This site was created as a
service for all businesses and organizations that have questions about carrier
routes and how they impact direct mailing.
Feel free to have your webmaster create a link from your site directly
to this site and refer your customers here to answer their
frequently-asked-questions. If you've never done direct mail before, you should
check out the great USPS Discount Mailing Services webpage at http://pe.usps.gov/text/dmm200/discount.htm
.
Carrier Route Definitions - see below
ZIP Code FAQ
Mailing by
Carrier Route Mapping - see below
Sample Maps
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A postal carrier route is
the group of addresses to which the USPS assigns the same code to aid in mail
delivery. These codes are 9 digits – 5
numbers for the ZIP Code, one letter for the carrier route type (explained
below), and 3 numbers for the carrier route code. For example
"05055R003" or "12508C007." Typically, each carrier route is related to
where a particular mail carrier delivers.
There are approximately
600,000 unique carrier routes in the US.
Of these, approximately half are assigned to post-office boxes, leaving
approximately 300,000 that represent “boundaries” or delivery areas. These numbers fluctuate slightly from month
to month. Since there are approximately
40,000 valid ZIP Codes in the US that translates to an average of 15 carrier
routes per ZIP Code. Obviously any
particular ZIP Code could have many more or many fewer than this average.
Yes. The USPS makes minor changes to the delivery
routes continuously, usually due to either population or staff changes. For example, as new homes are built, those
new addresses must be added to a carrier’s delivery route. Budget changes at local post offices can also
impact delivery definitions because of staff or technology modifications. Most of these changes are minor – adding or
deleting a few streets or moving a few addresses from one carrier route to
another. However, sometimes an entire
delivery system for a county can be disrupted as entire ZIP Codes are added or
subdivided.
While the change can be
initiated by local post offices, the USPS headquarters in Memphis, TN is the
only entity to aggregate individual carrier route change information
nationally. They release a monthly database of all carrier route
definitions. There are many independent
companies that license various subsets of this database to help other
businesses ensure that large mailings are addressed efficiently for
delivery.
Somewhere in the US, a
carrier route changes every day. The
USPS releases a monthly database of the latest definitions, but it does not
“track” the changes per se. Some changes
are very subtle – one new address added because a new home was built at the end
of a street – and so tracking the type of change is an expensive effort few
commercial organizations have undertaken.
Nationwide, each month you
can expect at least 100,000 changes (adds, deletes, or modifications) to the
carrier route definitions. That
represents more than 15% each month!
Each carrier route is
explicitly defined as part of a single ZIP Code. The full 9 digits of the carrier route code
(e.g. 12508C007) is a unique code that represents each carrier route and so, by
definition, it cannot cross multiple ZIP Codes.
Although a ZIP+4 code also has 9 digits, it is not the same as a
carrier route code. There are far more
ZIP+4 codes in the US – approximately 40,000,000, usually assigned to one side
of a street block. Each carrier route
contains tens or hundreds of ZIP+4 codes. Additional info on ZIP+4 maps and lists can be found on the
web.
Carrier routes can be
sub-characterized as city, rural, PO Box, or highway contract routes - each
based on what kind of delivery mechanism is used. The letter at the start of
the carrier route number indicates the sub-characterization. The designation
"R" denotes a rural delivery carrier route where mail is delivered
via automobile. A "C" designation means that it is a city delivery
route, where mail is delivered on foot by a postal service employee. The
designation "B" indicates that is "PO box delivery". These
carrier routes cannot be mapped by mapping firms because multiple labels overlap
significantly. Regardless of the sub-characterization, all postal discounts
allowed for mailing by carrier route will apply. While these letter-based
designations can give you some idea of the density of occupants to expect in
any given carrier route, they do not limit your ability to send direct mail.
The USPS does not usually
define carrier routes by the type of occupant receiving mail: any given carrier
route could include any or all of the above types of recipients. However, it is
possible to get summary counts for any carrier route from your list provider or
mapping service bureau showing the number of deliverable addresses for
businesses, MFDUs (multi-family dwelling units), and SFDUs (single family dwelling units). You can use this data
to target your mailings to carrier routes heavy in the type of recipient of
interest to you.
Canada’s postal system is
designed a little differently than that in the US. Canada uses a 6-digit code, called the
“FSALDU”, where the FSA is similar to a US ZIP Code and the LDU is more akin to
a US ZIP+4.
A saturation mailing is
simply any mailing campaign that mails to at least 90% of the residential
addresses within a postal carrier route.
Many mailers erroneously think that a saturation mailing must be
conducted by ZIP Code but the actual definitions from the USPS for the maximum
saturation discount uses the carrier route as the defining region. Also check
out the great USPS Discount Mailing Services webpage at http://pe.usps.gov/text/dmm200/discount.htm
.
When you mail by saturating
a carrier route, you can expect to save between 50-60% on your mailing postage
costs. Similar savings can be obtained
by doing a “high density” mailing where you mail to at least 125 addresses in a
carrier route. For the most current
rates, you should work with your lettershop or list
provider, or call you local post office. For current postal rates, click here.
