An excellent article from New Geography about growth patterns, particularly appropriate to Sacramento and its current focus on building population in the downtown core.
An analysis of the just-released municipal population trends shows that core city growth is centered in the municipalities that have the largest percentage of their population living in suburban (or exurban) neighborhoods.
Improved Urban Core Analysis
There is considerable interest in urban core population trends, both because of recent increases in the interest of urban planning orthodoxy to restore living patterns more akin to the pre-World War II era. At that time, urban areas were considerably more densely populated, commuting travel was much more focused on downtowns (central business districts or CBDs) and automobile use accounted for far less of urban travel than today.
Most previous analysis has equated historical core municipality (core city) data with the urban core. The core cities are generally the original settlements, as they have evolved by expanding their city limits. Around these core cities, suburbs and exurbs have developed, which combined with the core cities make up the metropolitan area. Metropolitan areas are the “economic” dimension of contemporary cities.
However, even the most cursory analysis demonstrates that equating core cities with the urban core is far from ideal. Historical core municipalities vary greatly in their percent of their population living in traditional high density neighborhoods. For example, in core cities like New York, Boston and San Francisco, nearly all people live in neighborhoods that can be classified as urban core. In others of the largest core cities, virtually all of the population lives in neighborhoods that are suburban or exurban, in view of their low densities and overwhelming automobile orientation. These include examples like San Antonio, Phoenix and San Jose. Even core cities perceived to have a strong urban core, such as Portland and Miami, have considerably less than 50% of their population in urban core neighborhoods.
Overall, historical core municipalities have little more than 40% of their population living in urban core neighborhoods. When non-core principal cities or primary cities are equated with core cities, there is even less association with the urban core. Overall, non-core principal cities have less than 10% of their population living in urban core neighborhoods.
This has changed in recent years, with the introduction of the annual American Community Survey and its small area data, such as for ZIP Code analysis zones (ZCTAs). Even so, the comprehensive publication of small area data tends to lag approximately three years behind population estimates. Thus, the small area data that would make it possible to compare population trends to 2014 by functional urban sector within core cities will not be released until 2017.
This article classifies 2010 to 2014 core city population growth by the percentage of urban core population according to the 2010 census. The classification was developed using my City Sector Model, which classifies every zip code in metropolitan areas as pre-War urban core (CBD and inner ring) or post-War suburban or exurban (Figure 1). Simplified, the City Sector Model classifies as urban core any small area with an employment density of 20,000 per square mile or more or a population density of 7,500 per square mile or more, with a transit, cycling and walking work trip market share of 20% or more (Note).
Growth by Extent of Urban Core Population
More than 50% of the growth between 2010 and 2014 has been in core municipalities that are more than 90% post World War II suburban or exurban (0 to 10% urban core). This growth share is nearly one-half higher than their population share of 35%.
Retrieved June 9, 2015 from http://www.newgeography.com/content/004948-growth-concentrated-most-suburbanized-core-cities