Tag: American Community Survey

How many cars are in Rogers Park?

November 10, 2013 / / 4 Comments

There are a gazillion cars in Rogers Park, and there’s no place to park them. That’s the declaration you would gather if you listen to “Lakefront Car Tower” (a parking garage) proponents, including the 49th ward alderman, Joe Moore.

The parking problem is so bad in Rogers Park that a parking garage at Sherwin Avenue and Sheridan Road that would provide less than 100 overnight parking spaces to the public was actually sent from Asphaltia, the god of car parks. It’s so bad that “[m]any car owners find themselves stuck in their home at night” – yes, the alderman really published that on his website – because they find a parking space on Friday night and can’t move the car until Monday morning. The horror of using your feet, pedals, the bus, the train, car sharing, paratransit, or a Segway!

(I’d love to get into parking pricing policy now, but I’ll just leave you with this: of course there is going to be a demand problem when the supply of publicly-owned on-street parking costs $0 per year.)

This post is actually a tutorial on how to use United States Census data to find how many cars are in the neighborhood of Rogers Park, not a laugh about Asphaltia’s teachings.

Let’s begin! Continue reading

Finding a new way to measure cities’ bike friendliness in the United States

November 3, 2012 / / 8 Comments

A really smart person could come up with a way to measure day-to-day bike friendliness based on how well cities adhere to standards that keep roads clear of obstructions that further frustrate the commute, like construction projects that squeeze bikes and cars together. 

I work at home. There are some days when I only leave my house to get milk from the Mexican grocery store at the end of my block (which makes awesome burritos). That means I ride my bike half as much as people who commute to work. on their bikes. Today I had a bunch of errands to run: drop off stuff, buy stuff, take pictures of stuff for my blog, Grid Chicago.

It was a very frustrating experience. I don’t need to go into details about how I was harassed by people who the state so graciously awarded a license to drive. But it happened. And it happens a hundred times a day to people cycle commuting in Chicago. I got to thinking about “bike friendly” cities. Is there a way to incorporate driver attitudes in there? I tweeted:

[tweet_embed id=264575958374305792]

Later I had the idea to use some very simple but objective measurements to create a new bike friendliness metric. It would help ensure that “Silver” (a ranking the League of American Bicyclists [LAB] uses) in one city means the same as “Silver”. It can expand from here but basically it works like this:

  • The share of people going to work who go by bike is a proxy for how “friendly” a city is to biking.
  • If a city has a lot of people biking to work, it must be friendly.
  • If a city has a few people biking to work, it must be non-friendly.
  • Cities are compared to each other to determine friendly and non-friendly.
  • The metric uses standard deviation to score cities.

Stop me if this has already been done.

I created a spreadsheet that lists the top 10 populous cities in the United States. I then added 10 more cities: Austin, Boston, Davis, Madison, Minneapolis, Portland, San Francisco, Seattle, and Washington, D.C. In the next column I listed their bike commute share from the American Community Survey 2006-2010 5-year estimates. I calculated the standard deviation and mean of these shares and then in another column used Apple Numbers’s STANDARDIZE function:

The STANDARDIZE function returns a normalized value from a distribution characterized by a given mean and standard deviation.

I think that’s what I want. And the output is close to what I expected. I then found the LAB ranking for each city and found the variance of each ranking to see how far apart each city within one ranking was from another city in the same ranking. The results were interesting: the higher the ranking, the more variance there was.

Hurricane Sandy prompted a lot of New Yorkers to bike. It made headlines, even. Photo by Doug Gordon. 

I wanted to add another metric of bike friendliness, and that’s density. To me, a higher density of people would mean a higher density of places to go (shop, eat, learn, enjoy) and friends and family would be closer, too. Or the possibility of meeting new people nearby would be higher. Yeah, I’m making a lot of assumptions here. So I applied the STANDARDIZE function there as well. I added this number to the previous STANDARDIZE result and that became the city’s score.