When you prepare your
mailing according to USPS guidelines, including meeting the saturation
criteria, it makes the post office’s job easier. It reduces the time-consuming
coding and sorting that is part of the USPS's mail
delivery process.
Any business attempting to
reach the majority of residents in a localized area should mail by carrier
route.
A resident occupant list is
a list of addresses of all residents in a particular area, prepared by a
commercial list provider. It comes
pre-sorted and saturated by carrier route and guarantees the maximum postal
discounts.
All major direct mail
campaigns should be running the address files through an address
standardization process known as "CASS," following strict USPS
guidelines. Even non-saturation mailings
should be CASS certified prior to mailing to ensure the maximum delivery. CASS checks the addresses against a USPS file
of deliverable addresses, corrects any typos in your address file, appends the
ZIP+4 and carrier route codes (along with some other codes not relevant to this
discussion). Your list provider should
always run the list against a CASS process before giving it to you, but your lettershop or other service bureau can CASS your existing
customer database for you. You can also use carrier routes to target new customers.
Because your file should
always be CASS certified (see previous question), you will always have both a ZIP+4 code and a carrier route code on your address
file. However, the maximum postal
discount only applies when mailing to at least 90% of the residential addresses
within a carrier route. There are comparatively minimal discounts for mailing
by ZIP+4. Hence “mailing by carrier
route” is usually most advisable.
For service bureaus that
analyze your files, it is also a lot easier to work with the smaller carrier
route database (~600,000 records) than the large ZIP+4 database (~40,000,000)
so data processing costs are generally much lower for files sorted by carrier
route.
Many demographic data
providers are able to generate statistics on income, age, and other
demographics based on carrier route.
A carrier route map simply
shows the geographic boundaries that delineate carrier routes. You can download a sample carrier
route map (opens in PDF format) here.
Through an extremely complex
process, the address data released by the USPS is matched to street map
databases. The resulting street segments
are then grouped together to form a “boundary”.
Sometimes these boundaries are discontinuous – a carrier route may be
represented by more than one polygon when a mail carrier delivers to
non-adjacent neighborhoods in a ZIP Code.
The process of generating these carrier route map polygons is surprisingly
NOT performed by the USPS. Private
companies generate these boundaries.
A carrier route centroid is simply the center point of the carrier route
boundary polygon.
If the company creating the
carrier route boundaries is using accurate data and a reliable process, carrier
routes should never cross a ZIP Code.
The best mapping providers update their carrier route data monthly, which
is as often as the USPS updates its official records, and have 100%
synchronization with their ZIP Code data.
Carrier route reports list
the carrier routes for each ZIP Code in a spreadsheet (click here for a
sample). These reports can also list
delivery counts or other demographics.
By mailing to entire carrier
routes rather than entire ZIP Codes, you can still qualify for the maximum
postal saturation discounts while you eliminate areas where you will not likely
get a response. By using a map, you can
actually see where those carrier routes are located relative to your market.
Because there are almost 100
times as many ZIP+4s than carrier routes, it is nearly impossible to map and
label all the ZIP+4s in an area larger than a few hundred feet. Plus, mailing by ZIP+4 offers minimal postage
discounts compared to carrier route saturations.
A resident occupant list is
a prepared list of addresses of all residents in a particular area. It comes pre-sorted and saturated by carrier route
and guarantees the maximum postal discounts.
With a corresponding map, you can locate those carrier routes on a map
and eliminate carrier routes you don’t want to mail to. The best use of the map comes before
purchasing an address file. By seeing those
carrier routes mapped out, you can only order the addresses you really
need. This saves money on lists,
printing, and postage.
List compilers and map data
compilers have different operating schedules and it is nearly impossible to
ensure 100% synchronization between the two, especially since the data sources
(USPS and commercial street map data) change every day. Occasionally, carrier route maps and resident
lists have minor discrepancies.
Many demographic data
providers are able to generate statistics on income, age, and other
demographics based on carrier route and these can be easily added to maps by
professional mapping service bureaus. However, getting accurate carrier route
demographics is not easy. See our page on carrier
route demographics for some guidelines to watch for.
The USPS does not provide
maps, instead they refer their business customers looking for carrier route or
ZIP Code maps to the Maponics
Online Store. You can look up the carrier route code for individual
addresses on USPS.com though. Click here for
some links to USPS.com website lookups.
There are many things to
check for when comparing mapping quality.
Maponics has developed a good set of considerations that you can view by
clicking here.
There are parts of the
country that do not have USPS mail delivery.
Database compilers, particularly mapping companies, generate ZIP Code maps
for the whole US such that there are no gaps between ZIP Codes. However, it would be misleading to do so for
carrier route areas. If a portion of a
map shows no carrier route boundaries, it likely means that there are
insufficient deliveries in the area, which is instead probably served through a
PO box.