The following maps show the evolution of this process across greater Los Angeles over the past half century or so. On the maps, light blue represents areas where new single-family construction predominated; orange indicates areas of medium-density developments, of two to 48 units; red shows areas of large multi-family construction, of 50 units or more; and dark blue indicates virtually no construction at all.

The first map shows L.A.’s development at the dawn of the postwar crabgrass frontier, 1940 to 1960. The great majority of the map is filled with light blue, indicating single-family-home construction, with orange areas of small to midsized multifamily construction in and around the urban core.

Development in Los Angeles, 1940–1960

There is a still a great deal of light blue on the second map, which covers the years 1960 to 1980, and shows these same crabgrass suburbs but stretching out farther into the periphery. There are small specks of red near the urban center, and somewhat larger areas of orange stretching out from the core.

Development in Los Angeles, 1960–1980

Buildzoom

But in the 21st century, the pattern changes dramatically. Now the great bulk of the map is dark blue—vast swaths of no construction. More than half of L.A.’s built-up areas have hosted no new housing construction this decade. While most urban theorists complain about land-use restrictions in the urban core, and urban NIMBYs, there are considerable areas of red and orange in downtown L.A., Hollywood, and large parts of the Westside and the San Fernando Valley. The areas with no new housing tend to envelop large swaths of older, closer-in suburbs. From this map, restrictive land-use policies and NIMBYism appear to be more a problem of the old crabgrass suburbs than of the inner city.

Development in Los Angeles, 2000–2016

Buildzoom

While L.A. provides a particularly useful illustration of America’s dormant suburbs, it is far from unique. Romem’s study shows how this pattern fits virtually all U.S. metropolitan areas. Over time, a larger and larger share of their land is taken up by dormant single-family neighborhoods that are failing to add any new housing.

Still, there are important differences between metro areas, according to the study. Large Sunbelt cities, such as Atlanta, Dallas, and Phoenix, have demonstrated a much greater capacity to expand outward at a low density, while their cores gradually get denser. Lagging Rust Belt cities like Cleveland and Buffalo have seen much less growth out across their suburban periphery, and modest or minimal increases in density in their urban cores as well. Many expensive coastal urban areas, with the Bay Area being the prime example, have slowed their outward expansion due to policies meant to curb sprawl. Nonetheless, all these different types of cities have large areas made up of dormant suburbs with little or no new construction.