Each day the United States Postal Service processes hundreds of millions of pieces of mail and delivers to over 150 million addresses. At the center of this bustling postal network are more than a hundred Processing and Distribution Centers spread across the United States.
This video shows letters, catalogs, magazines, and parcels making their way through these centers. Click the "full-screen" button in the lower right corner of the above video, when playing, to watch full-screen.
When someone sends a letter,
it enters a system already at work
that most people never get to see.
The United States Postal Service processes
hundreds of millions of mail pieces everyday.
The Postal Service delivers almost half the world's mail
to over a hundred and fifty million addresses,
through a network of thousands of post offices.
These offices are supplied by a network of hundreds of
Processing and Distribution Centers around the nation.
The Postal Service separates mail into three categories:
letters, flats, and packages.
Small pieces of mail like letters, bills, and post cards
are all processed by the same set of machines.
Processing letters begins with culling,
or filtering out mail that cannot be handled by
machines down the line due to size, shape, or weight.
Letters then enter the Advanced Facer-Canceller system.
This machine uses specialized cameras
to take pictures of envelopes as they speed by.
These pictures are used by the computer
to find the stamp,
locate the address,
read the handwriting,
and compare the address
against a database of known addresses.
It faces the letter in the right direction,
sprays it with the unique ID tag
and cancels the stamp with a postmark.
The letters are then transferred
to the Delivery Barcode Sorter.
Postal workers feed the letters
into this machine by hand.
This machine sorts letters into "delivery point sequence,"
or the order that postal carriers
will deliver them along their routes.
After letters are sorted,
they are moved to the loading dock.
Customers often bring large bundles of
magazines to distribution centers for processing.
The Postal Service refers to magazines,
catalogs, and similar items as "flats."
Large bundles of flats must be weighed and verified
before they are processed.
They are then taken to a preparation area.
There, they are separated and ready for processing.
After they are prepared, bins of flats go into the Flats Sequencing System,
a machine the length of a football field.
The flat's travel along a conveyor system to a feeder,
where they are removed from the bins
and sent one by one to the scanning system.
A high-speed camera captures images of flats
to identify their delivery addresses.
A computer interprets the scanned addresses
and sends sequencing information
to the machines robotics system.
The flats are then sorted
into delivery order for postal carriers.
Sorted flat so then transfers to trays
and automatically loaded onto carts.
They are then moved to the loading dock.
Package can be particularly difficult
to process by machine
because they come in a wide variety of sizes and shapes.
The Automated Package Processing System
is uniquely equipped to deal with this kind of mail.
Packages are then spread out
as they move along a series of belts and rollers.
As the packages enter the scanning and imaging tunnel,
the machine reads their addresses.
It determines the package dimensions...
checks for proper postage,
and scans the barcode,
updating the package's tracking information.
The packages then travel along a conveyor,
before being kicked off into bins by destination.
Packages are then moved to the loading dock,
where they are loaded onto trucks
along with letters and flats going to the same post offices.
As morning approaches,
drivers deliver the sorted mail
to the appropriate post offices.
After the mail arrives,
postal workers separate it for pickup.
Carriers gathered the sorted letters, flats and packages
to take out on their routes.
Mail delivery connects people and businesses
all across the country.
Everyday technology keeps mail flowing
through this constantly moving network.