Updated cumulative population by density, 2010 census

Among our excuses for not riding bicycles is that America is too spread out. This explains why we don’t ride cross country very often, but not why we don’t ride to the grocery store. In fact, a whole lot of us live in places that are quite dense. I attempted to graph this before using 2000 Census data and “50K areas” but I was unhappy with the result, both because of my errors and because 50K area leaves out a lot (I live in a town of 25000, for example).

Happily, with new data, organized by non-overlapping zipcode, I can solve both those problems. One sixth of us (52 million people) live in places denser than 5362 per square mile; the next sixth, denser than 2786 per square mile, the next sixth, denser than 1292 per square mile (that’s the median density for our population; half of us live in zipcodes less dense than that, too). With all the zipcodes included it’s clear that many of us live in plenty-dense places.

I’ve tagged the graph with densities of towns and cities near Boston, mostly inside 128, plus all of Boston, and also plus three European cities known for their relatively high bike trip share. I added some other US cities for comparison.

This graph is cumulative, meaning that the Y axis is the sum of all the people living in zipcodes with a density of X or more. For example, about 30 million people live in places with 8000 or more people per square mile.

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