Thursday, October 18, 2012

Density and transit in metro Milwaukee

Greater Milwaukee has had a long and contentious debate about public transit, with one common argument against investing in rapid transit being that the region doesn't have the population density to support it. A recent study from the U.S. Census Bureau, however, may be cause for reexamining that contention. It finds Milwaukee among the densest metropolitan areas in the U.S., with greater population density than many of the nation’s most populous metros, including Atlanta, Houston, and Seattle.

In 2010, the Milwaukee metropolitan area – comprised of Milwaukee, Ozaukee, Washington, and Waukesha counties – ranked 15th in population density among the 102 metro areas in the U.S. with populations over 500,000, with a density of 5,258 persons per square mile. Milwaukee was second only to Chicago among Midwest metros. Notably, the Milwaukee area’s density declined slightly between 2000 and 2010, by 3.6%. This downtick followed a national trend, however, as 33 of the nation’s 50 largest metro areas saw their densities decline during that period. The complete data set can be found here.

Rather than using the traditional method of determining population density, which involves simply dividing total land area by total population, the Census Bureau study used “weighted density,” which averages the densities of each census tract in a metro area while giving each tract a relative weight based on its share of the metro’s total population. Using this methodology, for example, if 75% of a given metro area’s population lives in low-density suburbs, that metro will have a lower weighted density than another metro area of the same size and with the same population where 75% of residents live in medium- or high-density urban neighborhoods.

A frequently-cited example illustrating why researchers are converting to this new method of determining population density is the fact that under the traditional definition, the Los Angeles metro area has a higher density than the New York metro area, which is counterintuitive to anyone who has visited both places. Using weighted density, the New York metro is more than twice as dense as L.A., because the typical New Yorker lives in a denser neighborhood than the typical Angeleno.

While metro Milwaukee is not as dense as New York or Chicago, it is denser than many metro areas considered to have admirable public transit systems, including Seattle and Portland. Milwaukee also is denser than many others that have made recent investments in rapid transit, such as Minneapolis and Phoenix with their relatively new light rail systems, and Cleveland and Kansas City, where bus rapid transit (BRT) systems recently have been developed. 

Rapid transit may come back into Greater Milwaukee’s infrastructure planning at some point in the future. While many factors impact the success of a rapid transit system, we now have a clearer understanding of our population density and how it compares with other metro areas around the country.

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