|
About this calculatorThis analysis was assembled by people who love cities and recognize their benefits to their inhabitants and to the environment. We have also gotten together with our neighbors to plan for our community’s growth. We glory in cities. They house human culture. In the Calculator, we have used the best data we have to quantify some of these benefits. However, there are barriers to democratic planning for growth that spreads the benefits fairly, and benefits the whole community. Since WWII, our government and banking structure have worked to destroy central cities and limit citizens’ choices:
Despite these challenges, cities still house our nation’s culture: museums, libraries, orchestras, rock and rap bands, restaurants, ethnic neighborhoods, shopping and parks. At densities high enough to provide many nearby destinations, so you can walk or take public transit. You meet neighbors and visitors, and enjoy their neighborhoods, cultures, traditions and festivals. Our best cities are improving public transit, calming traffic to enhance walking and bicycling, and removing freeways. Perhaps most important in a world drawing smaller yet still divided by misunderstanding and hate, cities allow you to know other cultures. It is harder to hate those who have different histories and traditions when you have walked their neighborhoods, tasted their culture and found similar hopes and fears. Get out – taste and enjoy of the richness and wonders of cities. We dedicate this webpage to the great cities of the world. Up to Top Why This Title -- Healthy Growth Calculator?
Up to Top What is smart growth?Smart Growth incorporates a planning process: neighbors coming together with architects and planners to plan their community’s future. This process reaps the residents’ ideas, wisdom and knowledge of the community and its history, and their commitment to the community. Smart Growth on the community level includes the interest and excitement brought by a variety of neighborhoods, and their diversity of density, building heights, ethnicity and income. Smart Growth includes a vibrant pedestrian environment, rich in markets and restaurants, interwoven with residences. These attract many to walk, bicycle and take public transit, and allow the diverse groups to enjoy each other. Smart Growth includes solid and attractive architecture, built to green building standards. Smart Growth includes parks, streams and wildlife corridors. Natural areas and farmlands are protected from urban encroachment. Smart Growth includes clean, safe, convenient and affordable public transit. Smart Growth includes strong schools, libraries, museums, health care and other vital community services. Up to Top
Help us improve our analysis.Logic suggests that it takes less concrete, lumber, pipes, wiring and other materials as densities increase due to shared walls, foundations and roofs, and less roadway. But material use might intensify at densities above 100 units per residential acre, which require mid- or high-rise construction, and additional seismic strengthening in some areas. We don’t have this relationship quantified, but we would like to. Similarly, heating and cooling energy should be lower at higher densities as walls, ceiling/floors and roofs are shared and average units decrease in size. But we don’t have the data to justify putting numbers on these impacts. We would like to include these and other comparisons where levels of consumption differ substantially by density. Please contact John Holtzclaw if you have data to support such comparisons, or better data than we have used in our equations. Up to Top
Which measure of density Is used?Brookings’s “Who Sprawls Most? How Growth Patterns Differ Across the U.S.” 2001, uses population per total acre for metropolitan areas – gross population density. The Brookings measure differs from the Healthy Growth Calculator’s density in that Brookings includes streets, commercial, industrial, parks, farms, etc. along with residential – total area. And of course it is the urbanized area average, not the individual neighborhoods which often vary in density by a 100 or more within the same urbanized area.
Brookings’ highest density city, Honolulu, is not your image of urban jungle, but rather a tropical paradise jungle! Yet it is 50% denser than number 2, LA. Why is this romantic city the densest? Development and parks have filled the flat areas, which are bordered by steep mountains and the ocean on three sides, and military bases to the west. The nearest substantial undeveloped flat land is a long winding drive or boat ride away. The oversized McMansions which scar much of the countryside elsewhere are not in vogue here; most housing consists of small apartment buildings or single family housing with modest yards. Consequently, people gather in public parks and other public places, generating a sense of community. The density also leads to higher bus use. Honolulu probably averages 5 to 10 households/residential acre, depending on the fraction of land nonresidential and the family size. So it averages above the sprawl range (1 to 5 hh/res ac). New York, whose density many like to slam, is surrounded by so many very low density suburbs, such as forests with one house per 2 acres, that it comes in as third densest. But does anyone argue that Honolulu’s neighborhoods are denser than Manhattan’s? Honolulu’s densest (hh/res ac) census tract, mid-rise apartments off the highway against the mountains, are far below Manhattan’s 800 hh/res ac or so. LA’s sprawl is constrained enough by desert and mountains to bring it in as number 2 – above New York’s metropolitan area average. Up to Top
What can we learn from the Brookings study?
