead end private road; let's call it Apple Hill. Just one town over, in TOWN B, there is an Apple Hill Road. Note the lack of "Road" at the end of our road name. All the towns in this area share a zip code, so just a few miles apart are unique streets with the combination:

"Apple Hill, 12345"


"Apple Hill Road, 12345"

When our packages started getting delivered to random houses in TOWN B on Apple Hill Road, it was obvious to see how the mistake could be made. While there is no house with our number on Apple Hill Road, TOWN B, the drivers were making their best attempt. The question remained though, why does this only happen on Sundays? At first we thought that the delivery drivers on Sundays were simply less familiar with the routes and didn't know how to find us.

In small town fashion, we talked to the local Postmaster. He graciously retrieved our misdelivered packages himself. They no longer go to the wrong address, but we still have to wait for Monday to get our packages. We learned something interesting: USPS uses different routing software when they are doing package deliveries on Sundays.

This makes some sense, normally the postal workers have the same routes every day because they are required to do both pickup and dropoff at every location. When they are only delivering packages, it's much more efficient to only go where you need to. Something about the way this software works prevents it from correctly routing to our house. Our address basically doesn't exist.

After some searching, I learned that USPS calls this the "Dynamic Routing Tool". Back in 2013, when they made the Amazon contract, they put out a federal solicitation. I've had trouble locating the final contract and awarded bid.

According to our local Postmaster, there is no way for their drivers to provide any feedback on address corrections. I wonder how many other rural households fall through the cracks in this system. While this particular situation is a minor inconvenience, it does beg some questions. Does government use of software have to be equitable? Should there be some kind of universal auditing or feedback mechanism for government use of software? I've reached out to the USPS OIG, and I'll post back here with any updates.


After reaching out to USPS, I received a friendly callback. Their engineering team is looking at it as well as working with Amazon to get it rectified. Hopefully I'll be able to check back in here with details about what the issue is. The fact that they are working with Amazon has me wondering if they helped to provide some part of the Dynamic Routing Tool.

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