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Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

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Old 05-29-14, 09:44 AM   #1
larryfeltonj
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Using Census Explorer to track bike commuting

This may be old hat to some of you, but I've recently become a big fan of the Census bureau's Census Explorer for getting a quick overview of the numbers and per capita percentage of bicycle commuters in a given area before using American Factfinder to get a more complete picture. The good things about Census Explorer is the ease and speed, and the map with figures overlaid. Every time I've applied it to Georgia on a particular topic I've come up with surprises. For instance, when I was looking at foreign born population, in addition to the obvious concentrations (Gwinnett and Dekalb counties), a north Georgia county on the Tennessee line (Whitfield) has one of the heaviest concentrations of foreign born residents in the state.

Applied to cycle commuting, here in Georgia, the counties and census tracts with higher than average bike commuting were very surprising to me, with the exception of Clarke County, where UGA drives the numbers up. Chattahoochee, Appling, and Baldwin counties all had higher than average per capita bike commuting. An even bigger surprise to me was that, at the census tract level, Clayton County wins the prize, with a census tract where bike commuting gets over 10% of the commute share. I haven't dug into the numbers yet, but I suspect the absence of MARTA in a county with a large number of low income people pushes that number up.

I've decribed the simple steps for quickly pulling up a map in a post at Atlanta Larry.
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Old 05-29-14, 09:54 AM   #2
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This is funny. My neighborhood in Austin has "0" bicycle commuters. About what I've seen in riding around, too. My whole zip code has 17. I saw two yesterday, which was far more than normal. The good thing is that we have some nice bike lanes with no parked cars, and normally they are all mine.
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Old 05-29-14, 10:10 AM   #3
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They don't appear to know about me either. Somehow I feel a little slighted ...
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Old 05-29-14, 10:11 AM   #4
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Originally Posted by andyprough View Post
This is funny. My neighborhood in Austin has "0" bicycle commuters. About what I've seen in riding around, too. My whole zip code has 17. I saw two yesterday, which was far more than normal. The good thing is that we have some nice bike lanes with no parked cars, and normally they are all mine.
One thing to bear in mind is that the numbers reflect only bike commuters. I haven't dug deeper into how the Census is wording the questions on their commuting survey (I'm going to do that over the weekend) but my assumption is that the number is limited to using a bike to commute to work, and maybe school. Utility cyclists and recreational cyclists would be excluded from the numbers. There's an enormous amount of cycling visible in the area of Cobb County near the Silver Comet Trail, because of the proximity to the trail itself. But the commuting numbers are still low.
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Old 05-29-14, 10:17 AM   #5
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They don't appear to know about me either. Somehow I feel a little slighted ...
It's one of the problems of surveys in general. The best you can get from polling data is a general idea of the percentages in the area, unless you are one of the people American Community Survey contacts. I feel certain though, that areas showing a high number have more commuting than areas showing a low number, and that the difference in percentage is probably pretty close.
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Old 05-29-14, 10:45 AM   #6
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I've lived in Decatur, GA. for three years and have never seen nor filled out a census. So I'm sure the numbers are underreported by at least "one".
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Old 05-29-14, 11:42 AM   #7
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Originally Posted by larryfeltonj View Post
It's one of the problems of surveys in general. The best you can get from polling data is a general idea of the percentages in the area, unless you are one of the people American Community Survey contacts. I feel certain though, that areas showing a high number have more commuting than areas showing a low number, and that the difference in percentage is probably pretty close.
Except that my census tract shows "0" - all of Alpharetta except for one census track shows 0, and that tract shows "62".

I'm sure that they project the absolute number from the sample set to the total population, so there is going to be some room for error. But still, that seems way off. Maybe I ought to swing out by the "62 cyclists" tract some mornings and see if there really is that much more traffic of bicycle commuting.
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Old 05-29-14, 01:46 PM   #8
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Originally Posted by wphamilton View Post
Except that my census tract shows "0" - all of Alpharetta except for one census track shows 0, and that tract shows "62".

I'm sure that they project the absolute number from the sample set to the total population, so there is going to be some room for error. But still, that seems way off. Maybe I ought to swing out by the "62 cyclists" tract some mornings and see if there really is that much more traffic of bicycle commuting.
That does bring up an interesting question regarding the American Community Survey, which is the way they keep census figures current. The decennial census, the one done every 10 years tries to survey everyone. Until the 2000 census there was a long census (more questions, sent to fewer people) and a short census (sent to most households). Since then sampling surveys are done every year. My question would be: does each census tract get included in the ACS, or are tracts sampled, too? I'll see if I can find that out and post it here. If tracts are sampled it could explain your area, particularly if cycle commuting jumped between 2010 and now. The data could have picked up commuters in one tract in the ACS, but still be using decennial and older ACS data for the other tracts.

Last edited by larryfeltonj; 05-29-14 at 01:47 PM. Reason: correcting a typo
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Old 05-29-14, 03:07 PM   #9
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Wow, there are 11 in my census tract! but the one next to it is 5 which i dont think is right, and on the other side is zero which i know isnt right... Hmmm...

- Andy
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Old 05-29-14, 05:21 PM   #10
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Aww, my tract has 75, and there are quite a few pockets in my area that are up to 13% Not too surprising though, I see a lot of other commuters on my way to and from work

Very cool map, thanks for sharing
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Old 05-29-14, 05:23 PM   #11
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Originally Posted by larryfeltonj View Post
One thing to bear in mind is that the numbers reflect only bike commuters.
Bike commutes by all students are excluded.
All utilitarian non-commute trips are excluded.
Only commuters who ride a bike to work for more than 50% of their commutes are counted.
Individuals who have mixed commutes involving cycling would only be counted if more than 50% of their commute distance is by bike.
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Old 05-29-14, 07:21 PM   #12
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Originally Posted by spare_wheel View Post
Bike commutes by all students are excluded.
All utilitarian non-commute trips are excluded.
Only commuters who ride a bike to work for more than 50% of their commutes are counted.
Individuals who have mixed commutes involving cycling would only be counted if more than 50% of their commute distance is by bike.
All of the other commuters I see on the Greenway are fair-weather, probably less than 50% of the time and I've never seen one on the three streets that I travel, so I may well be the only one in Alpharetta beyond the one tract. But it still feels like being slighted, the big goose-egg here.
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