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City of Change – Occupancy Density in Detroit’s Residential Neighborhoods

City of Change is a Data Driven Detroit (D3) blog series analyzing changes in Detroit’s residential neighborhoods from 2009 through 2014. This series is a collaborative effort between Noah Urban at D3 and Gary Sands, professor emeritus of urban planning at Wayne State University. 

**Note:  This blog post will make several references to Detroit’s Master Plan Neighborhoods. If you would like to view a reference map of these neighborhoods to help orient yourself, please click here.

Overview

This edition of City of Change analyzes the density of occupied residential structures (the number of residential structures per square mile that are occupied) and uses this indicator as a proxy for population.  Many neighborhoods in Detroit have endured increasing emptiness since 1960, though some areas of considerable density do remain. If these neighborhoods suffer decline, the potential impact on the city in terms of lost population and revenue is far greater than decline in areas of lower density.

As in the previous installment of City of Change, the data have been summarized for 840 census block groups in the city of Detroit. To account for differences in the size of the block groups, the analysis measures the number of occupied residential structures per square mile. The occupancy rates are based on data collected by the Detroit Residential Parcel Survey (DRPS) in 2009 and Motor City Mapping in 2014.

Occupancy in 2009

Detroit had an average of just over 2,100 occupied residential structures per square mile in 2009. This figure represents a substantial decline (almost 43 percent) from a peak of 3,675 structures per square mile in 1960 (based on archival Census data). The declines over that half-century have been severe across the city — just 18 block groups in 2009, out of 840 total, had occupancy densities greater than the 1960 citywide average.

There was considerable variation evident across block groups, with densities ranging from 51 to more than 4,500 occupied residential structures per square mile. It is important to note that some block groups with low residential densities contain large parcels with industrial, institutional or commercial land uses (parks, cemeteries, factories, etc.). In these areas, residential density is below average, regardless of the vacancy rate. In block groups that are predominantly residential, however, a low occupancy rate can reflect both a predominance of vacant lots and a high number of vacant residential structures.

The highest occupancy densities were generally found on the Far East Side (particularly in the Finney and Denby neighborhoods), the Northwest Side, and in neighborhoods close to Dearborn (particularly the Cody Rouge area). The relatively high density in these latter block groups was likely affected by the expansion of the growing immigrant population in Dearborn. Although many of the areas closest to downtown were not included in the DRPS project boundaries, areas closest to the city center possessed some of the lowest densities. Even along the east riverfront, occupancy levels were primarily in the bottom two ranges.

Figure 1:

MCI_DRPS_OccupiedStructures

This map shows the density of occupied residential structures per square mile in Detroit based on data from the 2009 Detroit Residential Parcel Survey. Note that the Detroit Residential Parcel Survey only collected information for 1-4 unit residential structures.

Occupancy in 2014

Continued population decline over the past five years, along with increased demolition activity, brought the average density of occupied residential structures down to 1,860 in 2014, almost 12 percent below the 2009 figure and less than half the peak density of 1960. As indicated in Table 1, the number of block groups in the highest-density range decreased by 77, or more than 35 percent. The lowest-density block group had just 18 occupied residential structures per square mile.

Table 1: Change in Density of Occupied Structures

 Number of Block Groups
Occupied Structures per Square Mile20092014Change
2,850 or Higher210133-77
2,166 to 2,849210197-13
1,411 to 2,165210216+6
1,410 or Lower210294+84

The decline in occupancy occurred across the city. While the same general areas continued to have the highest occupancy densities, many of the block groups shifted from the highest to the second-highest category, indicating that even denser neighborhoods are experiencing depopulation. Declines are particularly noticeable on the East Side, including much of the Osborn area (identified as a portion of the Mt. Olivet Master Planning neighborhood). Densities remained high in areas with large immigrant populations, including the area just north of Hamtramck. There are even fewer block groups than in 2009 that are close to the city center and have residential occupancy densities higher than the lowest range.

Figure 2:

MCI_MCM_OccupiedStructures

This map shows occupied structures per square mile in 2014, using the same ranges as the map from 2009. Note the considerable decrease in the number of block groups in top range. This decrease is even more notable when considering that the Motor City Mapping survey expanded upon the DRPS to encompass all residential structures.

Absolute Changes in Residential Density Between 2009 and 2014

Between 2009 and 2014, only 90 block groups recorded an increase in residential structures per square mile; 10 recorded no change, and 740 recorded a decline. Thirteen percent of all block groups reported declines of more than 600 units per square mile in only five years. Areas with increasing occupancy densities are found along the Woodward Corridor and the Near West Side (Woodbridge and Corktown areas), which have been the focal points of several residential investment initiatives. Elsewhere in the city, some of the higher-density block groups in 2009 did observe an increase in residential occupancy density, but these areas are somewhat randomly distributed.

Figure 3:

MCI_OS_Change

This map shows block groups that saw either an increase or a decrease/no change in occupied structures per square mile from 2009 to 2014. The block groups in the latter category accounted for nearly 90% of all block groups studied in this analysis.

To a large extent, the decline in occupancy density is a result of a rise in vacancies, rather than a decline in the number of residential structures. In 2009, the average residential occupancy density was 82 percent of its maximum potential (that is, if every residential structure in the block group were occupied). In 2014, the average was just 73 percent of the maximum potential. The number of block groups where the occupancy density was less than half of the potential increased from just five in 2009 to 44 in 2014.

Conclusions

The past five-year period has seen a substantial decrease in the density of occupied residential structures in Detroit. Since the number of new homes built during this period was relatively low, the lower densities are the result of higher vacancy rates in the existing housing stock. A net increase in the number of households occurred in just 10.6 percent of the block groups. These trends seem to suggest that, aside from scattered pockets throughout the city, the population declines that have characterized the past fifty years in Detroit – culminating in the 25 percent decline in population from 2000 to 2010 – are continuing. Future policies should recognize this trend and, in addition to aiming to reverse the decline, should address the potential that it may continue in the future.

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City of Change will return in two weeks with an in-depth examination of mortgage deeds and residential market health in Detroit’s neighborhoods over the past five years.

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The Motor City Mapping data referenced in this article are available in their raw format on the Data Driven Detroit (D3) Open Data Portal – http://portal.datadrivendetroit.org.

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