Density's Next Frontier: The Suburbs

[M II A II R II K]

America’s New Metropolitan Landscape: Pockets Of Dense Construction In A Dormant Suburban Interior


FEB 1, 2018

By Issi Romem

Read More: https://www.buildzoom.com/blog/pocke...urban-interior

.....

The high cost of housing in America’s expensive coastal cities can be addressed by densifying the suburban landscape. At first glance this may seem obvious; combatting price appreciation calls for building more homes, and better to do so through infill than by exacerbating sprawl. But the notion of densifying the suburban landscape is a more radical departure from the status quo than it may seem.

- In the past, virtually every patch of land in the metropolitan U.S. continually sprouted new housing, but this is no longer the case. In recent decades, residential construction has become increasingly confined to the periphery of American metro areas, while a growing swath of the interior has fallen dormant and produces new homes at a negligible pace. At the same time, a tiny fraction of the land area, scattered in small pockets throughout the metropolitan landscape, is responsible for a growing share of new home production, primarily in large multifamily structures. I refer to this increasingly spiky new pattern of housing production as “pockets of dense construction in a dormant suburban interior.”

- Most of the metropolitan land area in the U.S. consists of low-density suburban fabric whose housing density is effectively capped by local land use policy. When such fabric is young it can usually accommodate more housing through infill, first with entire new subdivisions filling in gaps in sprawl, and later with development of smaller vacant lots. Such infill comes at the cost of open space, but it tends to fall in line with the rules maintaining the low-density character of the area. As long as accommodating more homes relies on devoting more land to housing rather than using previously developed residential land more intensively, it can occur within the framework of current density-prohibiting land use policy without drawing fire.

- Thus, without allowing previously developed residential land to be redeveloped more densely, the capacity of suburban areas to accommodate more housing is bounded by their ability to devote additional lots to housing. Once suburban fabric matures, in the sense that the land cover is saturated with development, then the production of new homes usually grinds to a halt. Pockets of dense construction are the exception – places in which dense housing projects are not unthinkable. --- In general, more local control over development is detrimental to densification. The opponents of development tend to be concentrated locally, while those who stand to benefit from it tend to be widely dispersed and unaware.

.....

In the 1940s and ‘50s the map was mostly light blue, indicating that the vast majority of the metro area’s developed footprint was producing new housing at a meaningful pace, mostly but not exclusively in the form of single-family homes.






By the 1960s and ‘70s, light blue areas still accounted for most of the developed footprint, but they were losing ground. A growing area saw new housing dominated by 2 to 49 unit structures, and the number of red Census tracts in which large multifamily structures accounted for most new homes increased as well.






The pattern of pockets of dense construction in a dormant suburban interior began to emerge more clearly by the 1980s and ‘90s. Much more of the metropolitan landscape was dormant by this period, showing up in dark blue, while clusters of dense new home construction appearing in red had multiplied.






Since the turn of the century, the pattern of pockets of dense construction in a dormant suburban interior has become plain to see. The map consists primarily of dormant, dark blue areas producing new homes at a negligible pace, interrupted by red clusters of dense new residential construction.






The following pair of charts quantifies the progression over the decades illustrated in the maps.






The pattern that has emerged in the Los Angeles metro area is not unique; it is characteristic of metro areas nationwide. The diagram on the left below stylizes the pattern observed in the Los Angeles metro area, while retaining the geographic boundaries imposed by the ocean and the mountains and which channel the bulk of metropolitan expansion to the east.






Chicago Timelapse

[eschaton]

Seems to me the story of the LA data is more the decline of "missing middle" style housing.

In general, larger projects are much more cost-effective than smaller projects. As zoning codes have become more restrictive, the process has gotten worse. A big developer has the deep pockets needed to "grease the wheel" to get a project passed with variances. The same is not true for someone who wants to build a six-story apartment building in a predominantly SFH-dominated neighborhood.

As an aside, how are townhouses coded in this data?

[mhays]

Small buildings have inherent inefficiencies. I don't know about LA, but it's generally about basic economics.