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Introduction to DIY bike ridership research

A lot of people ask me how many people are out there bicycling.

“Not a lot”, I tell them.

And I explain why: the primary source of data is the American Community Survey, which is a questionnaire that asks people questions about how they got to work in a specific week. (More details on how it does this below.) We don’t have data, except in rare “Household Travel Surveys”, about trips by bike to school, shopping, and social activities.

It’s comparable across the country – you can get this data for any city.

Here’s how:

  1. Visit the “legacy” American FactFinder and select American Community Survey, operated by the United States Census Bureau.
  2. Select 2005-2009 American Community Survey 5-Year Estimates (or the latest 5-year estimate). This is the most accurate data.
  3. In the right-side menu that appears, click on “Enter a table number”.
  4. In the new window, input the table number ” S0801″ (“Commuting Characteristics by Sex”) and submit the form. The new window will close and the other window will go to that table.
  5. Now it’s time to select your geography. In the left-side menu, under “Change…” click on “geography (state, county, place…)”
  6. In the window to change your geography, select “Place” as your “Geographic Type”.
  7. Then select the state.
  8. Then select your city and click “Show Result”.
Notes:
  • This data shows all modes people take to work, who live in that city. It’s highly probable that people are leaving the city to their jobs on these modes. For example, someone who lives in Rogers Park may ride their bike to work in Evanston.
  • The URL is a permanent link to this dataset. Each city has a unique URL. You should save these as bookmarks so you can easily reference the data later.
  • The question on the survey doesn’t allow multiple choices: “People who used more than one means of transportation to get to work each day were asked to report the one used for the longest distance during the work trip”.

Some disjointed thoughts about bike commuting rates and how we get them

  1. In November 2010, I wrote that Minneapolis and St. Paul, Minnesota, have a higher percentage of workers (16 and older) commuting to work by bicycle.
  2. Yesterday, I updated an article about how the frequency of women in Chicago bicycling to work is decreasing.
  3. Today, I started updating the November Minnesota article to include the 2007-2009 3-year estimates from the American Community Survey (which shows that bicycling to work is growing faster in Minneapolis than Chicago). View the rudimentary spreadsheet. Bottom line: MPLS jumped from 3.55% bike mode share to 4.14% and Chicago only went from 1.04% to 1.13% (but again, only counting employed people!). Can we get some recession job statistics?
  4. Unemployment rate in Minneapolis-St. Paul-Bloomington, MN-WI MSA is 6.5%; Chicago-Joliet-Naperville, IL-IN-WI MSA is 9.0%. See the table on Bureau of Labor Statistics.

But now I must pause and look at what I’m analyzing.

Someone pointed out in the comments on Chicago bicycling (and working) women that the sample size is low and the margin of error high meaning it’s hard to make accurate interpretations of the change in ridership from year to year. He suggested increasing the sample size.

Add this to the fact that the Census Bureau only collects data on trips to WORK and not everywhere else that people go daily. In this recession, fewer people are working. In fact, perhaps women lost their jobs more frequently than men. That could perhaps explain the drop in women bicycling to work. To increase the number of women bicycling to work, perhaps we just need to find more jobs for women. See points 3 and 4 above for evidence on the number of people who bicycle for transportation that we’re not counting.

After thinking these things over, my point is that gauging a city’s ridership based on Census Bureau home to work data is insufficient.

If these Phoenix bike riders aren’t going to work, they aren’t being counted.

To move from a bicycle subculture to a bicycle culture, we’ll need to know when we get there. We need a better picture on who is riding and for what purpose. CMAP rarely performs their household transportation survey (which gathers data on all trips on all modes and in many counties) and when they do, they don’t single out cities. In essence, Chicago doesn’t know where or why people are riding their bicycles (except for the limited and noisy information the Census or American Community Survey provides) – we have no good data!

Both New York City, New York, and Portland, Oregon, methodically perform bicycle counts annually. Both cities also count ridership on their bridges: Portland has at least 5 to count, NYC has over 10 (also called a screenline count). They can report how many people are riding bikes on the street, blind to their trip purpose and destination. It’s easy to note changes in ridership when you count all trips over work trips.

What I do for a living

Everyone asks, and I always tell. But I’ve never blogged about it.

I’m the Bicycle Parking Program Assistant at the Chicago Bicycle Program, in the Chicago Department of Transportation’s (CDOT) Division of Project Development.

According to the Chicago Municipal Code, I tag abandoned bikes. After 7 days, a CDOT crew removes them to Working Bikes Cooperative.

