| A code assigned to a group of addresses within a zip code that aids in mail delivery. Postal carrier route codes are often used with saturation mailings.In the U.S., 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. 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". |