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C Analysis of Density Assumptions and Feasibility of Committee Scenarios
Pages 211-231

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From page 211... ... The plausibility of the scenarios is tested by simply calculating how much change would be required from the trends to achieve the projected level of compact development by 2050 and then asking whether such change appears achievable. Conducting this analysis requires first a review of data sources and density measures. Read the entire page →
From page 212... ... The NRI data also include urban and built-up land beyond census-defined "urbanized areas" where a very large share of recent development has 1 Net residential acres include only residential land. Nonresidential land uses are excluded, as are local streets and parks (Downs 2004) Read the entire page →
From page 213... ... Rural transportation land consists of all highways, roads, railroads, and associated rights-of-way outside urban and built-up areas, including private roads to farmsteads or ranch headquarters, logging roads, and other private roads, except field lanes. In 1997, this category accounted for the remaining 22 percent of total developed land. Read the entire page →
From page 214... ... .3,4 By doing so, it is possible to estimate the amount of housing in each metropolitan and micropolitan area that is built at what are presumably the lowest density levels, as 3 Data on housing, measured at the census tract level, are drawn from the National Neighborhood Change Database, a special tabulation of data from the 1970 through 2000 censuses that allocates population and housing to the boundaries of the 2000 census. The 2000 census Geocorr application from the University of Missouri was used to collect data on the land area of all U.S. Read the entire page →
From page 215... ... For this reason the census data are referred to as gross acres in this appendix. Because of these pros and cons, both data sources are used here to examine density levels in light of recent development trends and how much change from current trends the committee's scenarios imply. Read the entire page →
From page 216... ... The population-weighted density measure provides a better sense of the density to which the average metropolitan resident is exposed rather than the density to which the average acre in the metropolitan area is developed. The former is more likely to reflect the local circumstances in which the typical person lives. Read the entire page →
From page 217... ... Density of average DU: 1990 3.02 DUs/acre Density of average DU: 2000 2.89 DUs/acre Density of average new DU developed: 1900–2000 1.93 DUs/acre New development as a share of 2000 average 67 percent as dense as the average Note: See Tables C-2 and C-3 for details. TABLE C-2 Change in Dwelling Units by Urban Acre, 1987–1997, Based on NRI Urban Acresa Year Number of Dwelling Units (DUs) Read the entire page →
From page 218... ... Average Percent Total Acresa Change Range -- Average Number Persons/ of Total 1990–2000 DU/gross DU/gross Persons/ square Change: acre acre acre mile 1990 2000 1990–2000 1990 2000 Percentage <1 0.6 1.50 960 62,779,845 72,862,155 10,082,310 75.5 75.7 76.5 1–1.9 1.4 3.50 2,240 10,050,874 11,914,815 1,863,941 12.1 12.4 14.1 2–2.9 2.4 6.00 3,840 4,713,174 5,494,329 781,155 5.7 5.7 5.9 3–3.9 3.5 8.75 5,600 2,460,770 2,739,475 278,705 3.0 2.8 2.1 4–7.9 5.5 13.75 8,800 2,296,743 2,443,374 146,631 2.8 2.5 1.1 12.0 30.00 19,200 798,832 832,758 33,926 1.0 0.9 0.3 8+ Total 83,100,239 96,286,906 13,186,668 100.0 100.0 100.0 Density of average acre, new and existing development, 2000 DU/gross acre: 1.11b Persons/square mile: 1,776c Density of average new acre developed: 1990–2000 DU/gross acre: 0.96b Persons/square mile: 1,536c Density of average new acre developed as a share of new and existing development in 2000: 86 percent Read the entire page →
From page 219... ... by the aggregate density of that category. For example, in 2000, the average number of dwelling units <1 DU/acre was 43,717,293, and the aggregate density for that category was 0.6. Read the entire page →
From page 220... ... development trends The trends in density are similar regardless of which data source or method of calculating density one uses. Over the decade of the 1990s, average densities declined because the average density of new development was lower than the average density of the existing development.6 On the basis of the NRI data, the density of the average acre (Method A) Read the entire page →
From page 221... ... declined slightly less sharply because only 47.5 percent of the new DUs developed during this period were built in census tracts with below 1 DU per gross acre and another 20 percent in tracts with between 1 and 2 DUs per gross acre. Less than one-third (31.9 percent) Read the entire page →
