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So I’ve recently become interested in why Americans don’t walk and bike more, and tried to figure out what “more” meant anyway.  I didn’t want to mistake my own suburban existence for the entire nation.  There’s plenty of that  from pundits living far more urban and exurban existence than mine.  So I decided to look at the whole country.

Transportation behavior is poorly and unevenly documented.    We do the best job at documenting what happens in traffic and in transit, but almost nothing is recorded for walking and biking.  That’s understandable, as the first two cost a lot to build and operate, and when vehicles bump against each other or leave their lanes, it is a big expensive problem for somebody.  Biking and walking are rarely so high  stakes.  What’s worse is we only record specific geographic information for transportation nationwide for the journey to work.  That seems important until you realize that commuting only accounts for 20% of the miles we travel.  The reason it is such a pain is we do it on 10% of the clock.  Again, maybe the pain is why we record it.

There’s another problem with this data.  People can reach different conclusions based on which scale they look at.  You can reach entirely different conclusions about the policy implications of anything like poverty, crime, guns, or transportation by choosing whether to look at the national, state, county, city or local scale.  For example, many have said that Los Angeles is a far more walkable urban city than Portland, based on the average density of the metropolis.  There are many specific places in Portland I would call walkable, but only a few in Los Angeles, however.

So I decided to look as locally as I could, for the whole country, at census Block Groups.

The problem is, I don’t know what the best way to present this data.  Note that the tiny specks are individual block groups where a transportation mode other than traffic is used at least 10%.  The blank part of the map is most likely using traffic or work  for the vast majority of its trips.

National Maps?


^ Block groups with >10% transit commute share

Regional Maps?

^^ Block Groups with >50% Walk Share

or column graphs, which show the aggregate numbers, but not where they are?

What do you think?

By the way, the most interesting realizations from this is how rare biking is and how rural walking is.  Check these two regional maps out, and a graph of household size by mode.


^^ Block groups with >10% Bike share


^^ Block groups with > 10% Walk share.

Note the size of the block groups, indicating large, spread out populations.  Now look at this:


Household sizes for every other mode are near the 2.59 person mark, but for areas where walking is the predominant (>50%) commute mode, household sizes are over double the average.  I suspect rural work, poverty, or both.  That is not the sort of data I gathered however, but if you are interested I’ll tell you exactly how to get it.

Friday I’m going to talk about a difficulty with wind power.  Monday is going to be a Christmas special.