I arrange for…

  • The installation of bike racks, including at Chicago Transit Authority train stations
  • The maintenance and removal of bike racks
  • The removal of abandoned bikes

I also manage the Chicago Bicycle Program website, Facebook Page, Flickr accountgroup, and Twitter.

What the Census says about bicycle commuting

UPDATE 11-08-10: I wrote a post comparing the commuting statistics between Chicago, Minneapolis, and St. Paul.

UPDATE 02-12-11: Added 2009 data.

Prompted by this entry on BikePortland about the rise of bicycle commuting and the bicycle mode share in Portland, Oregon, I decided to research what the American Community Survey says about the mode share of bicycles as part of commuting where I live: Chicago. I’ll also post bicycle’s share of commuting for other locales, as well.

Some definitions, first:

  • Commuting means travel to and from work – the Census Bureau calls this “MEANS OF TRANSPORTATION TO WORK.” The Census Bureau does not collect information on travel to shopping, medical services, and other places in the decennial census or the yearly American Community Survey (which will supposedly replace the decennial census).
  • Block means the smallest area for which the Census Bureau reports statistics. Any smaller and the possibility that someone could personally identify you from the responses increases. Find your block. The American Community Survey reports information for much larger areas: In some cases, researchers can only select data at the county level. The Census Bureau provides information for the City of Chicago and other municipal divisions of many counties in Illinois.
  • Subject definitions. These describe the question asked to participants and include clarifying information in the case the participant doesn’t understand the question, or their answer is complex. Download the subject definitions for the 2008 American Community Survey.
  • Margin of error (MOE) means the high and low end of confidence. Read more about margin of error on the Census Bureau’s website.

For the American Community Survey, I found table S0801, Commuting Characteristics by Sex. In the decennial census, I found table  P30. MEANS OF TRANSPORTATION TO WORK FOR WORKERS 16 YEARS AND OVER. If you want to check my research, look for these tables of sample data.

Chicago:
Margin of error for male and female categories varied. Combined always reported 0.2%.

  • 2009 – 1.1% travel to work by bicycle. 1.8% male (MOE: 0.3%), 0.4% female (MOE: 0.1%). Workers over 16: 1,271,744. Permalink.
  • 2008 – 1.0% travel to work by bicycle. 1.5% male (MOE: 0.3%), 0.5% female (MOE: 0.2%). Workers over 16: 1,260,741. Permalink.
  • 2007 – 1.1% travel to work by bicycle. 1.4% male (MOE: 0.3%), 0.7% female (MOE: 0.2%). Workers over 16: 1,230,933. Permalink.
  • 2006 – 0.9% travel to work by bicycle. 1.2% male (MOE: 0.3%), 0.7% female (MOE: 0.2%). Workers over 16: 1,209,122. Permalink.
  • 2005 – 0.7% travel to work by bicycle. 0.9% male (MOE: 0.1%), 0.4% female (MOE: 0.1%). Workers over 16: 1,162,550. Permalink.

United States:
Margin of error happened to be the same for each reported category (combined, male, female).

  • 2009 – 0.6% travel to work by bicycle. 0.8% male, 0.3% female. MOE: 0.1%. Workers over 16: 138,591,804 (decrease). Permalink.
  • 2008 – 0.5% travel to work by bicycle. 0.8% male, 0.3% female. MOE: 0.1%. Workers over 16: 143,995,967. Permalink.
  • 2007 – 0.5% travel to work by bicycle. 0.7% male, 0.2% female. MOE: 0.1%. Workers over 16: 139,259,684. Permalink.
  • 2006 – 0.5% travel to work by bicycle. 0.6% male, 0.2% female. MOE: 0.1%. Workers over 16: 138,265,905. Permalink.
  • 2005 – 0.4% travel to work by bicycle. 0.6% male, 0.2% female. MOE: 0.1%. Workers over 16: 133,091,043. Permalink.

Read the BikePortland article if you want to know that Portland has a higher share of commuters traveling by bicycle than Chicago has.

And what about my block? As I mentioned above, we can only find information at the block group level in the decennial census. I live in Block Group 1 of Census Tract 6009 in Chicago, Illinois. I didn’t live here in 2000, though, the last time the decennial census occurred. Back then, out of 168 workers over 16, 4 of them rode their bikes to work! That equals .024% of the worker population in my block group. Oddly, though, the Census Bureau reported 946 people living in this Block Group. Looking at table P8 (Sex By Age), I see that 674 have at least 16 years of age. 178 people have at least 55 years. Does this mean a lot of people in the Block Group didn’t work at the time of the survey in 2000? I don’t know. Permalink to data.

By far, though, driving alone won as the most popular way to get to work: 71.423% of the worker population.

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