From page 222... ... Calculations Using NRI Data On the basis of the data from the NRI, which pick up lower densities at the urban fringe and leapfrogged development, if all new and replacement housing were to be built at the current average density of new development (the base case scenario) -- 0.99 DUs per urban acre -- the average density of the housing stock would fall from 1.66 DUs per urban acre in 2000 to 1.29 to 1.39 DUs per urban acre by 2050 (see Table C-4) Read the entire page →
From page 223... ... TABLE C-4 Changes in Density to Meet Targets of Committee Scenarios by 2050 NRI Data Census Data (Method B Only) a Density Percent Density Percent Level Change Level Change Number of Units (DU/urban from Number of Units (DU/gross from (millions) Read the entire page →
From page 224... ... . b Assumes the same range of housing units projected in Chapter 4, Table 4-3. Read the entire page →
From page 225... ... 10 than existing development, so average density increases from 2.9 DUs per gross acre in 2000 to between 3.07 and 3.13 DUs per gross acre, a 23 to 33 percent increase from the 2050 baseline. As with the NRI data, the census data show that doubling density in 25 percent of new development is equivalent to assuming that the average new development is slightly less dense than the average existing development. Read the entire page →
From page 226... ... For example, one way would be to eliminate half of all new development in tracts in the lowest density category (less than 1 DU per gross acre) , substantially reducing development in many urban fringe areas where lots are very large (see Strategy B in Table C-5) Read the entire page →
From page 227... ... Change in DUs Percent of Total Change in Acres Percent of Total <1 0 0 0 0 1–1.9 4,975,047 39 3,553,605 60 2–2.9 3,574,257 28 1,489,274 25 3–3.9 1,859,731 15 531,352 9 4–7.9 1,537,532 12 279,551 5 8+ 776,154 6 64,679 1 Total 12,722,721 100 5,918,461 100 Persons/Acrea Persons/Square Mileb DUs/Acre Density of average acre (Method A) Baseline 0.96 2.40 1,536 Strategy A 2.15 5.37 3,440 Percent change 129 129 129 25 percent higher density target 1.2 3.0 1,920 75 percent higher density target 1.68 4.2 2,688 Density of average DU (Method B) Read the entire page →
From page 228... ... Change in DUs Percent of Total Change in Acres Percent of Total <1 3,024,693 24 5,042,155 53 1–1.9 3,792,282 30 2,708,773 28 2–2.9 2,724,515 21 1,135,215 12 3–3.9 1,417,599 11 405,028 4 4–7.9 1,172,000 9 213,091 2 8+ 591,631 5 49,303 1 Total 12,722,721 100 9,552,564 100 Persons/Acrea Persons/Square Mileb DUs/Acre Density of average acre (Method A) Baseline 0.96 2.40 1,536 Strategy B 1.33 3.33 2,128 Percent change 38 38 38 25 percent higher density target 1.2 3.0 1,920 75 percent higher density target 1.68 4.2 2,688 Density of average DU (Method B) Read the entire page →
From page 229... ... Baseline 1.93 4.82 3,085 Strategy C 2.28 5.70 3,648 Percent change 18 18 18 25 percent higher density target 2.41 6.02 3,856 75 percent higher density target 3.38 8.43 5,399 Strategy D: Double DUs in Tracts Averaging >3 DUs/Acre, Redistribute Proportionately DUs/Acre (range) Change in DUs Percent of Total Change in Acres Percent of Total <1 4,792,239 38 7,987,065 73 1–1.9 2,067,223 16 1,476,588 13 2–2.9 1,485,169 12 618,820 6 3–3.9 1,950,936 15 557,410 5 4–7.9 1,612,936 13 293,261 3 8+ 814,218 6 67,852 1 Total 12,722,721 100 11, 000,996 100 Persons/Acrea Persons/Square Mileb DUs/Acre Density of average acre (Method A) Read the entire page →
From page 230... ... Given the large amount of land available for development and lax land use policies in more rural counties, achieving such a goal would require extraordinary changes in land use policy and market trends. The analyses provided here suggest that both the 25 and the 75 percent targets represent a significant departure from recent trends, which have involved lower densities than the average for new development over the decade of the 1990s and for decades before that. Read the entire page →
From page 231... ... references Abbreviations NRCS Natural Resources Conservation Service OMB Office of Management and Budget Downs, A Read the entire page →

From page 211...

... The plausibility of the scenarios is tested by simply calculating how much change would be required from the trends to achieve the projected level of compact development by 2050 and then asking whether such change appears achievable. Conducting this analysis requires first a review of data sources and density measures.

C Analysis of Density Assumptions and Feasibility of Committee Scenarios Pages 211-231

C Analysis of Density Assumptions and Feasibility of Committee Scenarios
Pages 211-231