Understanding ZIP Codes in Large Cities: History and Determination
ZIP codes are denoted as postal codes used in the United States to assist in sorting and delivering mail efficiently. In large cities, the assignment of ZIP codes is a multifaceted process that balances logistical efficiency with the needs of residents and businesses. Let's explore the key principles and factors that influence the creation and assignment of ZIP codes in large cities.
Key Principles and Factors for Determining ZIP Codes in Large Cities
Geographic Areas: ZIP codes are typically assigned to specific geographic areas. In larger metropolitan areas, these areas can correspond to neighborhoods, districts, or even smaller subdivisions. The United States Postal Service (USPS) aims to create ZIP codes that facilitate efficient mail delivery.
Population Density: Areas with higher population densities may have more ZIP codes to accommodate the volume of mail and ensure quicker delivery times. This is evident in urban neighborhoods, where multiple ZIP codes can be found within a single district.
Route Optimization: The USPS uses data on mail routes and delivery patterns to assign ZIP codes. This helps streamline the sorting and delivery process, making it more efficient for postal workers.
Historical Factors: Some ZIP codes have historical significance and have been in place for a long time. Changes in population, urban development, or postal routes can lead to the creation of new ZIP codes or modifications of existing ones.
Administrative Considerations: Local government boundaries, school districts, and other administrative divisions may influence ZIP code assignments. For example, a ZIP code may encompass an area that aligns with a city council district or a school district.
Special Designations: Certain large cities have specific ZIP codes for certain types of addresses, such as businesses, government buildings, or institutions (e.g., universities) which may have their own dedicated codes.
The History of ZIP Codes in Los Angeles
Before the implementation of ZIP codes, Los Angeles used a system of zones. In this system, the zone numbers were assigned alphabetically based on the name of the local post office.
Zone System: For example, my folks lived in LA35, which corresponded to Hollywood, which was LA28. The zone numbers were assigned alphabetically based on the name of the local post office.
Transition to ZIP Codes: When the ZIP Zone Improvement Program (ZIPZIP) codes were introduced, Los Angeles became a Sectional Center Facility (SCF) with the zip code 90035, while Hollywood was assigned the zip code 90028. This transition reflected the growing need for more efficient mail delivery.
Area Growth and ZIP Code Assignment: Over time, certain areas in Los Angeles would outgrow their ZIP code and would be assigned a new one. For instance, UCLA, which was originally part of 90024, grew to have its own 90095.
Broader Area ZIP Codes: The area south and west of UCLA was assigned new zip codes: 903 (Inglewood), 904 (Santa Monica), 905 (Torrance), and 902 (everything else, assigned alphabetically by city name starting with Bell).
SCF in LA: All four prefixes were handled by a single SCF near LAX (Los Angeles International Airport).
Conclusion
The assignment of ZIP codes in large cities like Los Angeles is a complex process that balances logistical efficiency with the practical needs of residents and businesses. Understanding these principles and historical factors can help provide insight into the evolution and ongoing use of ZIP codes in urban areas.