Which Density Is Best?
Rather than all the same density or type, the neighborhoods of vibrant cities like San Francisco range from single family to highrise, and offer nearby working and shopping choices – often next door or downstairs. Parks, rivers and other open spaces are woven into this residential fabric. Commercial, office and industrial districts are nearby.
Contrast such vibrant cities with sprawling areas of low density cookie-cutter housing which occupy vast areas of land previously natural or rural. 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.
Efficient development saves land, as this calculator indicates. Compact smart growth uses up less farmland and generates less water and air pollution, and traffic. While many things affect neighborhood livability and efficiency, residential density provides an excellent measure of this consumption.