A primary purpose of resilient planning is to prepare communities for economic downturns such as recessions and reductions in base employment. Resilient communities tend to cluster the built environment to minimize travel and its costs. The foundation for such physical design is the use of street grids which help to relieve congestion resulting from more compact development. A concern is potential higher costs from increased street mileage. However, much of this can be offset by reductions in street widths in accordance with the Congress for New Urbanism Designing Walkable Urban Thoroughfares: A Context Sensitive Approach. Traditional Neighborhood Development (TND) complements street grids in residential areas. Single family homes in TNDs tend to be multi-story to reduce footprints on lots with widths of about 25’ to a maximum of about 60.’
TND typically has home frontages set back about 30’ or less from the nearest street curb. Conventional residential street widths tend to be at least 30’ from curb to curb to allow for two vehicles to pass easily with parking on one side. These street widths are often up to 35’ to 40’ or more to allow for parking on both sides. Such over-sized design is usually driven by the concern to ensure quick and unimpeded access by emergency vehicles. The reality is that, apart from arterials and collectors, these widths are rarely needed. Ideal and efficient residential street form allows for curb parking while ensuring traffic flow in at least one direction. This calms traffic and reduces the chances for accidents. When vehicles moving in opposite directions meet, one needs to wait behind a parked car for the other to pass. In a worst case scenario, a fire truck responding to an emergency and meeting a car from the opposite direction might require the car to back up and could delay the response briefly. Intuitively, this is acceptable as the odds of it occurring are not high enough to justify eternal costs related to maintenance of oversized streets and increased travel from related low density development.
Visual preference surveys tend to show that people prefer human-scale development that creates a sense of place while encouraging pedestrian activity and interaction between neighbors. See results like this from such a survey conducted for the Winnebago County, Illinois Land Resource Management Plan in 2006-2007. To create a sense of enclosure both on the street and within the neighborhood, a general rule of thumb is that the distance between home frontages across the street from each other should be no more than about three times the typical building height. Consequently, frontages of two-story homes about 30’ in height on a 20’ wide street should not be set back from the nearest curb by more than 35.’
The diagram below depicts three scenarios for neighborhood design to accommodate 48 houses. Each of the figures is presented in a rectangular format for ease of comparison. The diagrams are primarily to demonstrate differences in the amount of land needed and the level of impervious surface. Figure B represents conventional layouts of residential subdivisions that became more prevalent in the post-World War II period. Homes in this scenario tend to be single-story with expansive footprints on large lots fronted by three-car garages along wide streets. As a result, the 48-lot development uses about 28.5 acres of land. About one-third of this or 9.3 acres is impervious surface.
Figure A shows an example of TND with street widths about 25% less than in Figure B and the addition of alleys. The TND depicts more moderately sized two-story houses with less than one-third the footprint of conventional homes. Lot sizes and widths are much less than one-half of the conventional design. Further, Figure A uses only about 10.4 acres of land or almost one-third less than the conventional development. The proportion of impervious surface goes up slightly with the TND design but the total is reduced from 9.3 acres to 3.9 acres. Included is a reduction of about one-third in the use of pavement or other surfacing for vehicles. This is despite the use of alleys which often give the impression of an excessive extravagance requiring more public upkeep. Essentially, alleys are common driveways that virtually eliminate the needs for private vehicle entrances.
Figure C is an alternate TND that is more moderate in the differences with the conventional design. It eliminates alleys while using a mix of front and rear-loaded garages. Consequently, the TND advantages in terms of land use and impervious surface are not quite as dramatic as the design with alleys. However, the design in Figure C may be more tolerable by community stakeholders that often will insist upon the availability of homes with attached garages.