So the message when planning for growth is:
Brookings also found that higher density urban areas (less sprawl) saves wetlands and prime agriculture. Up to Top
What density should a city be?None, in fact the question doesn't make sense. An exciting, vibrant city has a wide range of densities, as San Francisco does. That affords renters and buyers choices of housing, convenience, neighborhoods and transit accessibility. These neighborhoods range from single family to highrise, with some offering nearby working and shopping choices – maybe even next door or downstairs. Parks, rivers and other open spaces are woven into this residential fabric. Commercial, office and clean industry are nearby. However, since WW II most of our urban areas have sprawled outward, consuming vast farmland and natural areas, even in regions losing total population. This reduces open space available and within reach of all members of the community, especially the low income and those without ready access to autos. The sprawling development has separated housing from markets, restaurants and jobs, lengthening trips, increasing traffic congestion, making public transit service expensive, and discouraging and endangering walking. This type of development requires more construction materials, heating and cooling energy and water use. Residents of sprawl have little nearby shopping, services, jobs or public transit, and so must drive much farther, creating congestion, polluting the air and water, and incurring much higher transportation costs. That results from sprawl zoning, which mandates single-density housing served by networks of wide roads, and prohibits markets, restaurants or most jobs in residential areas. Planning for future growth should have the participation of the whole community; no more backroom deals. All the options should be on the table and the big picture considered. Growth should benefit the whole community, and be fair to everyone. Efficient development saves land, as this calculator indicates. Compact smart growth uses up less farmland and generates less water and air pollution, and traffic, especially when clustered around transit centers. It benefits the whole community be reducing trip lengths, congestion and pollution, and by preserving natural areas. While many things affect neighborhood livability and efficiency, residential density provides an excellent measure of this consumption. Up to Top
But isn't dense housing expensive?It often is; San Francisco's densest, most convenient, neighborhoods are so popular that renters and buyers bid up the prices well above housing in low density areas. They call it the free market. Ironically, apologists for sprawl often claim that no one wants to live in dense areas, even while they are arguing that families are moving out to sprawl to get affordable housing. Hello? However, the cheapest housing to build, per square foot or per unit, is 3 to 4 stories -- sticks on concrete foundations. Above that, at least in California, seismic considerations require more reinforced concrete or steel, raising the costs. Similarly, land per unit is cheaper at high densities even though the land costs more. For instance, 100 units on a $500,000 acre is $5000 per unit; whereas 3 units on a $100,000 acre in sprawl is $33,000 per unit. So why are the prices for new city center condos so expensive? Profits! Doesn't the market tell us that a solution to exaggerated prices is to construct much more Smart Growth housing in central neighborhoods, especially in warehouses and on other underused land, and to create Smart Growth areas around transit centers outside central cities. Use competition to bring down rents and prices. Up to Top
What about gentrification?Gentrification threatens many present central area residents, especially renters. But it also brings benefits to residents, including better schools and parks, more choice of markets, restaurants and jobs, better policing, cleaner and safer streets, better public transit, and income and ethnic diversity. Existing residents can be protected from excessive rents or evictions:
Planning for and constructing additional “affordable housing” in popular dense areas can relieve pressure on rents and real estate prices. Inclusive zoning ordinances can make newly constructed housing affordable to low-moderate income teachers, nurses and store clerks. Up to Top
Don't we have enough high-density housing?High housing prices in convenient, dense areas show that we could use much more. But hey, don't we need more single family housing for families? In the San Francisco Bay Area, for instance, 24% of households are adults with children, those for whom single family housing is presumably necessary. However, 54% of Bay Area housing units are single family detached, so we have over twice as many as are “needed”. And nevermind that the 16% of San Francisco households that are adults with children do quite well in dense areas, thank you. Our demographics are changing: our population is aging. Do most empty nesters need 4 bedrooms, or to be stuck in an area where they have to drive every time they want a loaf of bread? Four old guys were talking, and one said: "You know, it's getting so bad I can't recognize faces 10 feet away, can't turn my head quickly, can't understand my wife, or bend over. The only thing I have to be greatful for is my drivers license." We should be planning convenient neighborhoods, with good public transit, to allow these folk to age gracefully and safely. Our tax laws should facilitate selling a big house and moving to a convenient community. Please contact John Holtzclaw if you have data to support such comparisons, or better data than we have used in our equations. |
Let’s look at how neighborhood density varies in the city of San Francisco.
The densest zone is 536 households/residential acre (2000 census),
mostly 3 to 16 story apartment and commercial buildings, with a few to 30 stories.
(Typical of high density zones, only 15% of the zone’s acreage is residential.
The zone abounds in restaurants, including very affordable ethnic restaurants,
7 live theatres, shopping and grand hotels. That is why it is so convenient
and trips are so short.) Census tracts in The City range down to 5 households
per residential acre, and average 19. This marvelous variety makes The City
more interesting and offers residents choice of a great variety of neighborhoods,
shopping, transit, schools and travel mode. Sprawl outside San Francisco, in
the metropolitan area, ranges down to 0.4 households/residential acre. Convenience,
trip lengths, travel patterns and congestion vary greatly between 0.4 and 536
households/residential acre.