Density 

In 2000, Ann Arbor's density was similar to that of Warren or Dearborn.  Berkeley, CA, Grand Rapids, and Royal Oak, MI had higher densities. Source: 2000 U.S. Census

Population Densities of American Cities (over 50,000)

*            Density in Ann Arbor declined .2% since 1990. 

Source: 2000 U.S. Census:  Population per Square Mile
(This is only a sample of the jurisdictions included in the census.)

What is population density?

Population density is a measurement of total citizens per square mile.

How does population density affect our environment?

The population density indicator serves as a proxy to measure pressures on natural resources, such as water, air and land.

The more people that live in the the region, the more resources are needed to support their presence. However, total population and population growth do not offer an exclusive view of human demographic impact. Population density and distribution are also important. If growth occurs in areas that already contain supporting infrastructure-- for example in the downtown district of Ann Arbor -- this growth is not likely to cause as much environmental impact as growth that occurs along undeveloped stream corridors in less dense areas of town. In already urbanized areas, increased density can positively impact on the environment, as increased development in already urbanized areas can prevent development in more rural areas, reducing overall sprawl. Where housing is integrated into areas with jobs and shopping, transportation impacts may be reduced. 

Top 10 reasons why higher density is a community value:

1. Mass transit is a community value and density supports mass transit. Studies have shown that transit systems work most efficiently in areas that have densities high enough to support it. The City of Ann Arbor is one of the few communities in Washtenaw County that can accommodate higher residential densities along transit corridors.

2. Diversity of housing is a community value and density increases the variety of housing choices. Ann Arbor is one of the few communities in Washtenaw County that can accommodate higher densities and the increased diversity of housing choices that density can bring.

3. Affordable housing is a community value and density provides more opportunities for affordable housing than low density single-family uses.

4. The efficient provision of infrastructure is a community value. It is more efficient to provide infrastructure to compact development projects that scattered homes on large lots.

5. Thinking globally and acting locally is a community value. Major American environmental organizations such as the Sierra Club and the Environmental Defense Fund recommend that new development be compact in nature and directed toward established communities instead of building new low density homes in open space (sprawl).

5. Reducing imperviousness per dwelling unit is community value and a more accurate measure of sustainability than imperviousness per acre.

6. Reducing environmental footprints is a community value. Residential development projects that accommodate units vertically reduce imperviousness and the amount of land necessary to accommodate residents.

7. Energy efficiency is a community value and attached dwelling units are more energy efficient than comparable single-family homes.

8. Regional Planning is a community value and Washtenaw County recently adopted a master plan that recommends future growth be accommodated in existing cities and villages instead of in green fields.

9. Non-motorized transportation is a community value and best supported through higher density, mixed use land use patterns. Low density development patterns reduce non-motorized opportunities by spreading out destinations.

10. Clean air is a community value and higher density development in Ann Arbor results in a higher percentage of residents taking alternative modes of transportation such as mass transit, walking and bicycling compared to low density land use patterns where residents are much more dependant on the automobile.

More information

• SEMCOG Population Data Estimates
• SEMCOG 2030 Regional Development Forecast
• Ann Arbor DiscoversDowntown
• Speaking Up for Density, Huron River Watershed Council