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by Dr. John Holtzclaw
Do studies of urban growth confirm the contention that compact areas help preserve the
environment and conserve energy? Let's consider three studies.
The first study looks at the educated, innovative and energy-wise residents of the
university community of Davis, California, near Sacramento. In the l970s they rewrote
their building code into an energy-conserving model for low density developments,
primarily single family. Stringent energy conservation and use of solar efficient designs
are mandated.
Yet, when Michael Phillips and Robert Gnaizda compared a recently constructed middle
class single family tract in Davis with a middle class apartment house near downtown San
Francisco, they got the results in Table l. The single-family home dwellers drove nearly 4
times as much! And transportation consumes nearly 2/3 of the nation's oil. The run of the
mill urban apartments use less than 1/5 as much heating fuel as the energy-efficient Davis
single-family houses. Sharing walls shares and saves heat. Exposing less wall and roof
area to the sun reduces summer air conditioning loads. Residential and commercial heating,
cooling, lighting and motors consume 20 percent of our country's oil. And the
single-family houses consumed 40 times as much arable land--translated, that usually means
the farmlands, ridgelands and wetlands we are working so hard to preserve. And they
required 5 times as much utility pipes.
The second study is an extensive analysis of two models of suburban growth. In their
1974 study for the Council of Environmental Quality (CEQ) and Housing and Urban
Development (HUD), "The Costs of Sprawl," the Real Estate Research Corporation
compared typical suburban single-family housing with suburban "high rise
apartments."
However, at 33 units/acre, these "high rise apartments" are actually less
dense than many older, comfortable urban neighborhoods. Densities of 50 to 100 units/acre
are common with 3 to 6 story apartments, and to 400 with occasional highrises and no
front-yard setbacks. Examples are the popular Nob Hill and Russian Hill areas of San
Francisco traversed by cable cars climbing halfway to the stars. Since the study is of
suburban "high rise apartments" with little transit, much land set is aside for
parking lots, driveways and lawns.
Even these modest "high rise" densities save considerable materials and
resources when compared with single family dwellings. The single family houses consume 4
times as much land for streets and roads and 10 times as much for the houses themselves.
The single family houses use nearly 6 times as much metal and concrete, the mining of
which threatens many of our natural areas. They consume over twice as much gas and nearly
twice as much electricity, and produce over twice as much air pollution with their autos.
And third, let us take a high profile example: New York City. Even with its bright
lights and cold climate, it uses half as much energy per capita as the US average,
reported the New York Times on 15 November l981. Such are the benefits of transit and
walking. All that, and great theatre, concerts, cheap ethnic restaurants, libraries and
stores. Similarly, Europeans and Japanese, with compact urban areas, consume 1/4 to 1/6 as
much gasoline per capita as we do.
But, compared to the gluttonous appetite of suburban sprawl, you can be much less dense
than York City and still conserve substantial amounts of land, material and energy, as San
Francisco densities of Table l show. Savings start occurring with densities which make
transit service viable, frequent and convenient, so that people generally walk, bicycle
and use public transit rather than driving, especially for commuting. A compatible mix of
housing, commercial enterprises and industry helps. Homes are close to jobs, stores,
restaurants, theatres, bars and recreation. The vitality and liveliness of this mix and
density increase a city's attractiveness while cutting its consumption.
Table l. Phillips-Gnaizda
| Resources |
City Apartments |
Village Houses |
Ratio |
| |
|
|
|
| Copper pipe |
2,000 ft. |
10,000 ft. |
5 |
| Arable land |
5,000 sq. ft. |
200,000 sq. ft. |
40 |
| Roadway |
1,000 sq. yds. |
15,000 sq. yds. |
15 |
| Concrete |
17,000 cu. yds. |
9,000 cu. yds. |
1/2 |
| Lumber |
25,000 board ft. |
1,200,000 board ft. |
50 |
| Utility pipe |
450 ft. |
2,500 ft. |
5 |
| Daily postal delivery |
12 ft. |
3,000 ft. |
300 |
| Landscaping water |
500 gals/day |
35,000 gals/day |
70 |
| Heating |
5,000 BTU/day |
27,000 BTU/day |
5 |
| Individual auto |
25,000 miles/month |
90,000 miles/mo. |
4 |
| |
|
|
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Phillips & Gnaizda, "New Age Doctrine is Out to Lunch on Three
Issues,"
CoEvolution Quarterly, Summer 1980
Table 2 The Costs of Sprawl (1974 $)
|
Single family (3 units/acre) |
Moderate density* |
Ratio |
|
|
|
|
| Streets and Roads |
3080 $/unit |
801 $/unit |
4 |
| Utilities (metal and concrete) |
5483 $/unit |
958 $/unit |
6 |
| Water consumption |
400 gal/day |
190 gal/day |
2 |
| Gas |
156 therms/mo. |
66 therms/mo. |
2 |
| Electrical |
10,481 KWh/yr. |
6222 KWh/yr. |
2 |
| Air pollution from autos |
|
|
2 |
|
|
|
|
* E "high Rise Apartments," the highest suburban density studied.
(Central
city 4 - 6 story walkups with no front yard setbacks reach about 100
units/acre). In urban areas streets, roads and utilities will already be in
place, but "infill" might require some enlargement.
"The Costs of Sprawl," Real Estate Research Corporation, l974.
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