There’s a science to it
Posted for Jenny Matlock’s Alphabe-Thursday study of the letter “Z.” I was a consistent poster for most of Round 5, but ran out of steam before we finished the series. Because I hate to leave anything undone, I am returning to the end of Round 6 to complete the entries I missed.
In 1963 the U.S. Postal Service introduced ZIP codes to the American public. Until then, the last line of a postal address was city, state except in larger cities where a two-digit code inserted after the city name (as in city ##, state) designated a zone within the city.
ZIP (Zone Improvement Plan) codes are crafted as follows:
- The first digit designates a geographic region of the United States (e.g., 0 for the New England states, the Virgin Islands, and military addresses in Europe; 5 for the upper Midwest states of Iowa, Minnesota, Montana, North and South Dakota, and Wisconsin).
- The second and third digits designate the sectional center facility (SCF) that services the post offices within that section. SCFs receive mail according to the first three digits of the zip codes and then sort the mail for all the post offices in their assigned areas.
- The last two digits represent an area of the city or a village or town outside the city. Interestingly enough, the last two digits for larger cities incorporated their former zone designations.
Beginning in 1963, the USPS conducted a comprehensive advertising campaign to promote universal adoption of the new addressing method. Mr. ZIP, the friendly cartoon postman pictured above, appeared on all manner of advertising (stamp books, postmarks, mailboxes, postal vehicles, etc.) to familiarize the public with the system and to promote its use.
In 1983, the USPS expanded the ZIP code system to ZIP+4 which was meant to assign a separate code to each and every mailbox. However, the add-on system was not widely accepted, probably because each +4 code had to be looked up separately and because the USPS continued to deliver mail even if it didn’t include the +4 extension. These days, the postal service relies on multi-line scanners that read the address, determine the correct +4 extension, and then spray on a bar code that includes all the information necessary to deliver the mail.