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Centralized Mail Delivery: A History

When most people think of mailboxes, they think of the standard curbside model that’s popular for most homes and many businesses, especially smaller businesses. Most mailboxes are of this type, and they have their own history, but centralized mail delivery also plays an important role in mail delivery.

Centralized mail delivery is any type of mailbox system that contains more than one mailbox in the same place and is meant to serve multiple residential or commercial customers. While multi-unit curbside mailboxes could count as a form of centralized delivery, this blog looks at the history of other types of centralized mailboxes. These commercial mailboxes, in their modern form, have multiple customer compartments contained in the same cabinet.

Centralized mailboxes are preferred by the USPS for most communities and commercial properties, as they make mail delivery easier, protect mail, and resist the type of damage that often occurs with curbside mailboxes.

Before Centralized Mail Delivery

Before 1923, postal carriers for the USPS often had to deliver mail to each household and business by hand, which would often add hours to the workday. For this reason, mailboxes or mail slots became required for each household in that year, with the goal of improving efficiency and cutting costs.

Of course, this change meant that mail was often left unguarded in mailboxes, which could be mounted at a curb without regulations.

As the US population grew and more businesses needed mail delivery, it became clear that mail delivery needed to become even more efficient and fast. As the USPS relied increasingly on vehicles such as trucks to carry mail, package volume and mail increased. The USPS determined that centralized mail delivery would not only make mail delivery easier but would also help to cut on labor costs. This growing need would give rise to centralized mail delivery and the mailboxes that would accommodate it.

The Beginning of Cluster Mailboxes

In 1967, the USPS launched a new experimental program to test centralized mail delivery. The USPS installed the first cluster mailboxes in some areas and took responsibility for maintaining them.

These mailboxes were often referred to as cluster mailboxes or neighborhood delivery and collection box units (NDCBU’s.) These mailboxes stood on pedestals outdoors and consisted of a metal cabinet that contained two or more customer units each. These mailboxes were made of aluminum and were typically rear loading with locked customer compartments.

This program ran until 1976, when Congress raised concerns about these new boxes negatively affecting mail delivery service. As a result, the USPS temporarily stopped installing these mailboxes that year, and switched to encouraging customers to purchase and use centralized mailboxes for their communities and commercial properties.

However, not many customers adopted these new mailboxes, and by 1981, fewer than one percent of mail deliveries went to centralized units. Around that same time, the USPS became authorized to install and help maintain these units once again.

By 1985, the use of centralized mailboxes had increased, mainly in townhouses and smaller apartment complexes. Within the next couple of years, the USPS determined that these cluster mailboxes helped to save money on each delivery for homes and townhouses, and thus the encouragement of these mailboxes increased over the years.

Evolving Centralized Mail Delivery

As cluster mailboxes became more and more common due the benefits for both customers and the USPS, so did mail volume, packages, and the need to keep mail more secure.

By the early 2000’s, package delivery increased due to the growing popularity of online shopping, and first-class mail delivery peaked. This increasing pressure on the USPS, along with the issue of package theft, spurred innovation in centralized mail delivery.

New cluster box units (CBU’s) became more popular, and in 2005, the USPS adopted new specs for these units, known as the STD-4C regulation. CBU’s were now to contain outgoing mail slots for customers, along with at least one parcel locker per ten customer units for holding packages. Manufacturers also needed approval and licensure to build and sell these units.

These new regulations also affected the size of each customer compartment and how far these compartments and parcel lockers could be from the ground or floor surface. They also provided for a master arrow lock for USPS access, and improved construction and customer locks.

These new regulations were required for all new construction after 2006, and the older mailbox types were now only approved for replacement of the same mailbox type.

One major benefit for customers was the versatility of these mailboxes, with some models able to recess into walls and others able to mount to vertical surfaces. Mailboxes could now come as front-loading or rear-loading models.

All mailboxes which meet these newest USPS regulations will be labeled as “USPS-Approved.”

The USPS also approved decorative toppers and pedestals for these centralized units, to help encourage property owners and community managers to use these units without worry of decreasing curb appeal and value.

Accommodating Packages

Over the next several years, as package delivery increased, parcel lockers became more available and needed in commercial properties as well as in communities who use centralized mail delivery.

Parcel lockers now come with almost all centralized mailboxes, but individual units for outdoor use have become more popular in areas that receive a lot of packages. These lockers could mount beside existing setups, increasing the ability to receive packages.

Most recently (as of 2021) all new apartment complexes must install at least one parcel locker per every five customer compartments, to meet this growing need. This is also required when installing new mailboxes or remodeling.

If You Have Questions

Centralized mail delivery was adopted due to its benefits to customers and the USPS. If you are seeking centralized delivery to new construction or looking to add to an existing setup, we’re here to help. Be sure to contact us today with any questions you may have.