So, in this new, weird ranking system, the most bicycle friendly cities are…drum roll please…

  1. Davis, California (Platinum)
  2. New York City (Silver) *
  3. San Francisco (Gold) *
  4. Boulder (Platinum)
  5. Boston (Silver)
  6. Philadelphia (Silver)
  7. Tie: Chicago*, Washington, D.C. (Silver)
  8. Tie: Portland* (Platinum), Minneapolis* (Gold)

Remember, I said above that any author of a list should spend at least a day cycling in each city. I’ve starred the cities where I’ve done that – I’ve cycled in 5 cities for at least a day.

I only calculated 20 cities. Ideally I’d calculate it for the top 50 most populous cities AND for every city that’s been ranked by LAB.

LAB cities list (PDF). My spreadsheet (XLS).

Stats from the OECD: Comparing traffic injuries of the United States and Netherlands

May 21, 2012 / / 0 Comments

For an article I’m writing for Architect’s Newspaper about the Chicago Forward CDOT Action Agenda, I wanted to know about traffic injuries and fatalities in the United States, but compared to the Netherlands and Denmark and other places with a Vision Zero campaign (to have 0 traffic deaths each year).

I already knew the OECD had a good statistics database and web application. With a few clicks, I can quickly get a table of traffic injuries (casualties) listing just the countries I want. I can easily select the years I want, too.

In one more click the web application will show a time animated bar chart. A feature I’d like to see added is dividing the figure (in this case traffic injuries) by the population. Check out the video to see what it looks like. The United States looks to be in terrible shape, but our country has several times more residents.

I had trouble downloading and opening the CSV file of the data table I created. The XLS file was damaged, also. The built-in Mac OS X Archive Utility app couldn’t open the .gz file, but I used The Unarchiver app successfully.

My calculations, based on data from OECD (national population and traffic fatalities), Illinois Department of Transportation (IDOT), and the American Community Survey:

Fatalities per 100,000 in 2009

  • United States: 11.02472
  • Denmark: 5.48969
  • Netherlands: 4.35561
  • Sweden: 3.84988
  • Chicago: 16.74891
  • United Kingdom: 3.83555

Chicago’s fatality rate per 100,000 citizens in 2009 was 16.75 (473 deaths on the roads). The fatality rate dropped in 2010: just 11.65 deaths per 100,000 residents (315 deaths on the roads; the population also decreased).

Updated September 28, 2012, to add the United Kingdom. 

Introduction to DIY bike ridership research

September 20, 2011 / / 0 Comments

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”.

Commuting rates in Chicago – a conversation

April 5, 2011 / / 0 Comments

I had this conversation last night with a friend from Chicago. Enjoy. Data is from the American Community Survey, Table S0801. If you were to rate how much we bike, from a “typical Chicagoan’s” point of view, he would be “eccentric” and I would be “psychotic.”

Photo by Joshua Koonce.

Me
A friend of mine in Europe asked for bicycle commuting statistics for Chicago.
Man, the numbers were sad.

Friend
No shit.

Me
if we look at the 3-year estimates for work trips, then it’s
-2005-2007: 0.9%
-2006-2008: 1.0
-2007-2009: 1.1

Friend
Chicago is also a gigantic, sprawling modern city of hundreds of square miles and wide roads designed for masses of cars.

Me
And if we look at the 1-year estimates, which Matt argued on my blog are useless, it’s
-2005: 0.7%
-2006: 0.9
-2007: 1.1
-2008: 1.0
-2009: 1.1
The 3-year estimate has a MOE of ±0.1 so essentially, it could mean no change from year to year.
And the 1-year estimate has a MOE of ±0.2, so again, it could mean no change from year to year
UGH

Friend
Comparatively, old European cities don’t have a lot of bandwidth for autos and have density where people take short trips.
That’s still probably two or three times the distance people in Copenhagen or Cambridge or Amsterdam.

Me
So let’s say 50% of trips are 5 miles or less, and 25% of trips are 2.5 miles or less.
Yet 1% of all trips are taken by bike
If we could just DOUBLE that, it would be a miracle
The Bike 2015 Plan’s goal is to have 5% of all trips under 5 miles by bike.

Friend
That’s an ambitious goal.

Me
We don’t have any baseline data to show how many trips under 5 miles in 2006, at the inception of the Bike 2015 Plan, are by bike. In the end, we’ll never know if our ambitious goal was attained!