Bitter analyzed almost 75,000 single-family housing transactions in the Tucson, Arizona area in an attempt to quantify the effect of subdivision “vintage” on the prices of homes in those areas. The data was compared with county assessment information to identify independent variables that influence housing values. Findings indicate a definite association between sale prices of homes and the decade in which the subdivisions were recorded. Newer homes generally command higher prices, however, the difference narrows substantially when measured in terms of per square feet. Further, on a per square foot basis, homes built in the periods before 1920, the1920’s, and the 1930’s realized respective sales prices that were 27, 7.5, and 11 percent higher than Tucson’s newest housing developments. Conversely, homes built in the 1950’s and 1960’s sold for about 12 percent less than those in modern subdivisions. Home appreciation rates were also found to be highest with the pre-1920’s homes, strong with those constructed in the 1920’s to 1940’s, while post-1990 housing developments increased at the slowest rates. The study concluded that controlling for all other variables, homes in developments recorded before 1940 realized statistically significant price premiums of 5-7 percent compared to those subdivisions platted after 1990. On the contrary, homes built in the 1950’s and 1960’s realized discounts of about 2-3 percent compared to development in the post 1990 period. Home construction during the 1940’s was not statistically different from zero. This period can be considered a time of transition between traditional and auto-oriented development. Thus, there seems to be excessive demand for the older vintage homes that is not being met by supply. It appears there may be at least a market niche for homes with classic design features to be built in those older developments that have other complementary characteristics.[i]
A comparable study of sales prices in the city of Chicago during the 1983-2003 period covering homes built from 1890-2003 or 262,142 transactions found that homes built between 1900 and 1940 command a significant premium which lessens in the latter two decades. The findings suggest that these older homes are valued for their craftsmanship and design.[ii] Song and Knapp studied various neighborhoods via 48,000 sales transactions in Washington County, Oregon (western portion of Portland metropolitan area) by focusing on six characteristics that influence housing values: physical attributes of the homes; public service levels; amenities/ disamenities; socioeconomic characteristics; location; and New Urbanist design features. Data sources were 48,070 sales transactions from 1990-2000, property assessments, and the U.S. Census. They found that New Urbanist developments command price premiums of 15.5 percent due to a number of features such as evenly distributed mixed land uses, walkable distances to commercial districts, smaller block sizes, availability of light rail nearby, and gridded street networks. Characteristics that reduced the value of these homes consisted of close proximity to major arterials, and dense developments with high proportions of multifamily, public and commercial uses.[iii] Hachey and Grubaugh studied home sales and features data covering 520 transactions during the period of 1983 to 1985 for the town of Newbury, Massachusetts. The authors found that architectural quality in the form of Federal, Victorian, and Colonial styles command premium prices of about 20 percent while Garrison-styled homes were about 14 percent. Of note is that this also applied to newer homes with features that replicated those of these vintage housing styles. The existence of historic districts did not have any impact.[iv]
[i] Bitter, C. (2013). Subdivision Vintage and Housing Prices: Do Home Buyers Value Traditional Development? Urban Studies, 51:5, 1038-1056. Viewed on August 14, 2016 via http://usj.sagepub.com.ezproxy.snhu.edu/content/51/5/1038.full.pdf+html?.
[ii] Coulson, NE, McMillen, DP. (2008). Estimating Time, Age and Vintage Effects in Housing Prices. Journal of Housing Economics, 17, 138-151. Viewed on August 14, 2016 via http://ac.els-cdn.com.ezproxy.snhu.edu/S1051137708000107/1-s2.0-S1051137708000107-main.pdf?_tid=49215f50-621e-11e6-8f56-00000aab0f26&acdnat=1471179469_061136fe9cae2eea0bc175e0b537e893.
[iii] Song, Y, Knaap, GJ. (2003). New Urbanism and Housing Values: A Disaggregate Assessment. Journal of Urban Economics, 54:2, 218-238. Viewed on August 14, 2016 via http://ac.els-cdn.com.ezproxy.snhu.edu/S0094119003000597/1-s2.0-S0094119003000597-main.pdf?_tid=eed8b3ee-889d-11e6-a7f9-00000aacb360&acdnat=1475412438_d7ba7eaec729e6cd0dca9512be2e2cea.
[iv] Hachey, G, Grubaugh, S. (1989). Architecture, Historic Zoning, and the Value of Homes. Journal of Real Estate Finance Economics, 2: 181-195. Viewed on August 14, 2016 via http://eds.b.ebscohost.com.ezproxy.snhu.edu/eds/pdfviewer/pdfviewer?vid=7&sid=a6660943-8ca1-4d5a-be71-0fe35f3bbd63%40sessionmgr105&hid=104.